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Chemical synapse

Chemical synapses are biological junctions through which neurons' signals can be sent to each other and to non-neuronal cells such as those in muscles or glands. Chemical synapses allow neurons to form circuits within the central nervous system, they thought. They allow the nervous system to control other systems of the body. At a chemical synapse, one neuron releases neurotransmitter molecules into a small space, adjacent to another neuron; the neurotransmitters are contained within small sacs called synaptic vesicles, are released into the synaptic cleft by exocytosis. These molecules bind to neurotransmitter receptors on the postsynaptic cell; the neurotransmitters are cleared from the synapse through one of several potential mechanisms including enzymatic degradation or re-uptake by specific transporters either on the presynaptic cell or on some other neuroglia to terminate the action of the neurotransmitter. The adult human brain is estimated to contain from 1014 to 5 × 1014 synapses; every cubic millimeter of cerebral cortex contains a billion of them.

The number of synapses in the human cerebral cortex has separately been estimated at 0.15 quadrillion The word "synapse" comes from "synaptein", which Sir Charles Scott Sherrington and colleagues coined from the Greek "syn-" and "haptein". Chemical synapses are not the only type of biological synapse: electrical and immunological synapses exist. Without a qualifier, however, "synapse" refers to chemical synapse. Synapses are functional connections between neurons and other types of cells. A typical neuron gives rise to several thousand synapses, although there are some types that make far fewer. Most synapses connect axons to dendrites, but there are other types of connections, including axon-to-cell-body, axon-to-axon, dendrite-to-dendrite. Synapses are too small to be recognizable using a light microscope except as points where the membranes of two cells appear to touch, but their cellular elements can be visualized using an electron microscope. Chemical synapses pass information directionally from a presynaptic cell to a postsynaptic cell and are therefore asymmetric in structure and function.

The presynaptic axon terminal, or synaptic bouton, is a specialized area within the axon of the presynaptic cell that contains neurotransmitters enclosed in small membrane-bound spheres called synaptic vesicles. Synaptic vesicles are docked at the presynaptic plasma membrane at regions called active zones. Opposite is a region of the postsynaptic cell containing neurotransmitter receptors. Behind the postsynaptic membrane is an elaborate complex of interlinked proteins called the postsynaptic density. Proteins in the PSD are involved in anchoring and trafficking neurotransmitter receptors and modulating the activity of these receptors; the receptors and PSDs are found in specialized protrusions from the main dendritic shaft called dendritic spines. Synapses may be described as asymmetric; when examined under an electron microscope, asymmetric synapses are characterized by rounded vesicles in the presynaptic cell, a prominent postsynaptic density. Asymmetric synapses are excitatory. Symmetric synapses in contrast have flattened or elongated vesicles, do not contain a prominent postsynaptic density.

Symmetric synapses are inhibitory. The synaptic cleft —also called synaptic gap— is a gap between the pre- and postsynaptic cells, about 20 nm wide; the small volume of the cleft allows neurotransmitter concentration to be raised and lowered rapidly. An autapse is a chemical synapse formed. Here is a summary of the sequence of events that take place in synaptic transmission from a presynaptic neuron to a postsynaptic cell; each step is explained in more detail below. Note that with the exception of the final step, the entire process may run only a few hundred microseconds, in the fastest synapses; the process begins with a wave of electrochemical excitation called an action potential traveling along the membrane of the presynaptic cell, until it reaches the synapse. The electrical depolarization of the membrane at the synapse causes channels to open that are permeable to calcium ions. Calcium ions flow through the presynaptic membrane increasing the calcium concentration in the interior; the high calcium concentration activates a set of calcium-sensitive proteins attached to vesicles that contain a neurotransmitter chemical.

