AcharyaChanakya/simple-wikipedia huggingface dataset:
Isotope electrochemistry is a field within electrochemistry concerned with various topics like electrochemical separation of isotopes, electrochemical estimation of isotopic exchange equilibrium constants, electrochemical kinetic isotope effect, electrochemical isotope sensors, etc.
Chemists are actively working in this area. It overlaps with many other chemistry areas of both theoretical and practical importance like nuclear engineering, electrochemical technology, geochemistry, sensors and instrumentation.
Where Did the Feeling Go?
"Where Did The Feeling Go?" is a song by Australian soft rock duo "Air Supply". In 1989, American singer Selena had done a cover version of the song. The song was not released until after her murder. The single was released on the in 1997. Selena's version peaked at number 88 on the Canadian Hot 100 chart and number 26 on the Adult Top 40 chart.
These artists had done a cover as a tribute to Selena:
Is It the Beat?
Last Dance/The Hustle/On the Radio
A Boy Like That
"A Boy Like That" is a popular Broadway song. "A Boy Like That" (originally "A Boy Like That/I Have A Love") was written by Leonard Bernstein and Stephen Sondheim for the musical play, "The West Side Story" (1957). The song was performed by Chita Rivera (Anita) and Carol Lawrence (Maria). In the 1960 movie version the roles were played by Rita Moreno and Natalie Wood, but the songs were dubbed by Betty Wand and Marni Nixon (as both Anita and Maria).
In 1995, after attending the Grammy Awards, Selena was asked to participate in the AIDS Project Los Angeles. She accepted because she had loved to do charity work and give back to her community, for which she was famous for being "down-to-Earth". Selena recorded the song as a rhythm and blues, funk song. It was released after Selena was murdered for the various artists album in 1997.
Sukiyaki (song)
"Ue o Muite Arukō" () is a song by Japanese singer Kyu Sakamoto. It was dubbed "Sukiyaki" in popular culture. The song peaked on the "Billboard" Hot 100 charts in the United States in 1963, and was the only Japanese language song to do so. The song sold over 13 million copies internationally.
Biophysical chemistry
Biophysical chemistry is the study of biological systems. It looks for explanations of the various phenomena in biological systems in terms of either the molecules that make up the system or the supra-molecular structure of these systems.
Biophysical chemists use various tools used in physical chemistry to probe the structure of biological systems. These tools include spectroscopic methods like nuclear magnetic resonance (NMR) and X-ray diffraction. For example, the Nobel Prize in Chemistry in 2009 was based on x-ray diffraction studies of ribosomes.
Biophysical chemists study protein structure and the functional structure of cell membranes. For example, enzyme action can be explained in terms of the shape of a pocket in the protein molecule that matches the shape of the substrate molecule or its modification due to binding of a metal ion. Similarly, biophysical chemists study the structure and function of the biomembranes using model supramolecular structures. These include liposomes or phospholipid vesicles of different compositions and sizes.
The oldest well-known institute for biophysical chemistry is Max Planck Institute for Biophysical Chemistry in Göttingen. The Biophysics Department of King's College London is where the X-ray crystallography studies of DNA was done in the early 1950s.
Bioinorganic chemistry
Bioinorganic chemistry studies the role of metals in biology. It also studies natural phenomena such as the behaviour of metalloproteins and artificially introduced metals in medicine and toxicology. Many biological processes such as respiration depend on some inorganic molecules. Bioinorganic chemistry also includes the study of inorganic models or mimics that imitate the way metalloproteins work.
It is a mix of biochemistry and inorganic chemistry. Bioinorganic chemistry studies the implications for biology of electron-transfer proteins, substrate bindings and activation, atom and group chemistry as well as metal properties.
Paul Ehrlich used organoarsenic (“arsenicals”) for the treatment of syphilis. This demonstrated the relevance of metals, or at least metalloids, to medicine. Then Rosenberg discovered the anti-cancer activity of cisplatin (cis-PtCl(NH)). The first protein ever crystallized was urease. This has nickel at its active site. Vitamin B, the cure for pernicious anemia, was shown by crystallography by Dorothy Hodgkin to have a cobalt atom in a corrin macrocycle. The Watson-Crick structure for DNA demonstrated the key structural role played by phosphate-containing polymers.
Some areas of interest in research are:
Kōji
Kōji (麹 or こうじ) is a fermented food.
A mold called Aspergillus oryzae is added to rice, barley, or soy beans. This mold turns starch into sugar. Kōji is an ingredient in making many Japanese foods and drinks such as: sake, mirin, miso, vinegar, pickles, soy sauce, shōchū, and awamori.
Koji
Koji or kōji means:
In Japan, "Kōji" may mean:
Madea
Mabel "Madea" Simmons is a fictional African American character. "Madea" is played by Tyler Perry in drag clothing.
