Encyclopedia

Difference gel electrophoresis Difference gel electrophoresis (DIGE) is a form of gel electrophoresis where up to three different protein samples can be labeled with fluorescent dyes (for example Cy3, Cy5, Cy2) prior to two-dimensional electrophoresis. After the gel electrophoresis, the gel is scanned with the excitation wavelength of each dye one after the other.
Difference in differences Difference in Differences is a nonexperimental technique used in econometrics that measures the effect of a treatment at a given period in time. It is often used to measure the change induced by a particular treatment or event, though may be subject to certain biases (mean reversion bias, etc)
Difference polynomials In mathematics, in the area of complex analysis, the general difference polynomials are a polynomial sequence, a certain subclass of the Sheffer polynomials, which include the Newton polynomials, Selberg's polynomials, and the Stirling interpolation polynomials as special cases.
Difference set In combinatorics, a (v,k,lambda) difference set is a subset D of a group G such that the order of G is v, the size of D is k, and every nonidentity element of G can be expressed as a product d_1d_2^{-1} of elements of D in exactly lambda ways.
Differences between book and film versions of Charlie and the Chocolate Factory The following table depicts the differences between the book and film adaptations of Charlie and the Chocolate Factory by Roald Dahl. Dahl also initially wrote an early draft of the screenplay for the first movie, although 30% of the final shooting script was rewritten by David Seltzer.
Differences between Malay and Indonesian The differences between Malay (Bahasa Melayu) and Indonesian (Bahasa Indonesia) are slightly greater than those between British English and American English. They are mutually intelligible, but with differences in spelling, pronunciation and vocabulary.
Differences between Norwegian BokmĂĄl and Standard Danish Danish and Norwegian BokmĂĄl (by far the most common standard form of Norwegian) are very similar languages, but differences between them do exist. The languages are mutually comprehensible, with the primary differences being in pronunciation and in the sound system as a whole.
Differences between serbocroatian standard varieties The standard Serbian, Croatian, Montenegrin, and Bosnian languages differ in various aspects as outlined below. The various nuances do not present major obstacles in the communication; rather, they serve as the symbolic value that is assigned to them by their ethnically, religiously, socially and politically diverse group of speakers.
Differences between Spanish and Portuguese Spanish and Portuguese are two of the most widely spoken languages in the world today. Although they are closely related, to the point of having a moderate degree of mutual intelligibility, there are also important differences between them, which can pose difficulties for people acquainted with one of the languages who attempt to learn the other.
Differences between the Natural Rate of Unemployment and the NAIRU The Natural Rate of Unemployment (NRU) is the equilibrium level of unemployment to which the economy tends, as defined by Milton Friedman's misperception model of labour markets. This model assumes that, in the long-run, labour markets clear (i.
Differences in versions of The Hitchhiker's Guide to the Galaxy The Hitchhiker's Guide to the Galaxy has appeared in nine different versions since its original radio series in 1978. After the radio series, it was adapted for stage plays, novels, re-recorded on LP records, adapted again for television, a computer game, comic books, and finally a feature film.
Different Drum Different Drum is a 1967 song by Linda Ronstadt (from her days with the Stone Poneys), as well as the name of her 1974 compilation album. The song was her first hit single, and was written by Monkees member Michael Nesmith.
Different from the Others Different From The Others (German: Anders als die Andern) is a film which was produced in Germany during the largely liberal period which existed in that country between the world wars. It was first released in 1919 and stars Conrad Veidt and Reinhold SchĂĽnzel.
Different Skies Different Skies is the 1994 debut album by singer and songwriter Cara Jones who, up until its release, had operated solely as songwriter for other artists. The album established Jones as an artist in her own right, selling unusual amounts for an indy release and making her the darling of Tokyo radio.
Different Stars Different Stars is the second album by American rock band Trespassers William. It was originally self-released in 2002, released in the UK on Bella Union on 28 September 2002, and finally re-released with minor track changes on Nettwerk Records on 19 October 2004.
Different Strokes Different Strokes is a novel written by David Leo and published in 1993. Through a character of a reporter named Keith, the novel explores the life of two AIDS victims, and describes their suffering and the dilemmas they face in the course of their illness.
