Random Articles (Page 4)

Have a deep view into what people are curious about.

πŸ”— British Pet Massacre

πŸ”— Military history πŸ”— United Kingdom πŸ”— Military history/World War II πŸ”— Animal rights πŸ”— Animals πŸ”— Military history/European military history πŸ”— Military history/British military history

The British pet massacre was an event in 1939 in the United Kingdom where over 750,000 pets were killed in preparation for food shortages during World War II. It was referred to at the time as the September Holocaust, and later sources describe it as a "holocaust of pets". In London alone, during the first week of the Second World War around 400,000 companion animals, about 26% of all cats and dogs were killed.

No bombs were to fall on the UK mainland until April 1940.

Similar events happened in mainland Europe, for example, the killing of millions of farm animals in Denmark due to the lack of imported fodder for them.

Discussed on

πŸ”— Tsiolkovsky Rocket Equation

πŸ”— Spaceflight πŸ”— Physics πŸ”— Rocketry

The Tsiolkovsky rocket equation, classical rocket equation, or ideal rocket equation is a mathematical equation that describes the motion of vehicles that follow the basic principle of a rocket: a device that can apply acceleration to itself using thrust by expelling part of its mass with high velocity can thereby move due to the conservation of momentum.

Ξ” v = v e ln ⁑ m 0 m f = I sp g 0 ln ⁑ m 0 m f {\displaystyle \Delta v=v_{\text{e}}\ln {\frac {m_{0}}{m_{f}}}=I_{\text{sp}}g_{0}\ln {\frac {m_{0}}{m_{f}}}}

where:

Ξ” v Β  {\displaystyle \Delta v\ } is delta-v – the maximum change of velocity of the vehicle (with no external forces acting).
m 0 {\displaystyle m_{0}} is the initial total mass, including propellant, also known as wet mass.
m f {\displaystyle m_{f}} is the final total mass without propellant, also known as dry mass.
v e = I sp g 0 {\displaystyle v_{\text{e}}=I_{\text{sp}}g_{0}} is the effective exhaust velocity, where:
I sp {\displaystyle I_{\text{sp}}} is the specific impulse in dimension of time.
g 0 {\displaystyle g_{0}} is standard gravity.
ln {\displaystyle \ln } is the natural logarithm function.

Discussed on

πŸ”— Sisu

πŸ”— Michigan πŸ”— Popular Culture πŸ”— Finland

Sisu is a Finnish concept described as stoic determination, tenacity of purpose, grit, bravery, resilience, and hardiness and is held by Finns themselves to express their national character. It is generally considered not to have a literal equivalent in English.

Discussed on

  • "Sisu" | 2022-03-02 | 16 Upvotes 2 Comments

πŸ”— Human Anti-Mouse Antibody

πŸ”— Pharmacology

Human anti-mouse antibody or human anti-murine antibody (HAMA) is an antibody found in humans which reacts to immunoglobins found in mice.

πŸ”— Mummy Brown

πŸ”— Ancient Egypt πŸ”— Color πŸ”— Archaeology πŸ”— Visual arts

Mummy brown, also known as Egyptian brown or Caput Mortuum,:β€Š254β€Š is a rich brown bituminous pigment with good transparency, sitting between burnt umber and raw umber in tint. The pigment was made from the flesh of mummies mixed with white pitch and myrrh. Mummy brown was extremely popular from the mid-eighteenth to the nineteenth centuries. However, fresh supplies of mummies diminished, and artists were less satisfied with the pigment's permanency and finish. By 1915, demand had significantly declined. Suppliers ceased to offer it by the middle of the twentieth century.:β€Š82β€Š

Mummy brown was one of the favourite colours of the Pre-Raphaelites. It was used by many artists, including Eugene Delacroix, William Beechey, Edward Burne-Jones, Lawrence Alma-Tadema, and Martin Drolling.

Discussed on

πŸ”— Greenspun's Tenth Rule

πŸ”— Computing πŸ”— Systems πŸ”— Computing/Software πŸ”— Systems/Systems engineering

Greenspun's tenth rule of programming is an aphorism in computer programming and especially programming language circles that states:

Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp.