Madea was born in New Orleans, Louisiana on April 26, 1935. "Big Mabel" Murfy was the name of her mother. Frederick Simmons was the name of her father. Madea grew up with a strict mother who was also nurturing to Madea's emotions. At age 9, Madea was charged for petty theft. When Madea was 16 years of age, her parents moved to Atlanta, Georgia. There, she attended Booker T. Washington High School. She had tried out for cheerleading and became a cheerleader. By the time Madea was 17, she began going out to night clubs and house parties. Her parents allowed Madea to party at this age. Around this time, Madea became a stripper and was given the name "Delicious". At 18, Madea was charged with illegal gambling, check fraud and identity theft. Around this time, Madea had at least two or three children. She supported herself and her children by pool dancing, stripping and professional wrestling. Madea graduated her high school in May 1959. That night, she had an affair with Thoedure Leroy Brown (also known as "Mr. Brown"). Madea became pregnant and had given birth to Cora Jean Simmons Brown. However, in the movie Madea's Big Happy Family, Mr. Brown had a DNA test which confirmed that he was not the father. Madea was diagnosed with type one diabetes and depression in her early 20s. She had became a bitter women around this time.
Madea's appearance is an elderly women who is not afraid to threaten anybody with her pistol. Madea usually helps her family through life situations, struggles and helping her family cope with one another. She teaches them wisdom; which helps them in their everyday life. Madea is also a forceful women who teaches young adults to act mature. Madea has been locked up in prison several times. She has outlived several of her husbands and lives off of their life security checks. Madea uses bad language and tone to speak to her family when they are disrespectful. She also has a bad temper and bad way of dealing with anger. Madea is known to be half African American and quarter-Cherokee Indian. She likes going to the casino on Sunday, rather than going to the church. Although Madea does not read the bible, she uses it to manipulate situations in order to justify what she had done.
Royal ghost frog
The Royal ghost frog ("Heleophryne regis") is a species of frog in the Heleophrynidae family.
Its natural habitats are temperate forests, Mediterranean-type shrubby vegetation, and rivers.
Joey Tribbiani
Joey Tribbiani is a fictional character on American sitcom "Friends", portrayed by Matt LeBlanc. In the series, Joey is an actor, and plays "Dr. Drake Ramoray" on "Days Of Our Lives".
Doburoku
It is very easy to make at home with simple kitchen tools. However, this kind of sake is not legal to make at home in Japan.
Jagadguru Rambhadracharya Handicapped University
Jagadguru Rambhadracharya Handicapped University (or in short JRHU) (, ), is a university in Chitrakoot, Uttar Pradesh, India. It is the first university in India and the world which is only for disabled people. It was started on September 27, 2001 by Jagadguru Rambhadracharya. It is run by a trust named as "Jagadguru Rambhadracharya Viklang Shikshan Sansthan". The trust is responsible for all planned works of the university. It was created by a local law of the Uttar Pradesh Government, which was afterwards accepted as the Uttar Pradesh State Act 32 (2001) by the Uttar Pradesh legislature. This act assigned Jagadguru Rambhadracharya as the chancellor of this university for his entire life.
The university offers graduate, post-graduate and doctorate degrees in courses such as Sanskrit, Hindi, English, Sociology, Psychology, Fine Arts, Special education, Education, History, Culture & Archeology, Computer & Information Sciences, Vocational Education, Law, Economics, and Prosthetics and Orthotics. The university is planning to give courses in Ayurveda and Medical Sciences from 2013. The permission to enter into the university is limited to only four types of disabled students – those who are blind, or have difficulty in hearing, having difficulty in walking or having some mental illness, as defined in the Disability Act (1995) of the Government of India. Various degrees were given to 354 disabled students in the second graduation ceremony of the university which was held in March 2010. In the third graduation ceremony which was held in January 2011, 388 disabled students were given degrees. All the facilities in the university such as classrooms, hostel and laboratory etc. are disabled friendly.
Pons
The pons is part of the hindbrain, the ancient rear part of the brain. It acts as a bridge, and has nerve fibres connecting the cerebellum to the medulla oblongata. In humans it is above the medulla and below the midbrain.
Mainly, its function is to carry white fibres ("wiring") which conduct signals from the cerebrum down to the cerebellum and medulla, and tracts that carry the sensory signals up into the thalamus.
Dibutyl sebacate
Dibutyl sebacate (DBS) is an organic compound. It is used as a plasticizer. It is a dibutyl ester of sebacic acid. Its main use is to produce plastics. It can make cellulose acetate butyrate, cellulose acetate propionate, ethyl cellulose, polyvinyl butyral, polyvinyl chloride, polystyrene, and other plastics. These plastics are used in the food packaging industry, in medical devices, and in pharmaceutical applications. For example, it is used as a plasticizer for film coating of tablets, beads, and granules.
It is used make synthetic rubbers (especially nitrile rubber and neoprene). It is also used as a lubricant (something that reduces friction between moving surfaces) in shaving lotions, and a flavoring additive in non-alcoholic beverages, ice cream, ices, candy, and baked goods. DBS works well with a range of plastic materials. It has good properties at low temperatures, and helps plastics from being dissolved by oil. Dibutyl sebacate is also used as a desensitizer in Otto fuel II, a torpedo monopropellant.
DBS is also called Morflex, Kodaflex, polycizer, Proviplast 1944 and PX 404.
Habituation is a basic activity whereby an animal responds less to repeated stimuli. It is a primitive kind of learning.
The learning that underlies habituation is a basic process of biological systems. Animals do not need conscious motivation or awareness for it to occur. Habituation enables organisms to distinguish meaningful information from background stimuli.
Habituation occurs in all animals, as well as in the large protozoan "Stentor coeruleus". The decrease in responding is specific to the habituated stimulus. For example, if one was habituated to the taste of lemon, their responding would increase significantly when presented with the taste of lime.
