Random Articles (Page 6)
Have a deep view into what people are curious about.
🔗 Biosphere 2
Biosphere 2 is an American Earth system science research facility located in Oracle, Arizona. Its mission is to serve as a center for research, outreach, teaching, and lifelong learning about Earth, its living systems, and its place in the universe. It is a 3.14-acre (1.27-hectare) structure originally built to be an artificial, materially closed ecological system, or vivarium. It remains the largest closed ecological system ever created.
Constructed between 1987 and 1991, Biosphere 2 was originally meant to demonstrate the viability of closed ecological systems to support and maintain human life in outer space as a substitute for Earth's biosphere. It was designed to explore the web of interactions within life systems in a structure with different areas based on various biological biomes. In addition to the several biomes and living quarters for people, there was an agricultural area and work space to study the interactions between humans, farming, technology and the rest of nature as a new kind of laboratory for the study of the global ecology. Its mission was a two-year closure experiment with a crew of eight humans ("biospherians"). Long-term it was seen as a precursor to gaining knowledge about the use of closed biospheres in space colonization. As an experimental ecological facility it allowed the study and manipulation of a mini biospheric system without harming Earth's biosphere.
Its seven biome areas were a 1,900-square-meter (20,000 sq ft) rainforest, an 850-square-meter (9,100 sq ft) ocean with a coral reef, a 450-square-meter (4,800 sq ft) mangrove wetlands, a 1,300-square-metre (14,000 sq ft) savannah grassland, a 1,400-square-meter (15,000 sq ft) fog desert, and two anthropogenic biomes: a 2,500-square-meter (27,000 sq ft) agricultural system and a human habitat with living spaces, laboratories and workshops. Below ground was an extensive part of the technical infrastructure. Heating and cooling water circulated through independent piping systems and passive solar input through the glass space frame panels covering most of the facility, and electrical power was supplied into Biosphere 2 from an onsite natural gas energy center.
Biosphere 2 was only used twice for its original intended purposes as a closed-system experiment: once from 1991 to 1993, and the second time from March to September 1994. Both attempts ran into problems including low amounts of food and oxygen, die-offs of many animals and plants included in the experiment (though this was anticipated since the project used a strategy of deliberately "species-packing" anticipating losses as the biomes developed), group dynamic tensions among the resident crew, outside politics, and a power struggle over management and direction of the project. Nevertheless, the closure experiments set world records in closed ecological systems, agricultural production, health improvements with the high nutrient and low caloric diet the crew followed, and insights into the self-organization of complex biomic systems and atmospheric dynamics. The second closure experiment achieved total food sufficiency and did not require injection of oxygen.
In June 1994, during the middle of the second experiment, the managing company, Space Biosphere Ventures, was dissolved, and the facility was left in limbo. Columbia University assumed management of the facility in 1995 and used it to run experiments until 2003. It then appeared to be in danger of being demolished to make way for housing and retail stores, but was taken over for research by the University of Arizona in 2007. The University of Arizona took full ownership of the structure in 2011.
Discussed on
- "Biosphere 2" | 2023-05-26 | 100 Upvotes 50 Comments
🔗 Kei Car
Kei car (or keijidōsha, kanji: 軽自動車, "light automobile", pronounced [keːdʑidoːɕa]), known variously outside Japan as Japanese city car, ultramini, or Japanese microcar, is the Japanese vehicle category for the smallest highway-legal passenger cars. Similar Japanese categories exist for microvans, and kei trucks. These vehicles are most often the Japanese equivalent of the EU A-segment (city cars).
The kei-car category was created by the Japanese government in 1949, and the regulations have been revised several times since. These regulations specify a maximum vehicle size, engine capacity, and power output, so that owners may enjoy both tax and insurance benefits. In most rural areas they are also exempted from the requirement to certify that adequate parking is available for the vehicle.
Kei cars have become very successful in Japan, consisting of over one-third of domestic new-car sales in fiscal 2016, despite dropping from a record 40% market share in 2013, after the government increased the kei-car tax by 50% in 2014. In 2018, seven of the 10 top-selling models were kei cars, including the top four, all boxy passenger vans: Honda N-Box, Suzuki Spacia, Nissan Dayz, and Daihatsu Tanto. Isuzu is the only manufacturer that has never offered a kei-sized vehicle for either private ownership or commercial trucks and microvans.