These proteins change shape, causing the membranes of some "docked" vesicles to fuse with the membrane of the presynaptic cell, thereby opening the vesicles and dumping their neurotransmitter contents into the synaptic cleft, the narrow space between the membranes of the pre- and postsynaptic cells. The neurotransmitter diffuses within the cleft; some of it escapes, but some of it binds to chemical receptor molecules located on the membrane of the postsynaptic cell. The binding of neurotransmitter causes the receptor molecule to be activated in some way. Several types of activation are possible. In any case, this is the key step by which the synaptic process affects the behavior of the postsynaptic cell. Due to thermal vibration, the motion of atoms, vibrating about their equilibrium positions in a crystalline solid, ne

Rokhlin's theorem

In 4-dimensional topology, a branch of mathematics, Rokhlin's theorem states that if a smooth, closed 4-manifold M has a spin structure the signature of its intersection form, a quadratic form on the second cohomology group H 2, is divisible by 16. The theorem is named for Vladimir Rokhlin, who proved it in 1952; the intersection form on M Q M: H 2 × H 2 → Z is unimodular on Z by Poincaré duality, the vanishing of w 2 implies that the intersection form is even. By a theorem of Cahit Arf, any unimodular lattice has signature divisible by 8, so Rokhlin's theorem forces one extra factor of 2 to divide the signature. A K3 surface is compact, 4 dimensional, w 2 vanishes, the signature is −16, so 16 is the best possible number in Rokhlin's theorem. A complex surface in C P 3 of degree d is spin if and only, it has signature d / 3. The case d = 4 gives back the last example of a K3 surface. Michael Freedman's E8 manifold is a connected compact topological manifold with vanishing w 2 and intersection form E 8 of signature 8.

Rokhlin's theorem implies. This manifold shows that Rokhlin's theorem fails for the set of topological manifolds. If the manifold M is connected the vanishing of w 2 is equivalent to the intersection form being even; this is not true in general: an Enriques surface is a compact smooth 4 manifold and has intersection form II1,9 of signature −8, but the class w 2 does not vanish and is represented by a torsion element in the second cohomology group. Rokhlin's theorem can be deduced from the fact that the third stable homotopy group of spheres π 3 S is cyclic of order 24, it can be deduced from the Atiyah–Singer index theorem. See  genus and Rochlin's theorem. Robion Kirby gives a geometric proof. Since Rokhlin's theorem states that the signature of a spin smooth manifold is divisible by 16, the definition of the Rohkhlin invariant is deduced as follows: For 3-manifold N and a spin structure s on N, the Rokhlin invariant μ in Z / 16 Z is defined to be the signature of any smooth compact spin 4-manifold with spin boundary.

If N is a spin 3-manifold it bounds a spin 4-manifold M. The signature of M is divisible by 8, an easy application of Rokhlin's theorem shows that its value mod 16 depends only on N and not on the choice of M. Homology 3-spheres have a unique spin structure so we can define the Rokhlin invariant of a homology 3-sphere to be the element sign ⁡ / 8 of Z / 2 Z, where M any spin 4-manifold bounding the homology sphere. For example, the Poincaré homology sphere bounds a spin 4-manifold with intersection form E 8, so its Rokhlin invariant is 1; this result has some elementary consequences: the Poincaré homology sphere does not admit a smooth embedding in S 4, nor does it bound a Mazur manifold. More if N is a spin 3-manifold the signature of any spin 4-manifold M with boundary N is well defined mod 16, is called the Rokhlin invariant of N. On a topological 3-manifold N, the generalized Rokhlin invariant refers to the function whose domain is the spin structures on N, which evaluates to the Rokhlin invariant of the pair where s is a spin structure on N.