Differentiable manifold Informally, a differentiable manifold is a type of manifold which is in turn a kind of topological space that is similar enough to Euclidean space to allow one to do calculus. (It is important to note that differentiable can mean slightly different things in different contexts, such as continuously differentiable, k times differentiable, infinitely differentiable, also known as smooth, or complex differentiable, also known as holomorphic.
Differential (mechanics) In an automobile and other four-wheeled vehicles, a differential is a device, usually consisting of gears, for allowing each of the driving wheels to rotate at different speeds, while supplying equal torque to each of them.
Differential adhesion hypothesis The differential adhesion hypothesis is a theory of cell adhesion advanced by Malcom Steinberg in 1964to explain the mechanism by which heterotypic cells in mixed aggregates sort out into isotypic territories. Quantitative differences in homo and heterotypic adhesion are supposed to be sufficient to account for the phenomenon without the need to postulate cell type specific adhesion systems: fairly generally accepted, although some tissue specific cell adhesion molecules are now known to exist.
Differential algebra In mathematics, in the area of ring theory, differential rings, differential fields and differential algebras are rings, fields and algebras equipped with a derivation. The definitions of each are closely related and are all presented here.
Differential amplifier A differential amplifier is a type of an electronic amplifier that multiplies the difference between two inputs by some constant factor (the differential gain). A differential amplifier is the input stage of operational amplifiers, or op-amps, and emitter coupled logic gates.
Differential analyser The differential analyser was a mechanical analog computer designed to solve differential equations by integration, using wheel-and-disc mechanisms to perform the integration. It was one of the first advanced computing devices to be used operationally.
Differential association In criminology, Differential Association is a theory developed by Edwin Sutherland proposing that through interaction with others, individuals learn the values, attitudes, techniques, and motives for criminal behavior.
Differential Ability Scales The Differential Ability Scales (DAS) in the United States is a nationally normed, and individually administered battery of cognitive and achievement tests. It is comprised of a cognitive battery subdivided into two overlapping levels, a preschool level and school-age level, and a school achievement test that measures the basic skills in word reading, spelling and arithmetic.
Differential calculus over commutative algebras In mathematics the term differential calculus over commutative algebras refers to a part of commutative algebra. It is based on the observation that most concepts known from classical differential calculus can be formulated in purely algebraic terms.
Differential centrifugation Differential centrifugation is a procedure in which a homogenate is subjected to repeated centrifugations each time increasing the centrifugal force. Separation is based predominantly on particle mass and size with larger and heavier particles pelleting at lower centrifugal fields.
Differential coding In digital communications, differential coding is a technique used to provide unambiguous signal reception when using some types of modulation. It makes data to be transmitted to depend not only from the current bit (or symbol), but also from the previous one.
Differential cryptanalysis Differential cryptanalysis is a general form of cryptanalysis applicable primarily to block ciphers, but also to stream ciphers and cryptographic hash functions. In the broadest sense, it is the study of how differences in an input can affect the resultant difference at the output.
Differential encoding A differential encoding is an encoding in which signal significant conditions represent binary data, such as "0" and "1", and are represented as changes to succeeding values rather than with respect to a given reference.
Differential entropy Differential entropy (also referred to as continuous entropy) is a concept in information theory which tries to extend the idea of (Shannon) entropy, a measure of average surprisal of a random variable, to continuous probability distributions.
Differential equation In mathematics, a differential equation is an equation which involves the derivatives of an unknown function represented by a dependent variable. Many of the fundamental laws of physics, chemistry, biology and economics can be formulated as differential equations.
Differential evolution Differential Evolution (DE) is a method of mathematical optimization of multidimensional functions and belongs to the class of Evolution Strategy optimizers. DE finds the global minimum of a multidimensional, multimodal (i.
Differential extraction Differential extraction refers to the process by which two different types of cells' DNA can be extracted without mixing their contents. The most common application of this method is the extraction of DNA from vaginal epithelial cells and sperm cells from sexual assault cases in order to determine the DNA profiles of the victim and the perpetrator.
Differential Execution Differential execution refers to a method of executing a computer subroutine (See control flow) in such a way that differences from prior executions can be detected and acted upon. If the subroutine is one that walks through a data structure, differential execution can be used to detect changes in the data structure and produce notifications or take actions so as to communicate the changes.