Two factors that can influence habituation include the time between each stimulus, and the length of time the stimulus is presented. Shorter intervals and longer durations increase habituation, and "vice versa".
Habituation need not be conscious. For example, a short time after a person dresses, the stimulus clothing creates disappears from our nervous systems and we become unaware of it. In this way, habituation is used to ignore any continual stimulus. This sort of habituation can occur through changes in sensory nerves themselves, and through negative feedback from the brain to peripheral sensory organs.
Nasal consonant
A nasal consonant is a type of consonant produced with a lowered velum in the mouth, allowing air to come out through the nose, while the air is not allowed to pass through the mouth because something (like the tongue or the lips) is stopping it. Examples of nasal consonants in English are and , in words such as "nose" and "mouth".
Nearly all nasal consonants are nasal stops (or nasal continuants), where air comes out through the nose but not through the mouth, as it is blocked by the lips or tongue.
Most nasals are voiced, and, in fact, the nasal sounds and are among the most common sounds used in languages of the world. Voiceless nasals are used in a few languages, such as Burmese and Welsh.
In terms of acoustics, nasal stops are sonorants, meaning that they do not significantly stop the flow of air (as it can come out the nose). However, nasals are also stops in their articulation because the flow of air through the mouth is blocked completely. So nasal consonants sound both like sonorants and like obstruents.
Acoustically, nasal stops have bands of energy at around 200 and 2,000 Hz.
Examples of languages containing nasal consonants:
The voiced retroflex nasal is [ɳ] is a common sound in Indic languages.
The voiced palatal nasal [ɲ] is a common sound in European languages, such as: Spanish "ñ"; or French and Italian "gn"; or Catalan, Hungarian and Luganda "ny"; or Czech and Slovak "ň"; or Polish "ń"; or Occitan and Portuguese "nh"; or Serbian, Croatian, Bosnian and Montenegrin "nj".
English, German and Cantonese have , and . Tamil has its own different letters for the sounds , , , , and (ம,ந,ன,ண,ஞ,ங).
Catalan, Occitan, Spanish, and Italian have , , as phonemes, and and as allophones. (In several American dialects of Spanish, there is no palatal nasal but only a palatalized nasal, , as in English "canyon". In Brazilian Portuguese nh is frequently pronounced as a nasalized [ j ], that is, as a nasal glide. This vowel also exists in Guaraní.)
The term 'nasal stop' will often be abbreviated to just "nasal". However, there are also nasal fricatives, nasal flaps, nasal glides, and nasal vowels, as in French, Portuguese, Catalan (dialectal feature), Yoruba, Gbe, Polish, and Ljubljana Slovene. In the , nasal vowels are indicated by placing a tilde (~) over the vowel. : French "sang" .
A few languages use voiceless nasal consonants. Some of these are Icelandic, Burmese, Jalapa Mazatec, Kildin Sami, Welsh, and Central Alaskan Yup'ik.
Term (mathematics)
A term is a mathematical expression.
In elementary mathematics, a "term" is either a single number or variable, or the product of several numbers or variables. Terms are separated by a + or - sign in an overall expression. For example, in
3, 4"x", and 5"yzw" are three separate terms.
In the context of polynomials, "term" can mean a monomial with a coefficient. To combine like terms in a polynomial is to make it a linear combination of distinct monomials. For example,
A series is often represented as the sum of a sequence of terms.
In general mathematical use, however, "term" is not limited to additive expressions. Individual factors in an expression representing a product are multiplicative terms. Indeed, individual elements of any mathematical expression may be referred to as "terms".
In logic, a term is a collection of symbols used to represent a mathematical object (rather than a mathematical statement). A basic term is either a constant or a variable, while more complex terms can also be built using operators (such as the term formula_1). To refer to a term, variables such as formula_2 and formula_3 are often used.
In informal logic, a term can also refer to the subject or predicate of a statement.
Francisco Hernández de Córdoba (founder of Nicaragua)
Francisco Hernández de Córdoba (1475 ? - 1526) is usually reputed as the founder of Nicaragua, and in fact he founded two important Nicaraguan cities, Granada and León.
Francisco Hernández de Córdoba (Yucatán conquistador)
Francisco Hernández de Córdoba (died 1517) was a Spanish "conquistador", known to history mainly for the ill-fated expedition he led in 1517, in the course of which the first European accounts of the Yucatán Peninsula were compiled.
International Direct Dialing
International Direct Dialing (IDD) is an international telephone call dialed by the caller rather than going via an operator. Since late in the twentieth century, most international calls are direct dialed.
International calls are made by dialing the international call prefix for the country one is in, followed by the country calling code for the country one wishes to call, then the phone number within that country. When phone numbers are published for use abroad, they include the country calling code, but replace the international call prefix with "+" to signify that the caller should use the prefix appropriate for their country.
Direct-broadcast satellite
The Wii U ( ) is a video game console that was released by Nintendo on November 18, 2012, and is the successor of the Wii. The video game machine, or console, was first shown in Nintendo's press conference at the Electronic Entertainment Expo 2011 on June 7, 2011, and was released for sale on November 18, 2012 in North America; November 30, 2012 in Europe and Australia; and December 8, 2012 in Japan. The system has been described as a part of the eighth generation of video game consoles.