The Rokhlin invariant of M is equal to half the Casson invariant mod 2. The Casson invariant is viewed as the Z-valued lift of the Rokhlin invariant of integral ho

Kenneth McKellar (singer)

Kenneth McKellar was a Scottish tenor. McKellar studied forestry at the University of Aberdeen, after graduation working for the Scottish Forestry Commission, he trained at the Royal College of Music as an opera singer. He did not enjoy his time with the Carl Rosa Opera Company and left them to pursue a career singing traditional Scottish songs and other works. From 1959 to 1977 he toured the United States and Canada with other Scottish entertainers such as Helen McArthur appearing in small local venues. From 1957 he starred each year in innovative pantomimes by Howard & Wyndham Ltd notably at their Alhambra Theatre Glasgow. In 1958/59 he played Jacob Bray in a successful revival of'Old Chelsea' by Richard Tauber, along with Vanessa Lee and Peter Graves, which opened in Glasgow and toured. For a decade from 1960 he starred as Jamie in the new pantomimes devised around him, starting with A Wish For Jamie, followed by A Love For Jamie, which ran at the Alhambra in each of five years, accompanied by Rikki Fulton, moved after to Edinburgh and Newcastle.

He described these years as the most fulfilling of his stage life outside his international recording career. McKellar toured New Zealand in 1964. On many occasions in the 1960s and 1970s he appeared on the BBC Television Hogmanay celebration programme, alongside Jimmy Shand, Andy Stewart and Moira Anderson, he made numerous appearances on the popular White Heather Club television series, hosted by Andy Stewart. His last Hogmanay Show appearance was on STV in 1991. In 1965, the BBC selected McKellar to represent the UK in the Eurovision Song Contest in Luxembourg, he sang five titles from. According to author and historian John Kennedy O'Connor's The Eurovision Song Contest – The Official History, the Scottish tenor – who had changed into a kilt at the last moment – drew gasps from the audience when he appeared on stage; the song was placed ninth of the eighteen entries, making it the least successful UK placing in the contest until 1978. McKellar received scores from only two countries; the Irish jury gave the UK song top marks, one of only two occasions the Irish have done so in Eurovision history."A Man Without Love" peaked at #30 in the UK Singles Chart in March 1966.

His albums The World of Kenneth McKellar, Ecco Di Napoli, had a total of ten weeks presence in the UK Albums Chart. He recorded an album in Afrikaans, entitled Kuier By Ons, released just before his tour of South Africa in October 1970. On 31 December 1973, the first Scottish commercial radio station Radio Clyde began broadcasting to Glasgow; the first record they played was "Song of the Clyde". The same recording featured over the opening titles of the 1963 film Billy Liar. McKellar lived in Lenzie, Glasgow in the house called "Machrie Mhor". Outside music, McKellar wrote a sketch, performed by the Monty Python team at The Secret Policeman's Ball; this was the only time. McKellar made the majority of his recordings on the Decca Records label, he recorded several classical works, including Handel's Messiah alongside Joan Sutherland in a performance conducted by Sir Adrian Boult. After he left Decca in the 1970s he recorded from 1983–1996 for Lismor records, recording several albums for them before retiring in the late 1990s.

McKellar recorded the musical Kismet with Robert Merrill. He was notable for his recordings of Gaelic songs in translation such as the Songs of the Hebrides arrangements by Marjory Kennedy-Fraser. McKellar died of pancreatic cancer, at the age of 82, at his daughter's home near Lake Tahoe in the United States, on 9 April 2010, his funeral was in Paisley. Songs of Ireland 1964 TW 91321 Kenneth McKellar on IMDb Kenneth McKellar – Lost in the white heather Kenneth McKellar dies Kenneth McKellar – Daily Telegraph obituary

North Acomita Village, New Mexico

North Acomita Village is a census-designated place in Cibola County, New Mexico, United States. The population was 303 at the 2010 census. North Acomita Village is located in northeastern Cibola County at 35°4′4″N 107°33′55″W, it occupies the northeastern corner of the Acoma Pueblo land and is situated on the north side of the Rio San Jose and south of Interstate 40. Two I-40 exits serve the North Acomita area. South Acomita Village is directly across the Rio San Jose. According to the United States Census Bureau, the CDP has a total area of 2.9 square miles, all of it land. As of the census of 2000, there were 288 people, 90 households, 63 families residing in the CDP; the population density was 103.3 people per square mile. There were 104 housing units at an average density of 37.3 per square mile. The racial makeup of the CDP was 3.47% White, 95.83% Native American, 0.69% from two or more races. Hispanic or Latino of any race were 3.12% of the population. There were 90 households out of which 32.2% had children under the age of 18 living with them, 41.1% were married couples living together, 20.0% had a female householder with no husband present, 30.0% were non-families.