Differential form A differential form is a mathematical concept in the fields of multivariate calculus, differential topology and tensors. The modern notation for the differential form, as well as the idea of the differential forms as being the wedge products of exterior derivatives forming an exterior algebra, was introduced by Elie Cartan.
Differential geometry of curves In mathematics, the differential geometry of curves provides definitions and methods to analyze smooth curves in Riemannian manifolds and Pseudo-Riemannian manifolds (and in particular in Euclidean space) using differential and integral calculus.
Differential GPS Differential Global Positioning System (DGPS) is an enhancement to Global Positioning System that uses a network of fixed ground based reference stations to broadcast the difference between the positions indicated by the satellite systems and the known fixed positions. These stations broadcast the difference between the measured satellite pseudoranges and actual (internally computed) pseudoranges, and receiver stations may correct their pseudoranges by the same amount.
Differential hardening Differential hardening is a method used in forging swords and knives to increase the hardness of the edge without making the whole blade brittle. To achieve this, the edge is cooled more rapidly than the spine by adding a heat insulator to the spine before quenching.
Differential ideal In the theory of differential forms, a differential ideal I is an algebraic ideal in the ring of smooth differential forms on a smooth manifold, in other words a graded ideal in the sense of ring theory, that is is further closed under exterior differentiation d. In other words, for any form α in I, the exterior derivative dα is also in I.
Differential identification Differential identification is a criminological theory which states that crime and/or deviance develops when the individual identifies more with the deviant group than with conforming members of society. For example, older criminals would serve as role models for younger criminals.
Differential inheritance Differential Inheritance is a common inheritance model used by prototype-based programming languages such as Io and NewtonScript. It operates on the principle that most objects are derived from other, more general objects, and only differ in a few small aspects; while usually maintaining a list of pointers internally to other objects which the object differs from.
Differential interference contrast microscopy Differential interference contrast microscopy (DIC), also known as Nomarski Interference Contrast (NIC) or Nomarski microscopy, is an optical microscopy illumination technique used to enhance the contrast in unstained samples. DIC works on the principle of interferometry to gain information about the optical density of the sample, to see otherwise invisible features.
Differential linearity In measurement systems differential linearity refers to a constant relation between the change in the output and input. For transducers if a change in the input produces a uniform step change in the output the tranducer possess differential linearity.
Differential Manchester encoding Differential Manchester encoding (also known as CDP; Conditional DePhase encoding) is a method of encoding data in which data and clock signals are combined to form a single self-synchronizing data stream. It is a differential encoding, using the presence or absence of transitions to indicate logical value.
Differential of the first kind In mathematics, differential of the first kind is a traditional term used in the theories of Riemann surfaces (more generally, complex manifolds) and algebraic curves (more generally, algebraic geometry), for everywhere-regular differential 1-forms. Given a complex manifold M, a differential of the first kind ω is therefore the same thing as a 1-form that is everywhere holomorphic; on an algebraic variety V that is non-singular it would be a global section of the coherent sheaf Ω1 of Kähler differentials.
Differential operator In mathematics, a differential operator is an operator defined as a function of the differentiation operator. It is helpful, as a matter of notation first, to consider differentiation as an abstract operation, accepting a function and returning another (in the style of a higher-order function in computer science).
Differential pulse voltammetry Differential pulse voltammetry is a kind of electrochemical measurement. It can be considered as a series of regular voltage pulses superimposed on a linearly changing voltage, in which the resulting current is measured between the ramped baseline voltage and the pulse voltage.
Differential rotation Differential rotation is seen if parts of a rotating object move with different angular velocity. (to put it short and non-scientific, parts at different distances from the rotation axis make a different number of rounds at a given time interval).
Differential scanning calorimetry Differential scanning calorimetry or DSC is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference are measured as a function of temperature. Both the sample and reference are maintained at very nearly the same temperature throughout the experiment.
Differential space–time code Differential space–time codes }} }} are a way of transmitting data in wireless communications. They are a form of space–time code that does not need to know the channel impairments at the receiver in order to be able to decode the signal.