The Wii U is Nintendo's sixth home video game console and their first to use 1080p high-definition graphics. The Wii U has a new controller with a touchscreen, which allows the player to continue playing a game by showing the game even when the television is off. Wii games work on the Wii U, and Wii U games can be played with Wii controllers and extras, such as the Wii Remote, Wii MotionPlus, Wii Balance Board, and the Classic Controller. It also has a controller shaped like the Xbox 360 controller, for the hardcore gamers. Nintendo GameCube games and controllers will not work on the Wii U without the adapter used for Super Smash Bros for Wii U. However, it only works for that game. Like on the Wii and Nintendo 3DS, players can create Miis. The best-selling games for the system included "Mario Kart 8", "New Super Mario Bros. U", and "Nintendo Land". The Wii U received positive reviews but did not sell well at all. It has to deal with confusion if the game pad was a Wii accessory.
The main controller that was used by the Wii U was the Wii U Gamepad. The controller had a screen that was large. People can use the gamepad in many different ways. For example, people can play games on a television like a normal controller, or play on the gamepad without needing the television to be on.
FG 42
The FG 42 (German: "Fallschirmjägergewehr" 42 or "paratrooper rifle 42") was a battle rifle. It was made in Nazi Germany during World War II. The weapon was made for use by Fallschirmjäger airborne infantry in 1942. It was used in small amounts until the war ended.
The FG 42 had the power of a light machine gun. It was light and was no larger than the Kar 98k bolt-action rifle. The FG 42 is thought to be one of the most advanced weapons of World War II. It helped shape the modern assault rifle idea.
At the time of the Battle of Crete (Operation Mercury), German "Fallschirmjäger" had the same weapons as the regular army. When they jumped from aircraft, they only had pistols and hand grenades. Submachine guns, rifles and other heavier weapons were dropped in crates. The design of the German parachutes meant that it was not safe to carry heavier weapons like rifles on jumps. At Crete, Commonwealth defenders killed or injured many German soldiers. This is because the German paratroopers had to go and collect their weapons from containers. These could be all over the battlefield. This showed that the weapons the regular army used were not good for air operations.
In 1941, the German Air Force ("Luftwaffe"), asked for a selective fire weapon for the paratroopers. Senior Staff Air Secretary Ossenbach at the "Luftwaffe" Weapons Development Branch (at Tarnewitz near Lübeck) was asked to develop this new weapon. The Reich Air Ministry ("Reichsluftfahrtministerium" or RLM) wanted to develop an automatic rifle which would be fired from the shoulder. It would replace the bolt-action rifle, submachine gun and light machine gun for air assault. The weapon would also make logistics simpler and give more firepower to a normal paratrooper.
The RLM tried to start a formal development program using the "Heereswaffenamt" (the HWaA, or Army Ordnance Department). The HWaA was in charge of German small arms development. However, the HWaA and the "Luftwaffe" had different priorities. Also, there were some disagreements between the "Luftwaffe" and the Army (the HWaA said no to the program because they thought it was not realistic. They tried to give their G 41(W) semi-automatic rifle instead). This meant that the "Luftwaffe" had to develop the weapon by itself. The engineers who would develop the weapon were skilled at developing light automatic weapons (they managed to change the MG 15 aircraft machine gun so that it could also be used on the ground). However, the paratroopers had many casualties during Operation Mercury. Because of this, Hitler decided that air assaults were not important, and the plans for the weapon were cancelled. However, Hermann Göring, head of the "Luftwaffe", secretly ordered the program to continue.
The RLM went straight to German companies with its plans. The first plan was the LC-6. It was given out on 14 December 1941. It said that the weapon should not be longer than , that it should not be longer than the Kar 98k rifle, fire single shots from a closed bolt, fire fully automatically from an open bolt, take its bullets from a 10 or 20-round magazine and be able to fire rifle grenades. Although the 7.9mm "Kurz" cartridge used by the "Heer" (the main army) (developed for the MP 43 assault rifle) was in service, the "Luftwaffe" decided to use the 7.92 x 57mm Mauser rifle round. This was because it had long range. This caliber was also mentioned in the plans for the design.
Six companies were asked to design prototypes. These were: Gustloff-Werke, Mauser, Johannes Großfuß Metall- und Lackierwarenfabrik, C.G. Hänel, Rheinmetall-Borsig and Heinrich Krieghoff Waffenfabrik. Several contracts were given out, but only a few prototypes are known to have been given. Mauser gave a version of the MG 81. However, it was turned down because it was too heavy and got its bullets from a belt. There was one design, made by Louis Stange at Rheinmetall-Borsig, that was accepted. It was tested at a test station at Tarnewitz in mid-1942. This prototype was called Gerät" 450 ("device 450") or Ausführung" "A" ("type A"). It was supposed to be a sheet metal design. The type "A" was never made (except for some models). However, the basic design was kept for more development.
The basic parts of the LC-6 were accepted. A group of changes to the design came afterwards. The improved version of the LC-6 was called the "Ausführung" "B". This improvement changed the hand guard so that it gave better protection against heat and a better grip when it was wet.
These tests showed many problems. They were fixed by Stange in April 1942. This other improved version was called the LC-6/II. The prototype was then given many tests. These tests were set up by the HWA. The prototype was changed even more, and finally it became the LC-6/III prototype. This became the FG 42.
50 rifles were made in early 1943. Six of these were sent away to be tested more. These weapons had some serious faults. One rifle failed after firing only 2,100 rounds. Also, a soldier was injured when he tried to fire a rifle grenade.