24.4% of all households were made up of individuals and 7.8% had someone living alone, 65 years of age or older. The average household size was 3.20 and the average family size was 3.87. In the CDP, the population was spread out with 29.5% under the age of 18, 10.1% from 18 to 24, 26.0% from 25 to 44, 24.7% from 45 to 64, 9.7% who were 65 years of age or older. The median age was 34 years. For every 100 females, there were 95.9 males. For every 100 females age 18 and over, there were 76.5 males. The median income for a household in the CDP was $24,375, the median income for a family was $25,000. Males had a median income of $26,250 versus $20,000 for females; the per capita income for the CDP was $10,569. About 36.2% of families and 33.2% of the population were below the poverty line, including 40.2% of those under the age of eighteen and 50.0% of those sixty five or over. All public schools in the county are operated by Grants/Cibola County Schools. Acoma Pueblo Acoma Indian Reservation

Triton (comics)

Triton is a fictional character, an Inhuman appearing in American comic books published by Marvel Comics. Triton made his live action debut in Marvel Cinematic Universe with the television series Inhumans, portrayed by Mike Moh, he first appeared in Fantastic Four #45, was created by Stan Lee and Jack Kirby. Triton is member of the Inhumans' Royal Family, son of Mander and Azur, brother to Karnak, cousin to Gorgon, Black Bolt, Maximus and Crystal. Triton was born on the city-state island of Attilan and was exposed to the Terrigen Mist as an infant; the mists altered his body, turning his skin green and giving him the ability to breathe underwater, as well as surviving the cold temperatures and incredible pressures of the deep. An unfortunate side effect was the loss of the ability to survive in a non-aquatic environment; as a result, he lived in a designed area of Attilan, requiring a special breathing apparatus to leave the water. The apparatus, cumbersome at first, was reduced in size by fellow Inhuman, Maximus the Mad.

Triton's mutation after Terrigenesis was so severe that his parents disallowed his brother Karnak from going through it. Triton first encountered the Fantastic Four. During an accidental encounter, he tells his fellow Inhumans he recognizes the Hulk from Reed Richard's micro-film files. Triton acquires an artificial life support system, he first left the Great Refuge with the other members of the Royal Family, acting as a scout for them. He is freed from the "negative zone" barrier, along with the rest of the Inhumans, he aids the Fantastic Four in battle against Blastaar. Triton met the Sub-Mariner, battled Plantman's Leviathan, he aided the Inhuman Royal Family in defeating Maximus's attempt to overthrow the Great Refuge. He singlehandedly captured Maximus, battled the Mandarin alongside the Royal Family, he traveled to New York to warn the Avengers of the Inhumans' involvement in the Kree-Skrull War. Triton battled the Kree Kaproids, he traveled to New York City with the Royal Family seeking aid for the earthquake threatened Attilan, battled Shatterstar.

He was imprisoned by Maximus, aided the Royal Family in the defeat of Maximus and his evil Inhumans. He left Earth with the Inhuman Royal Family to prevent the Kree subjugation of the Inhumans, battled various aliens, he returned to Earth and battled the Kree agent, the Pursuer. He battled the Hulk alongside the Royal Family. Triton participated in the Inhuman exodus, he grappled with the Avengers under Maximus's mind control. He accompanied Medusa to Earth when she fled Attilan to avoid compulsory abortion by order of the Genetic Council. Triton battled mutated aquatic life caused by toxic waste. Triton has maintained a friendship with Namor the Sub-Mariner and has been involved in stories with Marvel's other ocean-dwelling characters, he had pivotal roles in major crossover stories such as the Kree -- Atlantis Attacks. Triton expresses discontent to Black Panther and Storm when they visit Attilan's current moon location, he reveals that several underground chambers have been flooded for his benefit, but it is not satisfactory.

