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🔗 International relations 🔗 Soviet Union 🔗 Russia 🔗 Russia/politics and law of Russia 🔗 Finland

The Karelian question or Karelian issue (Finnish: Karjala-kysymys, Swedish: Karelska frågan) is a dispute in Finnish politics over whether to try to regain control over eastern Finnish Karelia and other territories ceded to the Soviet Union in the Winter War and the Continuation War. Despite the name "Karelian question", the term may refer also to the return of Petsamo, ceded parts of Salla and Kuusamo, and four islands in the Gulf of Finland. Sometimes the phrase "debate on the return of the ceded territories" (luovutettujen alueiden palautuskeskustelu, Swedish: debatten om tillbakalämningen av de avträdda territorierna) is used. The Karelian question remains a matter of public debate rather than a political issue.

🔗 Environment 🔗 Economics

In economics, the Jevons paradox (; sometimes Jevons effect) occurs when technological progress or government policy increases the efficiency with which a resource is used (reducing the amount necessary for any one use), but the rate of consumption of that resource rises due to increasing demand. The Jevons paradox is perhaps the most widely known paradox in environmental economics. However, governments and environmentalists generally assume that efficiency gains will lower resource consumption, ignoring the possibility of the paradox arising.

In 1865, the English economist William Stanley Jevons observed that technological improvements that increased the efficiency of coal-use led to the increased consumption of coal in a wide range of industries. He argued that, contrary to common intuition, technological progress could not be relied upon to reduce fuel consumption.

The issue has been re-examined by modern economists studying consumption rebound effects from improved energy efficiency. In addition to reducing the amount needed for a given use, improved efficiency also lowers the relative cost of using a resource, which increases the quantity demanded. This counteracts (to some extent) the reduction in use from improved efficiency. Additionally, improved efficiency increases real incomes and accelerates economic growth, further increasing the demand for resources. The Jevons paradox occurs when the effect from increased demand predominates, and improved efficiency increases the speed at which resources are used.

Considerable debate exists about the size of the rebound in energy efficiency and the relevance of the Jevons paradox to energy conservation. Some dismiss the paradox, while others worry that it may be self-defeating to pursue sustainability by increasing energy efficiency. Some environmental economists have proposed that efficiency gains be coupled with conservation policies that keep the cost of use the same (or higher) to avoid the Jevons paradox. Conservation policies that increase cost of use (such as cap and trade or green taxes) can be used to control the rebound effect.

🔗 History 🔗 Middle Ages 🔗 Middle Ages/History

The Nine Worthies are nine historical, scriptural, and legendary personages who personify the ideals of chivalry established in the Middle Ages, whose lives were deemed a valuable study for aspirants to chivalric status. All were commonly referred to as 'Princes', regardless of their historical titles. In French they are called Les Neuf Preux or "Nine Valiants", giving a more specific idea of the moral virtues they exemplified: those of soldierly courage and generalship. In Italy they are i Nove Prodi.

The Nine Worthies include three pagans (Hector, Alexander the Great and Julius Caesar), three Jews (Joshua, David and Judas Maccabeus) and three Christians (King Arthur, Charlemagne and Godfrey of Bouillon).

Wikipedia offers free copies of all available content to interested users. These databases can be used for mirroring, personal use, informal backups, offline use or database queries (such as for Wikipedia:Maintenance). All text content is licensed under the Creative Commons Attribution-ShareAlike 4.0 License (CC-BY-SA), and most is additionally licensed under the GNU Free Documentation License (GFDL). Images and other files are available under different terms, as detailed on their description pages. For our advice about complying with these licenses, see Wikipedia:Copyrights.

Some of the many ways to read Wikipedia while offline:

• Kiwix: (§ Kiwix) – index of images (2024)
• XOWA: (§ XOWA) – index of images (2015)
• WikiTaxi: § WikiTaxi (for Windows)
• aarddict: § Aard Dictionary / Aard 2
• BzReader: § BzReader and MzReader (for Windows)
• WikiFilter: § WikiFilter
• Wikipedia on rockbox: § Wikiviewer for Rockbox
• Selected Wikipedia articles as a printed document: Help:Printing

Some of them are mobile applications – see "List of Wikipedia mobile applications".

🔗 Algae

Valonia ventricosa, also known as bubble algae or sailor's eyeballs is a species of alga found in oceans throughout the world in tropical and subtropical regions. It is one of the largest – if not the largest – unicellular organisms.

