Oxford University Press
Oxford University Press is the largest university press in the world, the second oldest after Cambridge University Press. It is a department of the University of Oxford and is governed by a group of 15 academics appointed by the vice-chancellor known as the delegates of the press, they are headed by the secretary to the delegates, who serves as OUP's chief executive and as its major representative on other university bodies. Oxford University has used a similar system to oversee OUP since the 17th century; the Press is located on opposite Somerville College, in the suburb Jericho. The Oxford University Press Museum is located on Oxford. Visits are led by a member of the archive staff. Displays include a 19th-century printing press, the OUP buildings, the printing and history of the Oxford Almanack, Alice in Wonderland and the Oxford English Dictionary; the university became involved in the print trade around 1480, grew into a major printer of Bibles, prayer books, scholarly works. OUP took on the project that became the Oxford English Dictionary in the late 19th century, expanded to meet the ever-rising costs of the work.
As a result, the last hundred years has seen Oxford publish children's books, school text books, journals, the World's Classics series, a range of English language teaching texts. Moves into international markets led to OUP opening its own offices outside the United Kingdom, beginning with New York City in 1896. With the advent of computer technology and harsh trading conditions, the Press's printing house at Oxford was closed in 1989, its former paper mill at Wolvercote was demolished in 2004. By contracting out its printing and binding operations, the modern OUP publishes some 6,000 new titles around the world each year; the first printer associated with Oxford University was Theoderic Rood. A business associate of William Caxton, Rood seems to have brought his own wooden printing press to Oxford from Cologne as a speculative venture, to have worked in the city between around 1480 and 1483; the first book printed in Oxford, in 1478, an edition of Rufinus's Expositio in symbolum apostolorum, was printed by another, printer.
Famously, this was mis-dated in Roman numerals as "1468", thus pre-dating Caxton. Rood's printing included John Ankywyll's Compendium totius grammaticae, which set new standards for teaching of Latin grammar. After Rood, printing connected with the university remained sporadic for over half a century. Records or surviving work are few, Oxford did not put its printing on a firm footing until the 1580s. In response to constraints on printing outside London imposed by the Crown and the Stationers' Company, Oxford petitioned Elizabeth I of England for the formal right to operate a press at the university; the chancellor, Robert Dudley, 1st Earl of Leicester, pleaded Oxford's case. Some royal assent was obtained, since the printer Joseph Barnes began work, a decree of Star Chamber noted the legal existence of a press at "the universitie of Oxforde" in 1586. Oxford's chancellor, Archbishop William Laud, consolidated the legal status of the university's printing in the 1630s. Laud envisaged a unified press of world repute.
Oxford would establish it on university property, govern its operations, employ its staff, determine its printed work, benefit from its proceeds. To that end, he petitioned Charles I for rights that would enable Oxford to compete with the Stationers' Company and the King's Printer, obtained a succession of royal grants to aid it; these were brought together in Oxford's "Great Charter" in 1636, which gave the university the right to print "all manner of books". Laud obtained the "privilege" from the Crown of printing the King James or Authorized Version of Scripture at Oxford; this "privilege" created substantial returns in the next 250 years, although it was held in abeyance. The Stationers' Company was alarmed by the threat to its trade and lost little time in establishing a "Covenant of Forbearance" with Oxford. Under this, the Stationers paid an annual rent for the university not to exercise its full printing rights – money Oxford used to purchase new printing equipment for smaller purposes.
Laud made progress with internal organization of the Press. Besides establishing the system of Delegates, he created the wide-ranging supervisory post of "Architypographus": an academic who would have responsibility for every function of the business, from print shop management to proofreading; the post was more an ideal than a workable reality, but it survived in the loosely structured Press until the 18th century. In practice, Oxford's Warehouse-Keeper dealt with sales and the hiring and firing of print shop staff. Laud's plans, hit terrible obstacles, both personal and political. Falling foul of political intrigue, he was executed in 1645, by which time the English Civil War had broken out. Oxford became a Royalist stronghold during the conflict, many printers in the city concentrated on producing political pamphlets or sermons; some outstanding mathematical and Orientalist works emerged at this time—notably, texts edited by Edward Pococke, the Regius Professor of Hebrew—but no university press on Laud's model was possible before the Restoration of the Monarchy in 1660.