During the Secret Invasion storyline, the Inhuman royal family forges an alliance with the Kree to recover Black Bolt from the Skrulls' clutches. Together, they discover a weakness in the Skrull's defense and split up to recover the resources to exploit it. Triton is sent to the all-water planet Pelagia where he encounters a race of mermen-like beings that resemble him in appearance, he develops feelings for Dascylla. Although outnumbered by the hostile Pelagians, Triton manages to overcome them and find what he seeks, his breathing harness is upgraded by the Kree allowing him to operate in the vacuum of space thus enabling him to physically attack the Skrulls' ship during the rescue. During Civil War II, Triton grows discontent with Medusa's dovishness to Tony Stark's aggression against New Attilan, he enlists the help of Maximus to provoke Stark against Medusa to force her to attack. Maximus convinces Lash to attack one of Stark's factories. Captain Marvel and the Avengers attack Medusa. To Triton's shock, Maximus lowers Attilan's defenses, allowing Stark to enter.

Medusa surrenders. SHIELD takes him to the Triskelion prison. During Inhumans vs. X-Men, Maximus free Triton from the Triskelion with the promise of finding a way to recreate Terrigen Crystals. Triton and the Unspoken travel around the world gathering ingredients. Maximus instead creates a giant robot with a Terrigen sword to kill the X-Men, but The Unspoken attacked and absorbed the Terrigen sword. Triton vowed to kill Maximus if he didn't follow through with the plan, but doesn't since Maximus is the only one who knows the formula. Karnak and Lockjaw go to find Triton, but Maximus controls him and makes him attack his brother, so Karnak incapacitates him, he is allowed back into the Royal Family. In Death of the Inhumans, the Kree have murdered thousands of Inhumans; this causes Black Bolt requested a meeting with the four Queens of the Inhumans tribes to respond to this threat. When Triton tries to learn what transpired, he discovers that Black Bolt has been wired with an explosive which isactivated when Triton touches him.

Triton is killed in the explosion, although most of the Royal Family is saved by Lockjaw's teleportation ability. It is revealed that Triton is in some kind of stasis tank alongside Naja and other unnamed Inhumans as they are being experimented

A Patriotic Offering

A Patriotic Offering is the first episode of the fourth series of the period drama Upstairs, Downstairs. It first aired on 14 September 1974 on ITV. Regular castAngela Baddeley - Mrs Bridges Gordon Jackson - Hudson Meg Wynn Owen - Hazel Bellamy David Langton - Richard Bellamy Christopher Beeny - Edward Jacqueline Tong - Daisy Jenny Tomasin - RubyGuest castMrs. Hollins grandfather Monsieur Chargon daughter Madame Chargon daughter in law Madame Huguot granddaughter Celestine grandson Jean-Paul Lady Berkhamstead Monsieur Chargon comes to Eaton Place with his daughter and his daughter in law, they are refugees of the War in Belgium and they tell the story of death and terror. Monsieur Chargon is the father of Madame Chargon and the grandfather of the little boy Jean-Paul and the little girl Celestine, his wife was never found. His son and grandson were killed in the fighting at the hands of the invading Germans and his little granddaughter died. Madame Chargon is the daughter of the old man Monsieur Chargon.

Her husband was executed by the Germans. She came together with her little daughter Celestine. Madame Huguot is the wife of the old man's son, she lost her husband and son in the fighting and her little daughter in her arms was killed in bombing. Only the daughter's doll remained. "A Patriotic Offering" on IMDb