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๐ CMS Pipelines
CMS Pipelines implements the pipeline concept under the VM/CMS operating system. The programs in a pipeline operate on a sequential stream of records. A program writes records that are read by the next program in the pipeline. Any program can be combined with any other because reading and writing is done through a device independent interface.
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- "CMS Pipelines" | 2016-04-27 | 43 Upvotes 12 Comments
๐ Hundredth monkey effect
The hundredth monkey effect is a hypothetical phenomenon in which a new behaviour or idea is said to spread rapidly by unexplained means from one group to all related groups once a critical number of members of one group exhibit the new behaviour or acknowledge the new idea.
One of the primary factors in the promulgation of the story is that many authors quote secondary, tertiary or post-tertiary sources which have themselves misrepresented the original observations.
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- "Hundredth monkey effect" | 2012-12-24 | 11 Upvotes 6 Comments
๐ Nelson Rules
Nelson rules are a method in process control of determining if some measured variable is out of control (unpredictable versus consistent). Rules, for detecting "out-of-control" or non-random conditions were first postulated by Walter A. Shewhart in the 1920s. The Nelson rules were first published in the October 1984 issue of the Journal of Quality Technology in an article by Lloyd S Nelson.
The rules are applied to a control chart on which the magnitude of some variable is plotted against time. The rules are based on the mean value and the standard deviation of the samples.
The above eight rules apply to a chart of a variable value.
A second chart, the moving range chart, can also be used but only with rules 1, 2, 3 and 4. Such a chart plots a graph of the maximum value - minimum value of N adjacent points against the time sample of the range.
An example moving range: if N = 3 and values are 1, 3, 5, 3, 3, 2, 4, 5 then the sets of adjacent points are (1,3,5) (3,5,3) (5,3,3) (3,3,2) (3,2,4) (2,4,5) resulting in moving range values of (5-1) (5-3) (5-3) (3-2) (4-2) (5-2) = 4, 2, 2, 1, 2, 3.
Applying these rules indicates when a potential "out of control" situation has arisen. However, there will always be some false alerts and the more rules applied the more will occur. For some processes, it may be beneficial to omit one or more rules. Equally there may be some missing alerts where some specific "out of control" situation is not detected. Empirically, the detection accuracy is good.
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- "Nelson Rules" | 2015-07-31 | 219 Upvotes 40 Comments
๐ Purple Earth Hypothesis
The Purple Earth Hypothesis (PEH) is an astrobiological hypothesis, first proposed by molecular biologist Shiladitya DasSarma in 2007, that the earliest photosynthetic life forms of Early Earth were based on the simpler molecule retinal rather than the more complex porphyrin-based chlorophyll, making the surface biosphere appear purplish rather than its current greenish color. It is estimated to have occurred between 3.5 and 2.4 billion years ago during the Archean eon, prior to the Great Oxygenation Event and Huronian glaciation.
Retinal-containing cell membranes exhibit a single light absorption peak centered in the energy-rich green-yellow region of the visible spectrum, but transmit and reflect red and blue light, resulting in a magenta color. Chlorophyll pigments, in contrast, absorb red and blue light, but little or no green light, which results in the characteristic green reflection of plants, green algae, cyanobacteria and other organisms with chlorophyllic organelles. The simplicity of retinal pigments in comparison to the more complex chlorophyll, their association with isoprenoid lipids in the cell membrane, as well as the discovery of archaeal membrane components in ancient sediments on the Early Earth are consistent with an early appearance of life forms with purple membranes prior to the turquoise of the Canfield ocean and later green photosynthetic organisms.
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- "Purple Earth Hypothesis" | 2025-07-24 | 286 Upvotes 79 Comments
๐ Earth as a nuclear furnace (geothermal heat is mostly from radioactive decay)
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 25โ30ย ยฐC/km (72โ87ย ยฐF/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 7,000ย K and the pressure could reach 360ย 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 3ย billionย 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.
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- "Earth as a nuclear furnace (geothermal heat is mostly from radioactive decay)" | 2011-04-03 | 44 Upvotes 14 Comments
๐ 1% rule
In Internet culture, the 1% rule is a rule of thumb pertaining to participation in an internet community, stating that only 1% of the users of a website add content, while the other 99% of the participants only lurk. Variants include the 1โ9โ90 rule (sometimes 90โ9โ1 principle or the 89:10:1 ratio), which states that in a collaborative website such as a wiki, 90% of the participants of a community only consume content, 9% of the participants change or update content, and 1% of the participants add content.
Similar rules are known in information science, such as the 80/20 rule known as the Pareto principle, that 20 percent of a group will produce 80 percent of the activity, however the activity may be defined.
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- "1% rule" | 2020-03-18 | 465 Upvotes 151 Comments
- "1% rule (Internet culture)" | 2014-01-13 | 105 Upvotes 61 Comments
๐ Mind benders: List of paradoxes
This is a list of paradoxes, grouped thematically. The grouping is approximate, as paradoxes may fit into more than one category. This list collects only scenarios that have been called a paradox by at least one source and have their own article. Although considered paradoxes, some of these are simply based on fallacious reasoning (falsidical), or an unintuitive solution (veridical). Informally, the term paradox is often used to describe a counter-intuitive result.