It was established by the vice-chancellor, John Fell, Dean of Christ Church, Bishop of Oxford, Secretary to the Delegates. Fell regarded Laud as a martyr, was determined to honour his vision of the Press. Using the provisions of the Great Charter, Fell persuaded Oxford to refuse any further payments from the Stationers and drew
Ettore Majorana was an Italian theoretical physicist who worked on neutrino masses. On March 25, 1938, he disappeared under mysterious circumstances while going by ship from Palermo to Naples; the Majorana equation and Majorana fermions are named after him. In 2006, the Majorana Prize was established in his memory. There are several categories of scientists in the world. There is the first rank, those who make important discoveries, fundamental to scientific progress, but there are the geniuses, like Galilei and Newton. Majorana was one of these. Majorana was born in Sicily. Mathematically gifted, he was young when he joined Enrico Fermi's team in Rome as one of the "Via Panisperna boys", who took their name from the street address of their laboratory, his uncle Quirino Majorana was a physicist. He began his university studies in engineering in 1923 but switched to physics in 1928 at the urging of Emilio Segrè, his first papers dealt with problems in atomic spectroscopy. His first paper, published in 1928, was written when he was an undergraduate and coauthored by Giovanni Gentile, Jr. a junior professor in the Institute of Physics in Rome.
This work was an early quantitative application to atomic spectroscopy of Fermi's statistical model of atomic structure. In this paper and Gentile performed first-principles calculations within the context of this model that gave a good account of experimentally-observed core electron energies of gadolinium and uranium, of the fine structure splitting of caesium lines observed in optical spectra. In 1931, Majorana published the first paper on the phenomenon of autoionization in atomic spectra, designated by him as "spontaneous ionization"; this name has since become conventional, without the hyphen. Majorana earned his Laurea in physics at the University of Rome La Sapienza in 1929. In 1932, he published a paper in the field of atomic spectroscopy concerning the behaviour of aligned atoms in time-varying magnetic fields; this problem studied by I. I. Rabi and others, led to an important sub-branch of atomic physics, that of radio-frequency spectroscopy. In the same year, Majorana published his paper on a relativistic theory of particles with arbitrary intrinsic momentum, in which he developed and applied infinite dimensional representations of the Lorentz group, gave a theoretical basis for the mass spectrum of elementary particles.
Like most of Majorana's papers in Italian, it languished in relative obscurity for several decades. Experiments in 1932 by Irène Joliot-Curie and Frédéric Joliot showed the existence of an unknown particle that they suggested was a gamma ray. Majorana was the first to interpret the experiment as requiring a new particle that had a neutral charge and a mass about the same as the proton. Fermi told him to write an article. James Chadwick proved the existence of the neutron by experiment that year, he was awarded the Nobel Prize for this discovery. Majorana was known for not considering his work to be banal, he wrote only nine papers in his lifetime. "At Fermi's urging, Majorana left Italy early in 1933 on a grant from the National Research Council. In Leipzig, Germany, he met Werner Heisenberg. In letters he subsequently wrote to Heisenberg, Majorana revealed that he had found in him, not only a scientific colleague, but a warm personal friend." The Nazis had come to power in Germany. He worked on a theory of the nucleus which, in its treatment of exchange forces, represented a further development of Heisenberg's theory of the nucleus.
Majorana travelled to Copenhagen, where he worked with Niels Bohr, another Nobel Prize winner, a friend and mentor of Heisenberg. "In the fall of 1933, Majorana returned to Rome in poor health, having developed acute gastritis in Germany and suffering from nervous exhaustion. Put on a strict diet, he became harsh in his dealings with his family. To his mother, with whom he had shared a warm relationship, he had written from Germany that he would not accompany her on their customary summer vacation by the sea. Appearing at the institute less he soon was scarcely leaving his home. For nearly four years he shut himself off from friends and stopped publishing."During these years, in which he published few articles, Majorana wrote many small works on geophysics, electrical engineering and relativity. These unpublished papers, preserved in Domus Galileiana in Pisa have been edited by Erasmo Recami and Salvatore Esposito, he became a full professor of theoretical physics at the University of Naples in 1937, without needing to take an examination because of his "high fame of singular expertise reached in the field of theoretical physics", independently of the competition rules.