Several other changes were made to the FG 42 before it was allowed to be made. The first Rheinmetall design used chrome-nickel steel a lot. It was used on many parts which were needed to make the weapon work. There was not much of this material around. When the "Luftwaffe" was allowed to make 3,000 rifles for some more testing, the weapon was changed and manganese steel was used instead of chrome-nickel steel. The Heinrich Krieghoff company was asked to make some FG 42s. This was because Rheinmetall was not large enough to make lots of FG 42s. The weapon was first used by commandos during "Operation Eiche" in 1943. "Operation Eiche" was the dangerous mission that some "Fallschirmjäger" went on. During this mission, they had to rescue Benito Mussolini. The "Fallschirmjäger" team was led by Otto Skorzeny.
The weapon kept being changed. Because its first design was changed many times and the "Luftwaffe" needed different things, many different types of FG 42 were made. Papers and books written after World War II usually say that there were three main versions of FG 42. However, the Germans never said that they were different models. The "Model I", "Model II" and "Model III" were never officially mentioned. German papers just call the weapon the "FG 42". It was always the latest version of FG 42 that was mentioned.
The BD 42/I is a semi-automatic copy of the early FG 42 rifle. The BD 42/II is a semi-automatic copy of the later FG 42. Both of these were made by HZA Kulmbach GmbH.
The FG 42 was a selective fire weapon. It was cooled by the air. The FG 42 also had its magazine at the side. It was quite easy to control if it was being fired on fully automatic mode.
The FG 42 got its bullets from a box-shaped magazine. This magazine could hold 10 or 20 rounds.
The FG 42 was semi-automatic when it was being fired from a closed bolt. There was not very much movement when the weapon was being fired. This meant that firing single shots was more accurate. When the weapon was being fired in automatic mode, it was fired from an open bolt. When automatic mode was on, the bolt stayed open to keep the weapon cool.
The FG 42 was supposed to give some useful firepower to Nazi Germany. However, only a small amount were made. When it was tested, the paratroopers quite liked it. However, the FG 42 did have some issues. The FG 42 had a 20, or sometimes 10, round magazine which was put into the left side of the rifle. It was quite usual for submachine guns to have magazines on the side, but the bigger magazine with the heavier cartridges of a rifle quite unbalanced. Also, the end of the FG 42 rose into the air quite quickly when it was being fired in automatic mode. This made accurate automatic fire difficult. It also meant that automatic fire was not very useful. The U.S. M14 rifle had problems similar to these.
The American M41 Johnson LMG has many things that are similar to the FG 42. Both of these had their magazines on the left side. They also fired from an open bolt in automatic mode and closed bolt in semi-automatic mode. Although there are some things that are similar, there is no evidence that the designers of one weapon copied the design of another.
The last known weapons that were based on the FG 42 are the Sturmgewehr 52 and M60 machine gun.
After around 2,000 FG 42s were made by Krieghoff, the manganese steel that many important parts were made from were moved away to be used for other things. This meant that the weapon had to be redesigned to use stamped steel. Soldiers using the FG 42 asked for many small changes to be made to the design. These changes can be seen on later FG 42s. The FG 42 also had a simple bayonet under the barrel. It was hidden by the bipod. In the later version of the FG 42, the bayonet was shortened. Before the update, it was . Afterwards, it changed to about .
Bioorganic chemistry
Bioorganic chemistry is a science that combines organic chemistry and biochemistry. Bioorganic chemistry expands organic chemistry towards biology. This differs from biochemistry, which studies biological processes using chemistry. When investigating enzymes and cofactors, bioorganic chemistry overlaps bioinorganic chemistry.
Biophysical organic chemistry is a term used when attempting to describe intimate details of molecular recognition by bioorganic chemistry.
Bioorganic chemistry is that branch of life science, which deals with the study of biological processes using chemical methods.
Carbocation
A carbocation is an ion with a positively-charged carbon atom. The charged carbon atom in a carbocation is a "sextet" (that is, it has only six electrons in its outer valence shell instead of eight valence electrons.) Carbon atoms with eight valence elections have the maximum stability (octet rule). Therefore, carbocations are often reactive, seeking to fill the octet of valence electrons as well as regain a neutral charge. Logic would say that carbocation have sp hybridization with an empty sp orbital giving positive charge. However, the reactivity of a carbocation more closely resembles sp hybridization with a trigonal planar molecular geometry.
A carbocation was previously often called a "carbonium ion" but chemists question the exact meaning. In present-day chemistry, a carbocation is any positively charged carbon atom. Two special types have been suggested: carbenium ions are trivalent and carbonium ions are pentavalent or hexavalent. University level textbooks only discuss carbocations as if they are carbenium ions, or discuss carbocations with a fleeting reference to the older phrase of carbonium ion or carbenium and carbonium ions. One textbook to this day stays with the older name of carbonium ion for carbenium ion and reserves the phrase "hypervalent carbenium ion" for CH.
In 1891, G. Merling reported that he added bromine to tropylidene (cycloheptatriene) and then heated the product to obtain a crystalline, water soluble material, . He did not suggest a structure for it; however Doering and Knox convincingly showed that it was tropylium (cycloheptatrienylium) bromide. This ion is predicted to be aromatic by the Hückel Rule.