Differential sticking Differential sticking is a problem that occurs when drilling a well with a greater well bore pressure than formation pressure, as is usually the case. The drill pipe is pressed against the wellbore wall so that part of its circumference will see only reservoir pressure, while the rest will continue to be pushed by wellbore pressure.
Differential structure In mathematics, an n-dimensional differential structure (or differentiable structure) on a set M makes it into an n-dimensional differential manifold, which is a topological manifold with some additional structure that allows us to do differential calculus on the manifold. If M is already a topological manifold, we require that the new topology be identical to the existing one.
Differential technological development Differential technological development is a strategy proposed by transhumanist philosopher Nick Bostrom in which societies would seek to influence the sequence in which emerging technologies developed. On this approach, societies would strive to retard the development of harmful technologies and their applications, while accelerating the development of beneficial technologies, especially those that offer protection against the harmful ones.
Differential thermal analysis A technique, which shares much in common with Differential scanning calorimetry, is differential thermal analysis or DTA. In this technique it is the heat flow to the sample and reference that remains the same rather than the temperature.
Differential TTL Differential TTL is a type of binary electrical signalling based on the TTL (transistor-transistor logic) standard. Normal TTL signals are single-ended, which means that each signal consists of a voltage on one wire, referenced to a system ground.
Differential variational inequality Differential variational inequalities (DVI's)were first formally introduced by Pang and Stewart, whose definition should not be confused with the differential variational inequality used in Aubin and Cellina (1984).
Differential wheeled robot A differential wheeled robot is a mobile robot whose movement is based of two separately driven wheels placed on either side of the robot body. It can thus change its direction by varying the relative rate of rotation of its wheels and hence does not require an additional steering motion.
Differentiated Bertrand competition As a solution to the Bertrand paradox (economics) it has been suggested that each firm produces a somewhat differentiated product and consequently faces a demand curve that is downward-sloping for all levels of the firm's price. An increase in a competitor's price is represented as an increase (for example, an upward shift) of the firm's demand curve.
Differentiated instruction Differentiated instruction (sometimes referred to as differentiated learning) is a way of thinking about teaching and learning. It means using a variety of instructional strategies that address diverse student learning needs.
Differentiated service (design pattern) Differentiated Service is a design pattern for business services and software, in which the service varies automatically according to the identity of the consumer and/or the context in which the service is used. Sometimes known as Smart Service or Context-Aware Service.
Differentiated services This article is on differentiated services within communication networks. For a related concept used as a design pattern for business applications (including smart services and context-aware services) see Differentiated service (design pattern).
Differentiation (linguistics) Differentiation in semantics is defined by Löbner (2002) as a meaning shift reached by "adding concepts to the original concepts". His example is James Joyce is hard to understand, where understand is differentiated from "perceiving the meaning" to "interpret the text meaning".
Differentiation in Fréchet spaces In mathematics, in particular in functional analysis and nonlinear analysis, it is possible to define the derivative of a function between two Fréchet spaces. This notion of differentiation is significantly weaker than the derivative in a Banach space.
Differintegral In mathematics, the differintegral is the combined differentiation/integration operator used in fractional calculus. The operator does not define a separate function, but is a notation style for taking both the fractional derivative and the fractional integral of the same expression.
Difficult Run Difficult Run, despite its name, is a streamMap of the watershed of Difficult Run located in Northern Virginia, a tributary of the Potomac River, in the United States. The term run, for stream, is common usage in this part of Virginia; another stream is better known in American Civil War History: Bull Run.
Diffie-Hellman key exchange Diffie-Hellman (D-H) key exchange is a cryptographic protocol that allows two parties that have no prior knowledge of each other to jointly establish a shared secret key over an insecure communications channel. This key can then be used to encrypt subsequent communications using a symmetric key cipher.
Diffie-Hellman problem The Diffie-Hellman problem (DHP) is the name of a specific problem in cryptography that was first proposed by Whitfield Diffie and Martin Hellman. The DHP is a problem that is assumed to be difficult to do, and some cryptography schemes are variants of the problem.
Difflugia Difflugia is one of several genera of amoebozoa that produce shells or tests from granules of sand. These are swallowed by the cell and during the process of budding or fission they pass into the daughter, where they are joined by organic cement.