Discussed on

πŸ”— LK-99

πŸ”— Korea πŸ”— Physics πŸ”— Chemicals πŸ”— Electrical engineering πŸ”— Materials

LK-99 is a proposed ambient pressure and room-temperature superconductor with a grayβ€’black appearance.:β€Š8β€Š LK-99 has a hexagonal structure slightly modified from leadβ€’apatite and is claimed to function as a superconductor below 400Β K (127Β Β°C; 260Β Β°F).:β€Š1β€Š The material was investigated by a team of Sukbae Lee et al. from the Korea Institute of Science and Technology (KIST).:β€Š1β€Š As of 26Β JulyΒ 2023 the discovery of LK-99 has not been peer reviewed or independently replicated.

The chemical composition of LK-99 is approximately Pb9Cu(PO4)6O such thatβ€”compared to pure lead-apatite (Pb10(PO4)6O):β€Š5β€Šβ€”approximately one quarter of Pb(2) ions are replaced by Cu(II) ions.:β€Š9β€Š This partial replacement of Pb2+ ions (measuring 133 picometre) with Cu2+ ions (measuring 87 picometre) is said to cause a 0.48% reduction in volume, creating internal stress inside the material.:β€Š8β€Š

The internal stress is claimed to cause a heterojunction quantum well between the Pb(1) and oxygen within the phosphate ([PO4]3βˆ’) generating a superconducting quantum well (SQW).:β€Š10β€Š Lee et al claim to show LK-99 exhibits a response to a magnetic field (Meissner effect) when chemical vapor deposition is used to apply LK-99 to a non-magnetic copper sample.:β€Š4β€Š Pure lead-apatite is an insulator, but Lee et al claim copper-doped lead-apatite forming LK-99 is a superconductor, or at higher temperatures, a metal.:β€Š5β€Š

Discussed on

  • "LK-99" | 2023-07-27 | 101 Upvotes 58 Comments

πŸ”— Capability Immaturity Model

πŸ”— Computing πŸ”— Systems πŸ”— Computing/Software πŸ”— Systems/Software engineering

Capability Immaturity Model (CIMM) in software engineering is a parody acronym, a semi-serious effort to provide a contrast to the Capability Maturity Model (CMM). The Capability Maturity Model is a five point scale of capability in an organization, ranging from random processes at level 1 to fully defined, managed and optimized processes at level 5. The ability of an organization to carry out its mission on time and within budget is claimed to improve as the CMM level increases.

The "Capability Im-Maturity Model" asserts that organizations can and do occupy levels below CMM level 1. An original article by Capt. Tom Schorsch USAF as part of a graduate project at the Air Force Institute of Technology provides the definitions for CIMM. He cites Prof. Anthony Finkelstein's ACM paper as an inspiration. The article describes situations that arise in dysfunctional organizations. Such situations are reportedly common in organizations of all kinds undertaking software development, i.e. they are really characterizations of the management of specific projects, since they can occur even in organizations with positive CMM levels.

Kik Piney, citing the original authors, later adapted the model to a somewhat satirical version that attracted a number of followers who felt that it was quite true to their experience.

Discussed on

πŸ”— Cleo, the mathematician that tricked Stack Exchange

πŸ”— Biography πŸ”— Internet culture πŸ”— Mathematics πŸ”— Biography/science and academia

Cleo was the pseudonym of an anonymous mathematician active on the mathematics Stack Exchange from 2013 to 2015, who became known for providing precise answers to complex mathematical integration problems without showing any intermediate steps. Due to the extraordinary accuracy and speed of the provided solutions, mathematicians debated whether Cleo was an individual genius, a collective pseudonym, or even an early artificial intelligence system.

During the poster's active period, Cleo posted 39 answers to advanced mathematical questions, primarily focusing on complex integration problems that had stumped other users. Cleo's answers were characterized by being consistently correct while providing no explanation of methodology, often appearing within hours of the original posts. The account claimed to be limited in interaction due to an unspecified medical condition.

The mystery surrounding Cleo's identity and mathematical abilities generated significant interest in the mathematical community, with users attempting to analyze solution patterns and writing style for clues. Some compared Cleo to historical mathematical figures like Srinivasa Ramanujan, known for providing solutions without conventional proofs. In 2025, Cleo was revealed to be Vladimir Reshetnikov, a software developer originally from Uzbekistan.

Discussed on