In 1902, Norris and Kehrman independently discovered that colorless triphenylmethanol gave deep yellow solutions in concentrated sulfuric acid. Triphenylmethyl chloride similarly formed orange complexes with aluminium and tin chlorides. In 1902, Adolf von Baeyer recognized the salt-like character of the compounds formed.
He called the relationship between color and salt formation halochromy of which malachite green is a prime example.
Carbocations are reactive intermediates in many organic reactions. This idea, first proposed by Julius Stieglitz in 1899 was further developed by Hans Meerwein in his 1922 study of the Wagner-Meerwein rearrangement. Carbocations were also found to be involved in the S1 reaction, the E1 reaction, and in rearrangement reactions such as the Whitmore 1,2 shift. The chemical establishment was reluctant to accept the notion of a carbocation and for a long time the "Journal of the American Chemical Society" refused articles that mentioned them.
The first NMR spectrum of a stable carbocation in solution was published by Doering et al. in 1958. It was the heptamethylbenzenonium ion, made by treating hexamethylbenzene with methyl chloride and aluminium chloride. The stable 7-norbornadienyl cation was prepared by Story et al. in 1960 by reacting norbornadienyl chloride with silver tetrafluoroborate in sulfur dioxide at −80 °C. The NMR spectrum established that it was non-classically bridged (the first stable non-classical ion observed).
In 1962, Olah directly observed the tert-butyl carbocation by nuclear magnetic resonance as a stable species on dissolving tert-butyl fluoride in magic acid. The NMR of the norbornyl cation was first reported by Schleyer et al. and it was shown to undergo proton-scrambling over a barrier by Saunders et al.
In organic chemistry, a carbocation is often the target of nucleophilic attack by nucleophiles like hydroxyl (OH) ions or halogen ions.
Carbocations are classified as primary, secondary, or tertiary depending on the number of carbon atoms bonded to the ionized carbon. Primary carbocations have one or zero carbons attached to the ionized carbon, secondary carbocations have two carbons attached to the ionized carbon, and tertiary carbocations have three carbons attached to the ionized carbon.
Stability of the carbocation increases with the number of alkyl groups bonded to the charge-bearing carbon. Tertiary carbocations are more stable (and form more readily) than secondary carbocations; primary carbocations are highly unstable because, while ionized higher-order carbons are stabilized by hyperconjugation, unsubstituted (primary) carbons are not. Therefore, reactions such as the S1 reaction and the E1 elimination reaction normally do not occur if a primary carbocation would be formed. An exception to this occurs when there is a carbon-carbon double bond next to the ionized carbon. Such cations as "allyl" cation CH=CH–CH and "benzyl" cation CH–CH are more stable than most other carbocations. Molecules which can form allyl or benzyl carbocations are especially reactive.
Carbocations undergo rearrangement reactions from less stable structures to equally stable or more stable ones with rate constants in excess of 10/sec. This fact complicates synthetic pathways to many compounds. For example, when 3-pentanol is heated with aqueous HCl, the initially formed 3-pentyl carbocation rearranges to a statistical mixture of the 3-pentyl and 2-pentyl. These cations react with chloride ion to produce about 1/3 3-chloropentane and 2/3 2-chloropentane.
Some carbocations such as the norbornyl cation exhibit more or less symmetrical three centre bonding. Cations of this sort have been referred to as non-classical ions. The energy difference between "classical" carbocations and "non-classical" isomers is often very small, and there is generally little, if any activation energy involved in the transition between "classical" and "non-classical" structures. The "non-classical" form of the 2-butyl carbocation is essentially 2-butene with a proton directly above the centre of what would be the carbon-carbon double bond. "Non-classical" carbocations were once the subject of great controversy. One of George Olah's greatest contributions to chemistry was resolving this controversy.
Cyclopropylcarbinyl cations can be studied by NMR:
In the NMR spectrum of a dimethyl derivative, two nonequivalent signals are found for the two methyl groups indicating that the molecular conformation of this cation not perpendicular (as in A) but is bisected (as in B) with the empty p-orbital and the cyclopropyl ring system in the same plane:
In terms of bent bond theory, this preference is explained by assuming favorable orbital overlap between the filled cyclopropane bent bonds and the empty p-orbital.
Isodesmic reaction
An isodesmic reaction is a chemical reaction where the type of chemical bonds broken in the reactant are the same as the type of bonds formed in the reaction product. This type of reaction is often used as a hypothetical reaction in thermochemistry.
An example of an isodesmic reaction is
Equation 1 describes the deprotonation of a methyl halide by a methyl anion. The energy change associated with this exothermic reaction can be calculated using a computer. The energy change increases going from fluorine to chlorine to bromine and iodine. This shows that the CHI anion is the most stable and least basic of all the halides. Each of these reactions are isodesmic. The energy change in each example also depends on the difference in bond energy of the C-X bond in the base and conjugate acid. In other cases, the difference may be due to steric strain (the blocking of atoms by other atoms). The steric strain is small in fluorine (which is a small diameter atom) but large in iodine (in favor of the anion). So, the energy change grows between each example halide despite the fact that C-F bonds are stronger than C-I bonds.
The related term homodesmotic reaction also takes into account orbital hybridization. Homodesmotic reactions also have the same number of carbon to hydrogen (C-H) bonds. An example of a homodesmotic reaction is:
A spit is a depositional landform found off coasts. Spits connect to the beach, and extend into the sea. A spit forms because the sand on the beach is moved by the waves along the shore, and the sand collects at the end to form a spit. The process of the waves moving the sand along the shore is known as longshore drift.