In export markets, though, the genre is generally too specialized and too small for most models to be profitable. Notable exceptions exist, though, for instance the Suzuki Alto and Jimny models, which were exported consistently from around 1980. Kei cars are not only popular with the elderly, but they are also popular with youths because of their affordability.
Nearly all kei cars have been designed and manufactured in Japan, but a version of the French-made Smart was briefly imported and officially classified as a kei car, and since then, the British Caterham 7 160 has also received such classification.
Discussed on
- "Kei Car" | 2021-09-04 | 139 Upvotes 179 Comments
🔗 Gruen transfer
In shopping mall design, the Gruen transfer (also known as the Gruen effect) is the moment when consumers enter a shopping mall or store and, surrounded by an intentionally confusing layout, lose track of their original intentions, making consumers more susceptible to make impulse buys. It is named for Austrian architect Victor Gruen, who disavowed such manipulative techniques.
Discussed on
- "Gruen Transfer" | 2024-06-11 | 134 Upvotes 76 Comments
- "Gruen transfer" | 2018-04-15 | 105 Upvotes 58 Comments
🔗 Archaeal Richmond Mine Acidophilic Nanoorganisms
Archaeal Richmond Mine acidophilic nanoorganisms (ARMAN) were first discovered in an extremely acidic mine located in northern California (Richmond Mine at Iron Mountain) by Brett Baker in Jill Banfield's laboratory at the University of California Berkeley. These novel groups of archaea named ARMAN-1, ARMAN-2 (Candidatus Micrarchaeum acidiphilum ARMAN-2 ), and ARMAN-3 were missed by previous PCR-based surveys of the mine community because the ARMANs have several mismatches with commonly used PCR primers for 16S rRNA genes. Baker et al. detected them in a later study using shotgun sequencing of the community. The three groups were originally thought to represent three unique lineages deeply branched within the Euryarchaeota, a subgroup of the Archaea. However, this has been revised, based on more complete archaeal genomic tree, that they belong to a super phylum named DPANN. The ARMAN groups now comprise deeply divergent phyla named Micrarchaeota and Parvarchaeota. Their 16S rRNA genes differ by as much as 17% between the three groups. Prior to their discovery all of the Archaea shown to be associated with Iron Mountain belonged to the order Thermoplasmatales (e.g., Ferroplasma acidarmanus).
Discussed on
- "Archaeal Richmond Mine Acidophilic Nanoorganisms" | 2020-01-13 | 17 Upvotes 1 Comments
🔗 Kullback–Leibler Divergence
In mathematical statistics, the Kullback–Leibler divergence (also called relative entropy and I-divergence), denoted , is a type of statistical distance: a measure of how one probability distribution P is different from a second, reference probability distribution Q. A simple interpretation of the KL divergence of P from Q is the expected excess surprise from using Q as a model when the actual distribution is P. While it is a distance, it is not a metric, the most familiar type of distance: it is not symmetric in the two distributions (in contrast to variation of information), and does not satisfy the triangle inequality. Instead, in terms of information geometry, it is a type of divergence, a generalization of squared distance, and for certain classes of distributions (notably an exponential family), it satisfies a generalized Pythagorean theorem (which applies to squared distances).
In the simple case, a relative entropy of 0 indicates that the two distributions in question have identical quantities of information. Relative entropy is a nonnegative function of two distributions or measures. It has diverse applications, both theoretical, such as characterizing the relative (Shannon) entropy in information systems, randomness in continuous time-series, and information gain when comparing statistical models of inference; and practical, such as applied statistics, fluid mechanics, neuroscience and bioinformatics.
Discussed on
- "Kullback–Leibler Divergence" | 2023-08-21 | 177 Upvotes 74 Comments
🔗 Botanical Sexism
Botanical sexism is a term coined by horticulturist Tom Ogren to describe the planting of male plants instead of female plants of certain dioecious species including: willows, poplars, aspens, ashes, silver maples, pistache, mulberry, pepper tree and other woody plants such as junipers, yew pines, fern pines, wax myrtles, alpine currants, plum yews, and yews According to Ogren, pollen allergies have been amplified due to the planting in urban areas of male clones which increases the amount of pollen in the air. Male plants are commonly used in urban areas because plants with female flowers produce fruits and flowers that litter the landscape. The planting of more female plants would decrease the overall amount of pollen since they do not produce pollen and remove pollen from the air for pollination. The theory has existed since at least the 2000s. Biological sexism is used in the Ogren Plant Allergy Scale (OPALS), which has been adopted by the United States Department of Agriculture. Botanical sexism has found some scientific acceptance as a reason for increased allergies and asthma; however, other scientists have also been critical of it, stating that it only applies to certain trees and is not as widespread as Ogren alleges.