🔗 Mathematics

In geometric topology, the Clifford torus is the simplest and most symmetric flat embedding of the cartesian product of two circles S¹_a and S¹_b (in the same sense that the surface of a cylinder is "flat"). It is named after William Kingdon Clifford. It resides in R⁴, as opposed to in R³. To see why R⁴ is necessary, note that if S¹_a and S¹_b each exist in their own independent embedding spaces R²_a and R²_b, the resulting product space will be R⁴ rather than R³. The historically popular view that the cartesian product of two circles is an R³ torus in contrast requires the highly asymmetric application of a rotation operator to the second circle, since that circle will only have one independent axis z available to it after the first circle consumes x and y.

Stated another way, a torus embedded in R³ is an asymmetric reduced-dimension projection of the maximally symmetric Clifford torus embedded in R⁴. The relationship is similar to that of projecting the edges of a cube onto a sheet of paper. Such a projection creates a lower-dimensional image that accurately captures the connectivity of the cube edges, but also requires the arbitrary selection and removal of one of the three fully symmetric and interchangeable axes of the cube.

If S¹_a and S¹_b each has a radius of ${\displaystyle \textstyle {\sqrt {1/2}}}$, their Clifford torus product will fit perfectly within the unit 3-sphere S³, which is a 3-dimensional submanifold of R⁴. When mathematically convenient, the Clifford torus can be viewed as residing inside the complex coordinate space C², since C² is topologically equivalent to R⁴.

The Clifford torus is an example of a square torus, because it is isometric to a square with opposite sides identified. It is further known as a Euclidean 2-torus (the "2" is its topological dimension); figures drawn on it obey Euclidean geometry as if it were flat, whereas the surface of a common "doughnut"-shaped torus is positively curved on the outer rim and negatively curved on the inner. Although having a different geometry than the standard embedding of a torus in three-dimensional Euclidean space, the square torus can also be embedded into three-dimensional space, by the Nash embedding theorem; one possible embedding modifies the standard torus by a fractal set of ripples running in two perpendicular directions along the surface.

In mathematics and computing, Fibonacci coding is a universal code which encodes positive integers into binary code words. It is one example of representations of integers based on Fibonacci numbers. Each code word ends with "11" and contains no other instances of "11" before the end.

The Fibonacci code is closely related to the Zeckendorf representation, a positional numeral system that uses Zeckendorf's theorem and has the property that no number has a representation with consecutive 1s. The Fibonacci code word for a particular integer is exactly the integer's Zeckendorf representation with the order of its digits reversed and an additional "1" appended to the end.

🔗 Biology 🔗 Science Fiction 🔗 Chemistry

Hypothetical types of biochemistry are forms of biochemistry speculated to be scientifically viable but not proven to exist at this time. The kinds of living organisms currently known on Earth all use carbon compounds for basic structural and metabolic functions, water as a solvent, and DNA or RNA to define and control their form. If life exists on other planets or moons, it may be chemically similar; it is also possible that there are organisms with quite different chemistries—for instance, involving other classes of carbon compounds, compounds of another element, or another solvent in place of water.

The possibility of life-forms being based on "alternative" biochemistries is the topic of an ongoing scientific discussion, informed by what is known about extraterrestrial environments and about the chemical behaviour of various elements and compounds. It is of interest in synthetic biology and is also a common subject in science fiction.

The element silicon has been much discussed as a hypothetical alternative to carbon. Silicon is in the same group as carbon on the periodic table and, like carbon, it is tetravalent. Hypothetical alternatives to water include ammonia, which, like water, is a polar molecule, and cosmically abundant; and non-polar hydrocarbon solvents such as methane and ethane, which are known to exist in liquid form on the surface of Titan.

🔗 Medicine 🔗 Medicine/Pulmonology 🔗 Physiology 🔗 Scuba diving 🔗 Physiology/respiratory

Liquid breathing is a form of respiration in which a normally air-breathing organism breathes an oxygen-rich liquid (such as a perfluorocarbon), rather than breathing air.

This requires certain physical properties such as respiratory gas solubility, density, viscosity, vapor pressure, and lipid solubility which some, but not all, perfluorochemicals (perfluorocarbon) have. Thus, it is critical to choose the appropriate PFC for a specific biomedical application, such as liquid ventilation, drug delivery or blood substitutes. The physical properties of PFC liquids vary substantially; however, the one common property is their high solubility for respiratory gases. In fact, these liquids carry more oxygen and carbon dioxide than blood.

In theory, liquid breathing could assist in the treatment of patients with severe pulmonary or cardiac trauma, especially in pediatric cases. Liquid breathing has also been proposed for use in deep diving and space travel. Despite some recent advances in liquid ventilation, a standard mode of application has not yet been established.