The sawfish are a family of rays which have a long body, like a shark. One feature that separates a sawfish from other rays is its long, saw-like snout. On either side of this "rostrum" are little teeth like a saw.
Sawfish have a mouth, nostrils, and gill slits under their body, just like a ray. Also, their pectoral fins are enlarged, like those of a ray. Also like rays, when they settle on the bottom, they take in water through two spiracles just behing the eyes. This gets water to the gills without sand.
Several species can grow to about .
The sawfish's most distinctive feature is the saw-like rostrum. The rostrum is covered with motion- and electro-sensitive pores. These allow sawfish to detect movement and even heartbeats of prey hiding under the ocean floor. The rostrum serves as a digging tool to unearth buried crustaceans.
If a suitable prey swims by, the normally lethargic sawfish springs from the bottom and slashes at it with its saw. This generally stuns or injures the prey sufficiently for the sawfish to devour it. Sawfish also defend themselves with their rostrum, against predators such as sharks and intruding divers. The 'teeth' protruding from the rostrum are not real teeth, but modified tooth-like structures called "denticles".
Eagle ray
Eagle rays are cartilaginous fish in the ray family Myliobatidae. They are mostly large species living in the open ocean rather than on the sea bottom.
Eagle rays feed on molluscs and crustaceans, crushing their shells with their flattened teeth, while devil rays and manta rays filter plankton from the water.
They are excellent swimmers and are able to breach the water up to several metres above the surface. Compared with other rays, they have long tails, and well-defined diamond-shaped bodies. They are ovoviviparous, giving birth to up to six young at a time. They range from to in length.
The tail looks like a whip and may be as long as the body. It is armed with a sting. Eagle rays live close to the coast in depths of 1 to 30 metres and in exceptional cases they are found as deep as 300 m. The eagle ray is commonly seen cruising along sandy beaches in very shallow waters.
In Nelson's "Fishes of the World", the eagle rays are a subfamily, and are joined by the manta rays and the eagle rays. As Nelson sees it, there are seven genera in the family, in three subfamilies. In our classification, the three groups are families in the suborder Myliobatoidei.
Glasgow Prestwick Airport
Glasgow Prestwick Airport is the second airport serving Glasgow. It also serves the Greater Glasgow area. It is northeast of the town of Prestwick in South Ayrshire. It is 32 miles from the city centre of Glasgow.
Prestwick is Scotland's largest airport by size. However, Edinburgh Airport, Glasgow International and Aberdeen Airport all handle more passengers. The year with the most passengers passing through Prestwick was 2007. Since 2007, a lot less passengers pass through Prestwick. 1.3 million passengers passed through the airport in 2011. This was 22% reduction from 2010.
Douglas Fowler McIntyre and the Duke of Hamilton owned the airport at first. These people were the first to fly a plane to the top of Mount Everest in 1933. During and after World War II it was a Royal Air Force base. In 1952 it was made a United States Air Force base.
The airport was made bigger in the early 1960s: the runway was made longer and a new terminal building was made. The new, bigger airport opened in 1964. Today, Glasgow Prestwick is mostly used by Ryanair.
On 8 March 2012, Infratil, the company which owns Prestwick, said that they had placed the airport up for sale. The Chief Executive Marco Bogoievski said that he does not regret selling the airport.
The Royal Navy Fleet Air Arm uses part of the airport. It has 3 Sea King helicopters there for search and rescue. They cover Ben Nevis, the Lakes, Northern Ireland and 200 NM (370 km; 230 mi) past the Irish coast. This force is often called 'HMS Gannet'. 15 officers, 11 ratings, 28 civil servants and 50 civilian staff work at the base.
Shamarpa
Shamarpa or more formally Kunzig Shamar Rinpoche is Tibetan Buddhis teacher. Together with Karmapa he is the second lineage holder of the Karma Kagyu school of Tibetan Buddhism. Shamarpa is regarded as manifestation of Amitabha Buddha. He also is the second lama who consciously incarnates in subsequent order of Buddhist teachers.
The first Shamar Rinpoche Khedrup Drakpa Senge (1284–1349) was the principal disciple of the 3rd Karmapa Rangjung Dorje.
The present (14th) Shamarpa is Mipham Chokyi Lodro, born in Derge, Tibet in 1952. At age four he was recognized by his uncle the 16th Karmapa.
Nāropā (956–1041) was an Indian Buddhist teacher. He was the disciple of Tilopa and also brother and pupil of Niguma. Naropa was the main teacher of Marpa, the founder of the Kagyu school of Tibetan Buddhism.
Naropa was born a high status Brahmin and from an early age showed strong, highly intelligent mind. At the age of 28 Naropa entered the famous Buddhist University at Nalanda where he studied both Sutra and Tantra. He had the reputation of a great scholar and debater. Later Naropa became studend of Tilopa and spent twelve years with him. While studying and meditating with his teacher Naropa met and overcame twelve minor and twelve major hardships. Eventually he reached full realization and become teacher of Marpa.
Iodine deficiency
Iodine deficiency is when there is not enough iodine in the body. Iodine is an essential trace element. The thyroid hormones thyroxine and triiodotyronine have iodine. In areas where marine food is not eaten, there is low iodine in the diet. This causes iodine deficiency which gives rise to
goiter (so-called endemic goiter), as well as cretinism, which results in developmental delays and other health problems.
