Random Articles (Page 3)
Have a deep view into what people are curious about.
🔗 Moon Illusion
The Moon illusion is an optical illusion which causes the Moon to appear larger near the horizon than it does higher up in the sky. It has been known since ancient times and recorded by various cultures. The explanation of this illusion is still debated.
Discussed on
- "Moon Illusion" | 2022-06-12 | 129 Upvotes 71 Comments
🔗 DNA origami
DNA origami is the nanoscale folding of DNA to create non-arbitrary two- and three-dimensional shapes at the nanoscale. The specificity of the interactions between complementary base pairs make DNA a useful construction material, through design of its base sequences. DNA is a well-understood material that is suitable for creating scaffolds that hold other molecules in place or to create structures all on its own.
DNA origami was the cover story of Nature on March 16, 2006. Since then, DNA origami has progressed past an art form and has found a number of applications from drug delivery systems to uses as circuitry in plasmonic devices; however, most applications remain in a concept or testing phase.
Discussed on
- "DNA origami" | 2016-12-22 | 37 Upvotes 5 Comments
🔗 Mars Monolith
The Mars monolith is a rectangular object (possibly a boulder) discovered on the surface of Mars. It is located near the bottom of a cliff, from which it likely fell. The Mars Reconnaissance Orbiter took pictures of it from orbit, roughly 180 miles (300 km) away.
Around the same time, the Phobos monolith made international news.
🔗 Gödel's Loophole
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."
Discussed on
- "Gödel's Loophole" | 2025-08-06 | 21 Upvotes 11 Comments
- "Gödel's Loophole" | 2023-07-24 | 21 Upvotes 4 Comments
- "Gödel's Loophole" | 2023-04-05 | 12 Upvotes 2 Comments
- "Gödel's Loophole" | 2023-01-20 | 10 Upvotes 1 Comments
- "Gödel's Loophole" | 2021-03-25 | 131 Upvotes 130 Comments
🔗 Oil Pipeline Pigs
In pipeline transportation, pigging is the practice of using devices known as pigs or scrapers to perform various maintenance operations. This is done without stopping the flow of the product in the pipeline. These devices are known as pigs because they scrape or clean just like a normal pig.
These operations include but are not limited to cleaning and inspecting the pipeline. This is accomplished by inserting the pig into a "pig launcher" (or "launching station") — an oversized section in the pipeline, reducing to the normal diameter. The launching station is then closed and the pressure-driven flow of the product in the pipeline is used to push the pig along down the pipe until it reaches the receiving trap — the "pig catcher" (or "receiving station").
Discussed on
- "Pigging" | 2023-10-21 | 222 Upvotes 80 Comments
- "Oil Pipeline Pigs" | 2014-07-28 | 12 Upvotes 3 Comments
🔗 The Theory of American Decline
American decline is a term used by various analysts to describe the diminishing power of the United States geopolitically, militarily, financially, economically, socially, and in health and the environment. There has been a debate between declinists, those who believe America is in decline, and exceptionalists, those who feel America is immortal.
Some analysts say that the U.S. was in decline long before Donald Trump ran for presidency; becoming the first presidential candidate to promote the idea that the U.S. was in decline. While others suggest the decline either stems from or has accelerated with Trump's foreign policy and the "country’s ongoing withdrawal from the global arena." According to Noam Chomsky, America's decline started at the end of WWII, dismissing the "remarkable rhetoric of the several years of triumphalism in the 1990s" as "mostly self-delusion".
Gallup's pollsters recently reported that worldwide approval of U.S. leadership has plunged from 48% in 2016 to a record low of 30% in 2018, in part due to the increasingly isolationist stances of Donald Trump. This drop places the U.S. a notch below China's 31% and leaving Germany as the most popular power with an approval of 41%. Michael Hudson describes financial pillar as paramount, resulting from bank-created money with compound interest and the inbuilt refusal to forgive debts as the fatal flaw.
China's challenging the U.S. for global predominance constitutes the core issue in the debate over the American decline.
Discussed on
- "The Theory of American Decline" | 2020-06-10 | 32 Upvotes 5 Comments
🔗 Microtome
A microtome (from the Greek mikros, meaning "small", and temnein, meaning "to cut") is a cutting tool used to produce extremely thin slices of material known as sections, with the process being termed microsectioning. Important in science, microtomes are used in microscopy for the preparation of samples for observation under transmitted light or electron radiation.