Majorana's last-published paper, in 1937, this time in Italian, was an elaboration of a symmetrical theory of electrons and positrons. In 1937, Majorana predicted that in the class of particles known as fermions there should be particles that are their own antiparticles; this is the so-called Majorana fermion. Solution of Majorana's equation yields particles that are their own anti-particle, now referred to as Majorana Fermions. In April 2012, some of what
A neutrino is a fermion that interacts only via the weak subatomic force and gravity. The neutrino is so named because it is electrically neutral and because its rest mass is so small that it was long thought to be zero; the mass of the neutrino is much smaller than that of the other known elementary particles. The weak force has a short range, the gravitational interaction is weak, neutrinos, as leptons, do not participate in the strong interaction. Thus, neutrinos pass through normal matter unimpeded and undetected. Weak interactions create neutrinos in one of three leptonic flavors: electron neutrinos, muon neutrinos, or tau neutrinos, in association with the corresponding charged lepton. Although neutrinos were long believed to be massless, it is now known that there are three discrete neutrino masses with different tiny values, but they do not correspond uniquely to the three flavors. A neutrino created with a specific flavor is in an associated specific quantum superposition of all three mass states.
As a result, neutrinos oscillate between different flavors in flight. For example, an electron neutrino produced in a beta decay reaction may interact in a distant detector as a muon or tau neutrino. Although only differences of squares of the three mass values are known as of 2016, cosmological observations imply that the sum of the three masses must be less than one millionth that of the electron. For each neutrino, there exists a corresponding antiparticle, called an antineutrino, which has half-integer spin and no electric charge, they are distinguished from the neutrinos by having opposite signs of lepton chirality. To conserve total lepton number, in nuclear beta decay, electron neutrinos appear together with only positrons or electron-antineutrinos, electron antineutrinos with electrons or electron neutrinos. Neutrinos are created by various radioactive decays, including in beta decay of atomic nuclei or hadrons, nuclear reactions such as those that take place in the core of a star or artificially in nuclear reactors, nuclear bombs or particle accelerators, during a supernova, in the spin-down of a neutron star, or when accelerated particle beams or cosmic rays strike atoms.
The majority of neutrinos in the vicinity of the Earth are from nuclear reactions in the Sun. In the vicinity of the Earth, about 65 billion solar neutrinos per second pass through every square centimeter perpendicular to the direction of the Sun. For study, neutrinos can be created artificially with nuclear reactors and particle accelerators. There is intense research activity involving neutrinos, with goals that include the determination of the three neutrino mass values, the measurement of the degree of CP violation in the leptonic sector. Neutrinos can be used for tomography of the interior of the earth; the neutrino was postulated first by Wolfgang Pauli in 1930 to explain how beta decay could conserve energy and angular momentum. In contrast to Niels Bohr, who proposed a statistical version of the conservation laws to explain the observed continuous energy spectra in beta decay, Pauli hypothesized an undetected particle that he called a "neutron", using the same -on ending employed for naming both the proton and the electron.
He considered that the new particle was emitted from the nucleus together with the electron or beta particle in the process of beta decay. James Chadwick discovered a much more massive neutral nuclear particle in 1932 and named it a neutron leaving two kinds of particles with the same name. Earlier Pauli had used the term "neutron" for both the neutral particle that conserved energy in beta decay, a presumed neutral particle in the nucleus; the word "neutrino" entered the scientific vocabulary through Enrico Fermi, who used it during a conference in Paris in July 1932 and at the Solvay Conference in October 1933, where Pauli employed it. The name was jokingly coined by Edoardo Amaldi during a conversation with Fermi at the Institute of Physics of via Panisperna in Rome, in order to distinguish this light neutral particle from Chadwick's heavy neutron. In Fermi's theory of beta decay, Chadwick's large neutral particle could decay to a proton and the smaller neutral particle: n0 → p+ + e− + νeFermi's paper, written in 1934, unified Pauli's neutrino with Paul Dirac's positron and Werner Heisenberg's neutron–proton model and gave a solid theoretical basis for future experimental work.