Difford & Tilbrook Difford & Tilbrook was the name under which New Wave songwriters Chris Difford and Glenn Tilbrook recorded and toured following the 1982 breakup of their band, Squeeze. That band reunited in 1985, after only one self-titled album had been released under the Difford & Tilbrook moniker.
Diffraction Diffraction refers to various phenomena associated with wave propagation, such as the bending, spreading and interference of waves emerging from an aperture. It occurs with any type of wave, including sound waves, water waves, electromagnetic waves such as light and radio waves, and matter displaying wave-like properties according to the wave–particle duality.
Diffraction grating In optics, a diffraction grating is a reflecting or transparent element, whose optical properties are periodically modulated. Most commonly the diffraction gratings are realized as fine parallel and equally spaced grooves or rulings on material surface.
Diffuse knapweed Diffuse knapweed (Centaurea diffusa), also known as white knapweed, is a member of the Genus Centaurea in the Family Asteraceae. It is native to Asia Minor (Turkey, Syria), the Balkans, (Bulgaria, Greece, Romania), Ukraine, and southern Russia.
Diffuse optical imaging Diffuse optical imaging (DOI) or diffuse optical tomography (DOT) is a medical imaging modality which uses near infrared light to generate images of the body. The technique measures the optical absorption of haemoglobin, and relies on the absorption spectrum of haemoglobin varying with its oxygenation status.
Diffuse sky radiation Diffuse sky radiation is solar radiation reaching the earth's surface after having been scattered from the direct solar beam by molecules or suspensoids in the atmosphere. Also called skylight, diffuse skylight, or sky radiation.
Diffuser (automotive) A diffuser, in an automotive context, is usually a shaped section of the car underbody which improves the car's aerodynamic properties by enhancing the transition between the high-velocity airflow underneath the car and the much slower freestream airflow of the ambient atmosphere. It works by providing a space for the underbody airflow to decelerate and expand so that the boundary between the car's airflow and "external" airflow is less turbulent, and it also provides a degree of "wake infill" (the wake being a turbulent area of low pressure that is caused by the passage of the vehicle through the air; this can cause pressure drag).
Diffuser (breathing set part) A diffuser is a device fitted over an underwater breathing set's blowoff hole to break up the resulting bubbles very small so they will not be seen from out of the water. They are mostly needed in frogman-type diving operations where secrecy is needed, and in marine biology to avoid scaring fish which are being studied.
Diffuser (optics) In optics a diffuser is any device that [or spreads out or scatters light in some maner. Optical diffusers use different methods to diffuse light and can include ground glass] diffusers, holographic diffusers, opal diffusers, and greyed glass diffusers.
Diffuser (sewage) An Air Diffuser or Membrane Diffuser is an aeration device typically in the shape of a disc, tube or plate, which is used to transfer oxygen into sewage or industrial wastewater. Oxygen is required by bacteria resident in the water to break down the pollutants.
Diffuser (thermodynamics) A diffuser is the mechanical device that is designed to control the characteristics of a fluid at the entrance to a thermodynamic open system. Diffusers are used to slow the fluid's velocity and to enhance its mixing into the surrounding fluid.
Diffusion Diffusion is the net action of matter (particles or molecules), heat, momentum, or light whose end is to minimize a concentration gradient. The process of diffusion, therefore, minimizes thermodynamic Gibbs free energy (though, it is not a chemical reaction), and is thus a spontaneous process (more familiarly known as a "passive" form of transport, rather than "active").
Diffusion (anthropology) The term 'diffusion' or diffusionism is used in cultural anthropology to describe the spread of cultural items — such as ideas, styles, religions, technologies, etc. — between individuals, whether within a single culture or from one culture to another.
Diffusion barrier A diffusion barrier is a thin layer (usually micrometres thick) of metal usually placed between two other metals. It is done to act as a “barrier” to protect either one of the metals from corrupting the other.
Diffusion capacity In biology, diffusion capacity is a measurement of the lung's ability to absorb and excrete gases, notably, oxygen and carbon dioxide. It is part of a comprehensive test series of lung function called pulmonary function testing.
Diffusion equation The diffusion equation is a partial differential equation, which describes the density fluctuations in a material undergoing diffusion. It is also used in population genetics to describe the 'diffusion' of alleles in a population.