Microtomes use steel, glass or diamond blades depending upon the specimen being sliced and the desired thickness of the sections being cut. Steel blades are used to prepare histological sections of animal or plant tissues for light microscopy. Glass knives are used to slice sections for light microscopy and to slice very thin sections for electron microscopy. Industrial grade diamond knives are used to slice hard materials such as bone, teeth and tough plant matter for both light microscopy and for electron microscopy. Gem-quality diamond knives are also used for slicing thin sections for electron microscopy.
Microtomy is a method for the preparation of thin sections for materials such as bones, minerals and teeth, and an alternative to electropolishing and ion milling. Microtome sections can be made thin enough to section a human hair across its breadth, with section thickness between 50 nm and 100 μm.
Discussed on
- "Microtome" | 2024-08-27 | 16 Upvotes 5 Comments
🔗 Effects of Stress on Memory
The effects of stress on memory include interference with a person's capacity to encode memory and the ability to retrieve information. Stimuli, like stress, improved memory when it was related to learning the subject. During times of stress, the body reacts by secreting stress hormones into the bloodstream. Stress can cause acute and chronic changes in certain brain areas which can cause long-term damage. Over-secretion of stress hormones most frequently impairs long-term delayed recall memory, but can enhance short-term, immediate recall memory. This enhancement is particularly relative in emotional memory. In particular, the hippocampus, prefrontal cortex and the amygdala are affected. One class of stress hormone responsible for negatively affecting long-term, delayed recall memory is the glucocorticoids (GCs), the most notable of which is cortisol. Glucocorticoids facilitate and impair the actions of stress in the brain memory process. Cortisol is a known biomarker for stress. Under normal circumstances, the hippocampus regulates the production of cortisol through negative feedback because it has many receptors that are sensitive to these stress hormones. However, an excess of cortisol can impair the ability of the hippocampus to both encode and recall memories. These stress hormones are also hindering the hippocampus from receiving enough energy by diverting glucose levels to surrounding muscles.
Stress affects many memory functions and cognitive functioning of the brain. There are different levels of stress and the high levels can be intrinsic or extrinsic. Intrinsic stress level is triggered by a cognitive challenge whereas extrinsic can be triggered by a condition not related to a cognitive task. Intrinsic stress can be acutely and chronically experienced by a person. The varying effects of stress on performance or stress hormones are often compared to or known as "inverted-u" which induce areas in learning, memory and plasticity. Chronic stress can affect the brain structure and cognition.
Studies considered the effects of both intrinsic and extrinsic stress on memory functions, using for both of them Pavlovian conditioning and spatial learning. In regard to intrinsic memory functions, the study evaluated how stress affected memory functions that was triggered by a learning challenge. In regard to extrinsic stress, the study focused on stress that was not related to cognitive task but was elicited by other situations. The results determined that intrinsic stress was facilitated by memory consolidation process and extrinsic stress was determined to be heterogeneous in regard to memory consolidation. Researchers found that high stress conditions were a good representative of the effect that extrinsic stress can cause on memory functioning. It was also proven that extrinsic stress does affect spatial learning whereas acute extrinsic stress does not.
Discussed on
- "Effects of Stress on Memory" | 2024-12-10 | 19 Upvotes 5 Comments
🔗 Rolling Coal
Rolling coal (also spelled rollin' coal) is the practice of modifying a diesel engine to emit large amounts of black or grey sooty exhaust fumes—diesel fuel that has not undergone complete combustion.
Rolling coal is a form of anti-environmentalism. Such modifications may include the intentional removal of the particulate filter. Practitioners often additionally modify their vehicles by installing smoke switches, large exhausts, and smoke stacks. Modifications to a vehicle to enable rolling coal may cost from US$200 to US$5,000.
Discussed on
- "Rolling Coal" | 2024-05-11 | 10 Upvotes 2 Comments
🔗 Sputnik virophage
Sputnik virophage (from Russian cпутник "satellite", Latin "virus" and Greek φάγειν phagein "to eat") is a subviral agent that reproduces in amoeba cells that are already infected by a certain helper virus; Sputnik uses the helper virus's machinery for reproduction and inhibits replication of the helper virus.
Viruses like Sputnik that depend on co-infection of the host cell by helper viruses are known as satellite viruses. At its discovery in a Paris water-cooling tower in 2008 Sputnik was the first known satellite virus that inhibited replication of its helper virus and thus acted as a parasite of that virus. In analogy to the term bacteriophage it was called a virophage. However, the usage of this term and the relationship between virophages and classical satellite viruses remain controversial.
Sputnik virophages were found infecting giant viruses of Mimiviridae group A. However, they are able to grow in amoebae infected by Mimiviridae of any of the groups A, B, and C.
Discussed on
- "Sputnik virophage" | 2019-08-21 | 15 Upvotes 5 Comments