All articles starting with D
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Dereverberation
Dereverberation is a signal processing method that removes reverberation, the delayed reflections of sound in a room, from recordings to improve speech clarity and recognition.
Derg (ደርግ)
Derg (ደርግ), Amharic for committee, the Ethiopian military junta (PMAC) that ruled 1974–1991 under Mengistu Haile Mariam, known for land reform, the Red Terror, the Ogaden War, the 1984–85 famine, and defeat by the EPRDF.
Dergâh
Dergâh was an Istanbul idea, art, and literature magazine published every fifteen days from 1921 to 1923, centered on Yahya Kemal and influential in Turkish literature.
Derge Parkhang
Derge Parkhang (德格印经院), also called the Derge Printing House, is a woodblock printing house in Derge, Sichuan, founded in 1729, holding about 300,000 hand-carved woodblocks.
Deriba Merga
Deriba Merga (Deriba Merga Ejigu), Ethiopian marathon runner, fourth at the 2008 Beijing Olympics, winner of the 2009 Houston (2:07:52 CR) and Boston (2:08:42) Marathons, personal best 2:06:38.
Deric Augustine
Deric Augustine (born 1990) is an American actor from New Orleans known as Muhammad Ali in Godfather of Harlem and Officer Miles Penn on The Rookie, promoted to series regular in Season 8; also author of the YA fantasy novel Nawlins.
Derick T Wade
Derick T Wade, also known as Derick Wade, is a physician in rehabilitation medicine known for his 1983 Lancet paper on stroke care and work defining rehabilitation.
Derik Queen
Derik Emanuel Queen (born 2004, Baltimore) is an NBA center for the New Orleans Pelicans, nicknamed "Baby Jokić". One-season Maryland star, drafted 13th overall in 2025 by Atlanta and traded to New Orleans; 2025-26 All-Rookie.
Deriner Dam
Deriner Dam is a 249 m double-curvature concrete arch dam on the Çoruh River, 5 km upstream of Artvin, Turkey, feeding a 670 MW underground hydroelectric plant.
Derinkuyu underground city
Derinkuyu Underground City (Derinkuyu Yeraltı Şehri) is a multi-level rock-cut refuge in Cappadocia, Nevşehir Province, Turkey, about 85 m deep with eight levels open, 52 ventilation shafts, rolling stone doors, and an estimated capacity of 20,000 people.
Derivation (differential algebra)
In differential algebra, a derivation is a linear map on an algebra obeying the Leibniz product rule, the algebraic abstraction of differentiation begun by Joseph Fels Ritt in the 1930s.
Derivation of the Einstein field equations
The derivation of the Einstein field equations is how general relativity arrives at its central equation relating spacetime curvature to matter, by physical argument or by extremizing the Einstein-Hilbert action.
Derivation of the Navier–Stokes equations
The derivation of the Navier–Stokes equations is the chain of steps producing the governing equations of viscous flow, derived by Navier and Stokes in the early 1800s.
Derivation of the Schwarzschild solution
The derivation of the Schwarzschild solution is the calculation yielding the first exact solution of the Einstein field equations, found by Karl Schwarzschild in 1915.
Derivations of the Lorentz transformations
The derivations of the Lorentz transformations are the mathematical arguments yielding the equations relating space and time coordinates between inertial frames, from Einstein's 1905 postulates and later symmetry-only routes.
Derivative
The derivative of a function is the limit of its average rate of change over shrinking intervals, giving the instantaneous rate of change and tangent slope at a point.
Derivative (finance)
A derivative is a financial contract whose value is derived from an underlying asset, rate, or index; the main types are forwards and futures, options, and swaps.
Derivative spectrophotometry
Derivative spectrophotometry is an analytical technique that converts an absorption spectrum into its mathematical derivative to resolve overlapping peaks, suppress background absorption, and quantify analytes in mixtures.
Derivative work
Derivative work: a copyright work based on preexisting works (translations, adaptations, arrangements) under 17 U.S.C. §§101, 103, 106(2) and Berne Article 2(3); protection covers only new authorship, and Warhol v. Goldsmith (2023) bounds fair use.
Derivative-free optimization
Derivative-free optimization (DFO) is a class of numerical algorithms that minimize or maximize a function using only its values, when the function is a black-box simulation with no derivative information.
Derivatives market
A derivatives market is the set of venues and dealer networks where contracts valued against underlying assets like interest rates, currencies, and commodities are traded, cleared, and settled.
Derivatization
Derivatization is an analytical chemistry technique that chemically modifies a compound, improving its volatility, detectability, or stability for instrumental analysis, most often chromatography with mass spectrometry.
Dérive
The dérive (drift) is a Situationist practice of aimless urban wandering defined by Guy Debord in 1956, tied to psychogeography, group drifts of two or three, and later walking-art and digital uses.
Derived algebraic geometry
Derived algebraic geometry, or DAG, is a branch of mathematics studying derived schemes and stacks, classical schemes enhanced with homotopical, higher categorical data, with foundations laid in the 2000s by Toën, Vezzosi, and Lurie.
Derived category
A derived category is a mathematical construction that replaces an abelian category by a category of chain complexes, invented by Grothendieck and Verdier in the early 1960s.
Derived demand
Derived demand is demand for a good or factor of production that exists because of demand for something it helps produce, a concept introduced by Alfred Marshall.
Derived functor
A derived functor, in left and right variants, is a homological algebra construction measuring how far a functor fails to be exact, computed by applying it to a projective or injective resolution and taking homology.
Derk Boswijk
Derk Boswijk is a Dutch politician of the Christian Democratic Appeal who became State Secretary for Defence in 2026, after serving in the House of Representatives.
Derk Cheetwood
Derk Cheetwood (born 1973, Bowling Green, Ohio) is an American actor, Max Giambetti on General Hospital from 2002, brother of Drew Cheetwood, films The Postman, U-571, Frailty.
Derlin
Derlins (Der1, Derlin-1/2/3) are inactive rhomboid-like ER membrane proteins mediating ERAD retrotranslocation of misfolded proteins to the proteasome, partners of Hrd1 and p97, exploited by viruses and toxins and linked to cancer and liver disease.