Diffusion Monte Carlo Diffusion Monte Carlo (DMC) is a quantum Monte Carlo method that utilizes a Green function to solve the Schrödinger equation. DMC is potentially numerically exact, meaning that it can find the exact ground state energy within a given error for any quantum system.
Diffusion pump Diffusion pumps are a type of vacuum pump designed to achieve better vacuum pressures than possible by use of mechanical pumps alone. They use a high speed jet of fluid to direct residual gas molecules in the pump throat down into the bottom of the pump and out the exhaust.
Diffusion tensor imaging Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that enables the measurement of the restricted diffusion of water in tissue. The principal application is in the imaging of white matter
Diffusion-limited aggregation Diffusion-limited aggregation (DLA) is the process whereby particles undergoing a random walk due to Brownian motion cluster together to form aggregates of such particles. This theory, proposed by Witten and Sander in 1981 T.
Difunta Correa The Deceased [Deolinda] Correa (in Spanish La Difunta Correa) is a semi-pagan mythical figure in folk-religion, for which a number of people in Argentina, especially among the popular classes, feel a great devotion. It has spread, in a limited way, to neighbouring countries such as Uruguay and Chile.
Dig (I Mother Earth album) Dig is the debut album by the Canadian alternative rock band I Mother Earth, released by Capitol and EMI on August 10, 1993. It went Gold in Canada in its initial run, and today stands at Double Platinum in Canada.
Dig (Incubus song) "Dig" will be the second single released by American alternative rock band Incubus from their sixth studio album Light Grenades (2006). The band wants fans to help create the music video for the song and they have started a contest called "I Dig Incubus".
Dig Allen The "Dig" Allen, Space Explorer series consisted of six juvenile science fiction books written in the late 1950s and early 1960s by Joseph Greene, the originator of the Tom Corbett, Space Cadet television show.
Dig Circus Dig Circus was a Canadian alternative rock band in the 1990s. Although they were popular on the Queen Street West scene in Toronto, the band broke up in the mid-1990s without having achieved mainstream success.
Dig It "Dig It" is a song by The Beatles featured on their album Let It Be. The 50-second version on the album is an extract taken from a 12-minute jam (recorded at the Get Back/Let It Be Sessions in January 1969 at Apple Studio), which evolved from a loose "Twist and Shout" jam.
Diga Leka Diga Leka is one of the 180 woredas in the Oromia Region of Ethiopia. Part of the Misraq Welega Zone, Diga Leka is bordered on the south by an exclave of the Benishangul-Gumaz Region, on west by the Didessa River which separates it from the Illubabor Zone on the southwest and the Mirab Welega Zone on the west, on the north by Sasiga, on the northeast by Guto Wayu and on the southeast by Jimma Arjo.
Digable Planets Digable Planets is an alternative hip hop group composed of Ishmael "Butterfly" Butler, Craig "Doodlebug" Irving, and Mary Ann "Ladybug Mecca" Vieira. They were backed by Silkworm, who later embarked on a solo career under the name King Britt.
Digbeth Institute The Digbeth Institute is a 2,000 capacity music venue in Digbeth, Birmingham, England which has been synonymous in the development of the British rave music and drum and bass scene. A former church and theatre, the venue is now called the Sanctuary and was the original home of Godskitchen`s weekly club nights.
Digby (electoral district) Digby was a federal electoral district in Nova Scotia, Canada, that was represented in the Canadian House of Commons from 1867 to 1917. It was created as part of the British North America Act of 1867, and was abolished in 1914 when it was redistributed into Digby and Annapolis and Yarmouth and Clare ridings.
Digby and the Lake Monster Digby and the Lake Monster (2006) is a children's picture book written and illustrated by Dom Cioffi. It tells the story of Digby, a young boy living in New England who discovers a strange creature in the lake near his house.
Digby Anderson Digby Anderson is the founder and former Director of the Social Affairs Unit, a public policy organization/economic think tank created by Anderson in 1980. In addition to this role Anderson served as a long-time contributor to and editor of several conservative American and British journals of thought, including The Spectator and Daily Telegraph-where he served as a resident food critic, as well as the The American Spectator, The New Criterion, and National Review.

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