"The Lancet" has said, "According to WHO, in 2007, nearly 2 billion individuals had insufficient iodine intake, a third being of school age. ... Thus iodine deficiency, as the single greatest preventable cause of mental retardation, is an important public-health problem." Iodine deficiency causes diseases of the oral and salivary glands.
In these areas,small amounts of iodine to table salt in form of sodium iodide, potassium iodide, and/or potassium iodate is added. This helps preventing iodine deficiency. This product is known as "iodized salt". Iodine compounds have also been added to other foods. This includes flour, water and milk in areas of deficiency. Seafood is also a well known source of iodine. Thus, iodine deficiency is more common in mountainous regions of the world where food is grown in soil poor in iodine.
John Haymes Newton
William Griffiths (VC)
Trachea
The trachea, or windpipe, is the bony tube that connects the nose and mouth to the lungs, and is an important part of the vertebrate respiratory system. In mammals, the trachea begins at the lower part of the larynx and continues to the lungs, where it branches into the right and left bronchi. Inflammation of the trachea can lead to other conditions, such as tracheitis, which is the inflammation of the linings of the trachea.
The invertebrate trachea refers to the open respiratory system of terrestrial arthropods. It consists of spiracles, tracheae, and tracheoles that take metabolic gases to and from tissues. The distribution of spiracles varies, but in general each segment of the body has only one pair of spiracles, each of which connects to an atrium and has a relatively large tracheal tube behind it.
The smallest tubes, tracheoles, penetrate cells and diffuse water, oxygen, and carbon dioxide. Gas may be moved actively or by passive diffusion. Unlike vertebrates, insects do not generally carry oxygen in their haemolymph.
This is one of the factors that may limit their size.
A tracheal tube may contain ridge-like circumferential rings of taenidia in various geometries such as loops or helices. In the head, thorax, or abdomen, tracheae may also be connected to air sacs. Many insects, such as grasshoppers and bees, which actively pump the air sacs in their abdomen, are able to control the flow of air through their body. In some aquatic insects, the tracheae exchange gas through the body wall directly, in the form of a gill, or function as normal, via a plastron. Despite being internal, the tracheae of arthropods are shed during moulting (ecdysis).
Pete Smith (baseball, born 1966)
Peter John Smith (born February 27, 1966 in Abington, Massachusetts) is a former Major League Baseball starting pitcher. He was drafted by the Philadelphia Phillies in the 1st round (21st overall pick) in the amateur draft of 1984. Smith was signed on June 14, 1984 to play Minor League Baseball in the Philadelphia Phillies organization. He batted and threw right-handed during his baseball career.
The Philadelphia Phillies traded Smith to the Atlanta Braves, along with Ozzie Virgil, Jr., for Steve Bedrosian and Milt Thompson. Smith made his major league debut on September 8, 1987 with the Atlanta Braves at age 21. In 1988, Smith pitched 3 shutouts, the season after his rookie year. The Atlanta Braves hoped Smith would turn into an ace pitcher as John Smoltz and Tom Glavine were becoming. But in 1989, Smith's earned run average (ERA) was at 4.75 at the end of the season, higher than his ERA in 1988 when it was at 3.69. He played the 1987-1993 seasons with the Atlanta Braves before being traded to the New York Mets for Dave Gallagher. With the New York Mets, Smith only played the 1994 season before being granted free agency on October 25 of that year. On December 1, 1994, Smith was signed as a free agent with the Cincinnati Reds. He played with the Cincinnati Reds for only half of the 1995 season before being traded to the Florida Marlins on July 1, 1995 as a free agent. On December 23, 1995, Smith signed as a free agent with the San Diego Padres playing one season with them.
On June 9, 1998, Smith was traded to the Baltimore Orioles organization for minor leaguer, Eric Estes. He played his final game on September 24, 1998. He earned a career ERA of 4.55, striking out 640 batters. Smith also pitched 4 shutouts throughout his major league career.
Pete L. Smith
Trachea (disambiguation)
The trachea is a tube in animals that connects the mouth to the lungs.
Trachea might also refer to:
Urban Dictionary is a website which is a dictionary of slang words. The website was created in 1999 by California Polytechnic State University freshman, Aaron Peckham. The website was listed as #29 in Time's list of 50 best websites of 2008. The website has been featured on Tosh.0's "words of the week". As of January 2011, Urban Dictionary has a alexa rating of 688.
Electric ray
The electric rays are a group of rays, flattened cartilaginous fish with enlarged pectoral fins. They are the order Torpediniformes.
They can produce an electric discharge, ranging from as little as 8 volts up to 220 volts depending on species. There are 69 species in four subfamilies.
These rays have battery-like electric organs on both sides of their heads, which can make a powerful electric shock. They use this shock to stun their prey and for their own self defense.
Electric rays are found from shallow coastal waters down to at least depth. They are sluggish and slow moving, propelling themselves along with their tails, rather than using their disc-shaped bodies, as other rays do. They feed on invertebrates and small fish. They lie in wait for prey below the sand or other substrate, using their electricity to stun and capture it.
The electric rays are regarded as monophyletic, though in detail the group has been classified in several ways. This is one way the order can be classified.
The word torpedo comes from a genus of electric rays in the sub-family Torpedininae, namely "Torpedo", which in turn comes from the Latin "torpere" (to be stiff or numb).