However, some of these paradoxes qualify to fit into the mainstream perception of a paradox, which is a self-contradictory result gained even while properly applying accepted ways of reasoning. These paradoxes, often called antinomy, point out genuine problems in our understanding of the ideas of truth and description.
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- "Mind benders: List of paradoxes" | 2009-07-07 | 15 Upvotes 1 Comments
๐ NEEMO
NASA Extreme Environment Mission Operations, or NEEMO, is a NASA analog mission that sends groups of astronauts, engineers and scientists to live in Aquarius underwater laboratory, the world's only undersea research station, for up to three weeks at a time in preparation for future space exploration.
Aquarius is an underwater habitat 3.5 miles (5.6ย km) off Key Largo, Florida, in the Florida Keys National Marine Sanctuary. It is deployed on the ocean floor next to deep coral reefs 62 feet (19ย m) below the surface.
NASA has used it since 2001 for a series of space exploration simulation missions, usually lasting 7 to 14 days, with space research mainly conducted by international astronauts. The mission had cost about 500ย million U.S. dollars. The crew members are called aquanauts (as they live underwater at depth pressure for a period equal to or greater than 24 continuous hours without returning to the surface), and they perform EVAs in the underwater environment. A technique known as saturation diving allows the aquanauts to live and work underwater for days or weeks at a time. After twenty four hours underwater at any depth, the human body becomes saturated with dissolved gas. With saturation diving, divers can accurately predict exactly how much time they need to decompress before returning to the surface. This information limits the risk of decompression sickness. By living in the Aquarius habitat and working at the same depth on the ocean floor, NEEMO crews are able to remain underwater for the duration of their mission.
For NASA, the Aquarius habitat and its surroundings provide a convincing analog for space exploration. Much like space, the undersea world is a hostile, alien place for humans to live. NEEMO crew members experience some of the same challenges there that they would on a distant asteroid, planet (i.e. Mars) or Moon. During NEEMO missions, the aquanauts are able to simulate living on a spacecraft and test spacewalk techniques for future space missions. Working in space and underwater environments requires extensive planning and sophisticated equipment. The underwater condition has the additional benefit of allowing NASA to "weight" the aquanauts to simulate different gravity environments.
Until 2012, Aquarius was owned by the National Oceanic and Atmospheric Administration (NOAA) and operated by the National Undersea Research Center (NURC) at the University of North CarolinaโWilmington as a marine biology study base.
Since 2013, Aquarius is owned by Florida International University (FIU). As part of the FIU Marine Education and Research Initiative, the Medina Aquarius Program is dedicated to the study and preservation of marine ecosystems worldwide and is enhancing the scope and impact of FIU on research, educational outreach, technology development, and professional training. At the heart of the program is the Aquarius Reef Base.
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- "NEEMO" | 2022-12-10 | 74 Upvotes 16 Comments
๐ The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light
PSR J1748โ2446ad is the fastest-spinning pulsar known, at 716 Hz, or 716 times per second. This pulsar was discovered by Jason W. T. Hessels of McGill University on November 10, 2004 and confirmed on January 8, 2005.
If the neutron star is assumed to contain less than two times the mass of the Sun, within the typical range of neutron stars, its radius is constrained to be less than 16ย km. At its equator it is spinning at approximately 24% of the speed of light, or over 70,000ย km per second.
The pulsar is located in a globular cluster of stars called Terzan 5, located approximately 18,000 light-years from Earth in the constellation Sagittarius. It is part of a binary system and undergoes regular eclipses with an eclipse magnitude of about 40%. Its orbit is highly circular with a 26-hour period. The other object is at least 0.14 solar masses, with a radius of 5โ6 solar radii. Hessels et al. state that the companion may be a "bloated main-sequence star, possibly still filling its Roche Lobe". Hessels et al. go on to speculate that gravitational radiation from the pulsar might be detectable by LIGO.
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- "The fastest pulsar spins at 716Hz; its equator spins at 24% the speed of light" | 2014-02-17 | 122 Upvotes 78 Comments
๐ Subutai โ Primary military strategist of Genghis Khan
Subutai (Classical Mongolian: Sรผbรผgรคtรคi or Sรผbรผ'รคtรคi; Tuvan: ะกาฏะฑัะดัะน, [sybษหdษj]; Modern Mongolian: ะกาฏะฑััะดัะน, Sรผbeedei. [sสbeหหdษ]; Chinese: ้ไธๅฐ 1175โ1248) was an Uriankhai general, and the primary military strategist of Genghis Khan and รgedei Khan. He directed more than 20 campaigns in which he conquered 32 nations and won 65 pitched battles, during which he conquered or overran more territory than any other commander in history. He gained victory by means of imaginative and sophisticated strategies and routinely coordinated movements of armies that were hundreds of kilometers away from each other. He is also remembered for devising the campaign that destroyed the armies of Hungary and Poland within two days of each other, by forces over 500 kilometers apart.
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- "Subutai โ Primary military strategist of Genghis Khan" | 2017-06-14 | 84 Upvotes 22 Comments