The journal Nature rejected Fermi's paper, saying that the theory was "too remote from reality". He submitted the paper to an Italian journal, which accepted it, but the general lack of interest in his theory at that early date caused him to switch to experimental physics. By 1934 there was experimental evidence against Bohr's idea that energy conservation is invalid for beta decay: At the Solvay conference of that year, measurements of the energy spectra of beta particles were reported, showing that there is a strict limit on the energy of electrons from each type of beta decay; such a limit is not expected if the conservation of energy is invalid, in which case any amount of energy would be statistically available in at least a few decays. The natural explanation of the beta decay spectrum as first measured in 1934 was that only a limited amount of en
In geometry and physics, spinors are elements of a vector space that can be associated with Euclidean space. Like geometric vectors and more general tensors, spinors transform linearly when the Euclidean space is subjected to a slight rotation. However, when a sequence of such small rotations is composed to form an overall final rotation, the resulting spinor transformation depends on which sequence of small rotations was used: unlike vectors and tensors, a spinor transforms to its negative when the space is rotated through a complete turn from 0° to 360°; this property characterizes spinors. It is possible to associate a similar notion of spinor to Minkowski space in which case the Lorentz transformations of special relativity play the role of rotations. Spinors were introduced in geometry by Élie Cartan in 1913. In the 1920s physicists discovered that spinors are essential to describe the intrinsic angular momentum, or "spin", of the electron and other subatomic particles. Spinors are characterized by the specific way.
They change in different ways depending not just on the overall final rotation, but the details of how that rotation was achieved. There are two topologically distinguishable classes of paths through rotations that result in the same overall rotation, as famously illustrated by the belt trick puzzle; these two inequivalent classes yield spinor transformations of opposite sign. The spin group is the group of all rotations keeping track of the class, it doubly covers the rotation group, since each rotation can be obtained in two inequivalent ways as the endpoint of a path. The space of spinors by definition is equipped with a linear representation of the spin group, meaning that elements of the spin group act as linear transformations on the space of spinors, in a way that genuinely depends on the homotopy class. In mathematical terms, spinors are described by a double-valued projective representation of the rotation group SO. Although spinors can be defined purely as elements of a representation space of the spin group, they are defined as elements of a vector space that carries a linear representation of the Clifford algebra.
The Clifford algebra is an associative algebra that can be constructed from Euclidean space and its inner product in a basis-independent way. Both the spin group and its Lie algebra are embedded inside the Clifford algebra in a natural way, in applications the Clifford algebra is the easiest to work with. After choosing an orthonormal basis of Euclidean space, a representation of the Clifford algebra is generated by gamma matrices, matrices that satisfy a set of canonical anti-commutation relations; the spinors are the column vectors. In three Euclidean dimensions, for instance, the Pauli spin matrices are a set of gamma matrices, the two-component complex column vectors on which these matrices act are spinors. However, the particular matrix representation of the Clifford algebra, hence what constitutes a "column vector", involves the choice of basis and gamma matrices in an essential way; as a representation of the spin group, this realization of spinors as column vectors will either be irreducible if the dimension is odd, or it will decompose into a pair of so-called "half-spin" or Weyl representations if the dimension is even.
What characterizes spinors and distinguishes them from geometric vectors and other tensors is subtle. Consider applying a rotation to the coordinates of a system. No object in the system itself has moved, only the coordinates have, so there will always be a compensating change in those coordinate values when applied to any object of the system. Geometrical vectors, for example, have components that will undergo the same rotation as the coordinates. More broadly, any tensor associated with the system has coordinate descriptions that adjust to compensate for changes to the coordinate system itself. Spinors do not appear at this level of the description of a physical system, when one is concerned only with the properties of a single isolated rotation of the coordinates. Rather, spinors appear when we imagine that instead of a single rotation, the coordinate system is rotated between some initial and final configuration. For any of the familiar and intuitive quantities associated with the system, the transformation law does not depend on the precise details of how the coordinates arrived at their final configuration.
Spinors, on the other hand, are constructed in such a way that makes them sensitive to how the gradual rotation of the coordinates arrived there: they exhibit path-dependence. It turns out that, for any final configuration of the coordinates, there are two inequivalent gradual rotations of the coordinate system that result in this same configuration; this ambiguity is called the homotopy class of the gradual rotation. The belt trick puzzle famously demonstrates two different rotations, one through an angle of 2π and the other through an angle of 4π, having the same final configurations but different classes. Spinors exhibit a sign-reversal that genuinely depends on this homotopy class; this distinguishes them from other tensors, none of which can feel the class. Spinors can be exhibited as concrete objects using a choice of Cartesian coordinates. In three Euclidean dimensions, for instance, spinors can be constructed by making a choice of Pauli spin matrices corresponding to the thre