In telecommunications and computer networking, multiplexing (sometimes contracted to muxing) is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource - a physical transmission medium. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910. The multiplexed signal is transmitted over a communication channel such as a cable. The multiplexing divides the capacity of the communication channel into several logical channels, one for each message signal or data stream to be transferred. A reverse process, known as demultiplexing...

Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes , placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth. The common name "lamprey" is probably derived from Latin lampetra, which may mean "stone licker" (lambere "to lick" + petra "stone"), though the etymology is uncertain. Lamprey is sometimes seen for the plural form.There are about 38 known extant species of lampreys and five known extinct species. They are classified in three families: two species-poor families in the Southern Hemisphere and one speciose family in the Northern Hemisphere; phylogenetic studies indicate a mid-Mesozoic divergence for all three, underlying the separation of Laurasia and Gondwanaland. The occurrence of modern lampreys only since the Mesozoic (with significant genus & species radiations only...

A dolmen () or portal tomb is a type of single-chamber megalithic tomb, usually consisting of two or more upright megaliths supporting a large flat horizontal capstone or "table". Most date from the early Neolithic period (4000–3000 BCE) and were sometimes covered with earth or smaller stones to form a tumulus (burial mound). Small pad-stones may be wedged between the cap and supporting stones to achieve a level appearance. In many instances, the covering has eroded away, leaving only the stone "skeleton". The Korean Peninsula is home to the world's highest concentration of dolmens, including "cemeteries" consisting of 30–100 examples located in close proximity to each other; with over 35,000 dolmens, Korea alone (for unknown reasons) accounts for approximately 40% of the global total. History It remains unclear when, why and by whom the earliest dolmens were made. The oldest known are found in Western Europe, dating from c. 7,000 years ago. Archaeologists still do not know who erected these dolmens, which makes it difficult to know why they did it. They are generally all regarded as tombs or burial chambers...

The Trifid Nebula (catalogued as Messier 20 or M20 and as NGC 6514) is an H II region in the north-west of Sagittarius in a star-forming region in the Milky Way's Scutum-Centaurus Arm. It was discovered by Charles Messier on June 5, 1764. Its name means 'three-lobe'. The object is an unusual combination of an open cluster of stars, an emission nebula (the relatively dense, reddish-pink portion), a reflection nebula (the mainly NNE blue portion), and a dark nebula (the apparent 'gaps' in the former that cause the trifurcated appearance, also designated Barnard 85). Viewed through a small telescope, the Trifid Nebula is a bright and peculiar object, and is thus a perennial favorite of amateur astronomers.The most massive star that has formed in this region is HD 164492A, an O7.5III star with a mass more than 20 times the mass of the Sun. This star is surrounded by a cluster of approximately 3100 young stars. Characteristics The Trifid Nebula was the subject of an investigation by astronomers using the Hubble Space Telescope in 1997, using filters that isolate emission from hydrogen atoms,...

The pulmonary circulation is a division of the circulatory system in all vertebrates. The circuit begins with deoxygenated blood returned from the body to the right atrium of the heart where it is pumped out from the right ventricle to the lungs. In the lungs the blood is oxygenated and returned to the left atrium to complete the circuit.The other division of the circulatory system is the systemic circulation that begins with receiving the oxygenated blood from the pulmonary circulation into the left atrium. From the atrium the oxygenated blood enters the left ventricle where it is pumped out to the rest of the body, returning as deoxygenated blood back to the pulmonary circulation. The blood vessels of the pulmonary circulation are the pulmonary arteries and the pulmonary veins. A separate circulatory circuit known as the bronchial circulation supplies oxygenated blood to the tissue of the larger airways of the lung. Structure De-oxygenated blood leaves the heart, goes to the lungs, and then enters back into the heart. De-oxygenated blood leaves through the right ventricle through the pulmonary artery....

Diatomic molecules (from Greek di- 'two') are molecules composed of only two atoms, of the same or different chemical elements. If a diatomic molecule consists of two atoms of the same element, such as hydrogen (H2) or oxygen (O2), then it is said to be homonuclear. Otherwise, if a diatomic molecule consists of two different atoms, such as carbon monoxide (CO) or nitric oxide (NO), the molecule is said to be heteronuclear. The bond in a homonuclear diatomic molecule is non-polar. The only chemical elements that form stable homonuclear diatomic molecules at standard temperature and pressure (STP) (or typical laboratory conditions of 1 bar and 25 °C) are the gases hydrogen (...

Imperial Diet means the highest representative assembly in an empire, notably: Imperial Diet (Holy Roman Empire), the general assembly of the Imperial Estates of the Holy Roman Empire (962–1806) National Diet, the current legislature of Japan (1889–) Imperial Diet (Austria), short-lived body that represented the non-Hungarian lands of the Austrian Empire (1848–1849)See also Diet (assembly) Reichstag (disambiguation)

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Massaman curry (Thai: แกงมัสมั่น, RTGS: kaeng matsaman, pronounced [mát.sa.màn] (listen)) is a rich, flavourful, and mildly spicy Thai curry. It is a fusion dish, combining ingredients from Persia, the Indian subcontinent, and the Malay Archipelago (e.g., cardamom, cinnamon, cloves, star anise, cumin, bay leaves, nutmeg, and mace) with ingredients more commonly used in native Thai cuisine (e.g., chili peppers, coriander, lemongrass, galangal, white pepper, shrimp paste, shallots, and garlic) to make massaman curry paste. The substance of the dish is usually based on chicken or other meat, potatoes, onions, and peanuts. The richness comes from the coconut milk and cream used as a base, as for many Thai curries. In 2011, CNNGo ranked massaman curry as the number one most delicious food in an article titled "World's 50 most delicious foods". However, by a reader's survey...

Papakōlea Beach (also known as Green Sand Beach or Mahana Beach) is a green sand beach located near South Point, in the Kaʻū district of the island of Hawaiʻi. It is one of only four green sand beaches in the world, the others being Talofofo Beach, Guam; Punta Cormorant on Floreana Island in the Galapagos Islands; and Hornindalsvatnet, Norway. It gets its distinctive coloring from olivine sand eroded out of the enclosing volcanic cone (tuff ring). Characteristics Papakōlea Beach is located in a bay half circled by Puʻu Mahana, a tuff ring formed over 49,000 years ago and associated with the southwest rift of Mauna Loa. Unlike cinder cones, tuff rings consist mostly of volcanic ash produced by violent interactions of magma with groundwater (Diamond Head, on the Island of Oahu, is another example of a tuff ring). Since its last eruption, the tuff ring has partially collapsed and been partially eroded by the ocean. The beach is sometimes named after the tuff ring, and sometimes after the area of land called Papakōlea, which comes from papa kōlea, which means plover flats in the Hawaiian language. Papakōlea...