All articles starting with D

Difference gel electrophoresis

Difference gel electrophoresis, also called two-dimensional difference gel electrophoresis (DIGE), is a proteomics method that labels protein samples with fluorescent dyes and runs them on one gel.

Difference in differences

Difference in differences (DiD), also called diff-in-diff, is a quasi-experimental method estimating causal effects by comparing treated and untreated groups' changes over time, first applied by John Snow in 1855.

Difference of two squares

The difference of two squares is the algebraic identity a² − b² = (a − b)(a + b), one of the most recognizable factoring patterns in elementary algebra.

Difference set

A difference set is a subset of a finite group whose pairwise quotients represent every nonidentity element exactly λ times, used to build symmetric block designs.

Difference spectroscopy

Difference spectroscopy is a spectroscopic technique that records the difference between a sample spectrum and a reference spectrum, isolating small absorption changes across UV-Vis, infrared, and Raman methods.

Difference-frequency generation

Difference-frequency generation (DFG) is a second-order nonlinear optical process in which two frequencies in a non-centrosymmetric crystal produce radiation at their difference, a key route to tunable mid-infrared output.

Different Class

Different Class (Pulp album, released in Japan as Common People), fifth studio album by the Sheffield Britpop band, 30 October 1995 on Island; UK number 1, 1995 Mercury Music Prize winner, lead single "Common People".

Different Seasons

Different Seasons (1982, Viking Press) is Stephen King's four-novella collection pairing Shawshank Redemption, Apt Pupil, The Body, and The Breathing Method with the seasons; it inspired Stand By Me and the seven-time Oscar-nominated Shawshank film.

Sep 19, 2026

Different Touch

Different Touch (ডিফ্‌রেন্ট টাচ) is a Bangladeshi soft rock band formed in Khulna in the late 1980s, best known for 'Sraboner Megh Gulo Joro Holo Akashe'.

Differentiable architecture search

Differentiable architecture search (DARTS) is a neural architecture search method, described in 2018, that relaxes discrete architecture choices into a continuous form optimizable by gradient descent, cutting search cost to a few GPU days.

Differentiable function

A differentiable function, also called a derivable function or differentiable mapping, is a function with a derivative at each point of interest, the central hypothesis of differential calculus.

Differentiable manifold

A differentiable manifold, also called a smooth manifold, is a topological space locally resembling Euclidean space, equipped with a smooth structure allowing calculus, central to differential geometry.

Oct 22, 2026

Differentiable molecular simulation

Differentiable molecular simulation is a computational technique that backpropagates through molecular dynamics trajectories to optimize force field parameters, connecting molecular modeling to the optimization machinery of deep learning.

Differentiable optimization

Differentiable optimization embeds an optimization problem as a neural network layer: the forward pass solves it, and implicit differentiation of the optimality conditions supplies gradients for end-to-end training.

Differentiable programming

Differentiable programming is a programming paradigm in which programs are written so automatic differentiation, which applies the chain rule, computes exact gradients, allowing whole programs to be optimized end to end.

Differentiable simulation

Differentiable simulation is an approach to physics simulation in which the simulator is built from differentiable operations, supplying gradients for system identification, controller design, and policy learning.

Differential (mathematics)

In mathematics, a differential, also called a differential element, is the main linear part of a function's increment, denoted dy, introduced by Leibniz and published in 1684, and used today for approximation and error estimation.

Differential (mechanical device)

A differential, also called a differential gear train, is a three-shaft gear train in which one shaft's speed is the average of the other two, letting driving wheels rotate at different speeds when cornering.

Differential Ability Scales

The Differential Ability Scales (DAS), published in 1990, and its 2007 second edition, the DAS-II, are test batteries assessing cognitive abilities in children aged 2:6 to 17:11.

Differential algebra

Differential algebra is the branch of algebra studying rings and fields equipped with derivations, operations satisfying the formal rules of differentiation, founded by Joseph Fels Ritt.

Differential algebraic equation

A differential algebraic equation (DAE) is an equation combining differential equations with algebraic constraints, imposing instantaneous relations among variables; it is applied in circuit simulation, mechanics, and control.

Differential amplifier

A differential amplifier, or difference amplifier, is an electronic amplifier that amplifies the voltage difference between two inputs while rejecting voltage common to both, measured by its common-mode rejection ratio.

Differential analyser

The differential analyser, or Bush differential analyzer, is a mechanical analog computer for solving differential equations, first built by Vannevar Bush at MIT in 1931.

Differential calculus

Differential calculus is the branch of mathematics that studies how functions change through the derivative, which measures instantaneous rates of change and the slope of tangent lines.

Differential centrifugation

Differential centrifugation is a cell fractionation method that separates cell components by spinning a homogenate at stepwise increasing speeds, pelleting nuclei, mitochondria, and microsomes in sequence.

Differential coding

Differential coding is a data compression technique that stores values as differences from a reference or previous value, so correlated data becomes smaller and easier to compress.

Differential cross section

The differential cross section, written dσ/dΩ, gives the rate at which particles scatter into a given solid angle per unit incident flux, measured in barns per steradian.

Differential cryptanalysis

Differential cryptanalysis is a chosen-plaintext attack introduced by Eli Biham and Adi Shamir in 1991, the first published attack to break the full 16-round DES.

Differential diagnosis

Differential diagnosis: the systematic comparison of candidate conditions to determine which a patient has. Covers hypothesis generation, Bayesian ranking, diagnostic error rates (5.08% outpatient), checklists, and LLM tools like AMIE.