Discussed on
- "Botanical Sexism" | 2023-06-24 | 39 Upvotes 6 Comments
🔗 The Iron Law of Wages
The iron law of wages is a proposed law of economics that asserts that real wages always tend, in the long run, toward the minimum wage necessary to sustain the life of the worker. The theory was first named by Ferdinand Lassalle in the mid-nineteenth century. Karl Marx and Friedrich Engels attribute the doctrine to Lassalle (notably in Marx's 1875 Critique of the Gotha Program), the idea to Thomas Malthus's An Essay on the Principle of Population, and the terminology to Goethe's "great, eternal iron laws" in Das Göttliche.
It was coined in reference to the views of classical economists such as David Ricardo's Law of rent, and the competing population theory of Thomas Malthus. It held that the market price of labour would always, or almost always, tend toward the minimum required for the subsistence of the labourers, reducing as the working population increased and vice versa. Ricardo believed that happened only under particular conditions.
Discussed on
- "The Iron Law of Wages" | 2020-08-20 | 26 Upvotes 35 Comments
🔗 Berserker Hypothesis
The berserker hypothesis, also known as the deadly probes scenario, is the idea that humans have not yet detected intelligent alien life in the universe because it has been systematically destroyed by a series of lethal Von Neumann probes. The hypothesis is named after the Berserker series of novels (1963-2005) written by Fred Saberhagen.
The hypothesis has no single known proposer, and instead is thought to have emerged over time in response to the Hart–Tipler conjecture, or the idea that an absence of detectable Von Neumann probes is contrapositive evidence that no intelligent life exists outside of the Sun's Solar System. According to the berserker hypothesis, an absence of such probes is not evidence of life's absence, since interstellar probes could "go berserk" and destroy other civilizations, before self-destructing.
In his 1983 paper "The Great Silence", astronomer David Brin summarized the frightening implications of the berserker hypothesis: it is entirely compatible with all the facts and logic of the Fermi paradox, but would mean that there exists no intelligent life left to be discovered. In the worst-case scenario, humanity has already alerted others to its existence, and is next in line to be destroyed.
There is no need to struggle to suppress the elements of the Drake equation in order to explain the Great Silence, nor need we suggest that no [intelligent aliens] anywhere would bear the cost of interstellar travel. It need only happen once for the results of this scenario to become the equilibrium conditions in the Galaxy. We would not have detected extra-terrestrial radio traffic – nor would any [intelligent aliens] have ever settled on Earth – because all were killed shortly after discovering radio.
Discussed on
- "Berserker Hypothesis" | 2023-07-14 | 12 Upvotes 8 Comments
🔗 Nothwithstanding Clause lets Canadian Provinces violate Constitutional rights
Section 33 of the Canadian Charter of Rights and Freedoms is part of the Constitution of Canada. It is commonly known as the notwithstanding clause (French: clause dérogatoire or clause nonobstant), sometimes referred to as the override power, and it allows Parliament or provincial legislatures to temporarily override sections 2 and 7–15 of the Charter.
Discussed on
- "Nothwithstanding Clause lets Canadian Provinces violate Constitutional rights" | 2023-05-31 | 21 Upvotes 1 Comments
🔗 The Pip
The Pip is the nickname given by radio listeners to a shortwave radio station that broadcasts on the frequency 5448 kHz by day, and 3756 kHz during the night. It broadcasts short, repeated beeps at a rate of around 50 per minute, for 24 hours per day. The beep signal is occasionally interrupted by voice messages in Russian. The Pip has been active since around 1985, when its distinctive beeping sound was first recorded by listeners.
The station is commonly referred to as "The Pip" among English-speaking radio listeners. In Russia, it is known as Капля (Kaplya) "the drop". While its official name or callsign is not known, some of the voice transmissions begin with the code 8S1Shch (Cyrillic: 8С1Щ), which is generally considered to be the name of the station. However, this code may not be a callsign, but instead serve some other purpose. Radioscanner.ru identifies the owner of this station as a North-Caucasian military district communication center with callsign "Akacia" (ex-72nd communication center, Russian "72 узел связи штаба СКВО").
Discussed on
- "The Pip" | 2015-12-02 | 120 Upvotes 24 Comments