All articles starting with Q
2,252 articles
Quanrong sack of Haojing and the fall of Western Zhou
The Quanrong sack of Haojing (犬戎之亂) was the 771 BC capture of the Zhou capital by the Quanrong, Shen, and Zeng, killing King You and ending Western Zhou.
Quanta Computer (广达电脑)
Quanta Computer (广达电脑) is a Taiwanese manufacturer of notebook computers and AI servers, founded in 1988 and headquartered in Taoyuan. It is the world's largest notebook maker.
Quantá Crews
Quantá Crews is an American politician, minister, and real estate appraiser, a Democrat in the Arizona House of Representatives appointed to the 26th district seat in 2023.
Quanta Services
Quanta Services is an American specialty infrastructure contractor that designs, builds, and maintains electric power networks, renewable energy, and pipelines, with $28.5 billion of 2025 revenue.
Quantal neurotransmitter release
Quantal neurotransmitter release is the discharge of neurotransmitter in discrete packets, each the contents of one synaptic vesicle, proposed by Bernard Katz and José del Castillo in 1954.
Quantale
A quantale is a complete lattice equipped with an associative binary operation distributing over arbitrary joins in each variable, introduced by C. J. Mulvey to extend locales non-commutatively for quantum logic.
Quantenna Communications
Quantenna Communications was a California fabless semiconductor company founded in 2005 that designed high-performance Wi-Fi chipsets, listed on Nasdaq in 2016, and was acquired by ON Semiconductor in 2019.
Quantic Dream
Quantic Dream: French video game developer founded by David Cage in Paris, 2 May 1997; maker of Omikron, Heavy Rain, Beyond: Two Souls, Detroit: Become Human; NetEase-owned since 2022; Paris and Montreal studios.
Quantico (TV series)
Quantico is an ABC drama (2015-2018) created by Joshua Safran, starring Priyanka Chopra Jonas as FBI recruit Alex Parrish, framed for a Grand Central bombing; three seasons, canceled at 2.3 million viewers per episode.
Quantico, Virginia
Quantico, Virginia: a tiny incorporated Prince William County town, the only US town completely surrounded by a military base, Marine Corps Base Quantico, accessible only through base security gates.
Quantified modal logic
Quantified modal logic (QML) combines a propositional modal logic with first-order quantifiers; the Barcan Formula is valid under constant domains but fails under the varying domains Kripke introduced in 1963.
Quantifier (logic)
A quantifier, also called a logical quantifier, is an operator in predicate logic, such as "for all" or "there exists", expressing how many objects satisfy a formula.
Quantifier elimination
Quantifier elimination is a property of first-order theories in model theory: every formula is equivalent, over the theory, to one with no quantifiers, which can yield decidability.
Quantik
Quantik (Gigamic, 2019, designer Nouri Khalifa) is a two-player perfect-information abstract strategy game on a 4x4 board; players place two each of four shapes, and the fourth different shape in a row, column, or quadrant wins. Not the quantum-physics game genre.
Quantile
A quantile is a value below which a specified fraction of a probability distribution or data sample falls; the median is the 0.5 quantile, and quartiles, deciles, and percentiles are other named cases.
Quantile function
The quantile function of a random variable, also called the inverse cumulative distribution function, maps a probability p to the smallest value x where the CDF reaches p, the basis of inverse transform sampling.
Quantile mapping
Quantile mapping is a statistical bias correction method that adjusts model or sensor data so its quantiles match an observed reference distribution, widely used in hydrologic modeling.
Quantile regression
Quantile regression is a statistical method introduced by Roger Koenker and Gilbert Bassett in 1978 that fits regression models to quantiles, such as the median, of a response.
Quantinuum
Quantinuum is an American quantum computing company formed in 2021 from Honeywell Quantum Solutions and Cambridge Quantum, headquartered in Broomfield, Colorado, and traded on Nasdaq as QNT.
Quantitative computed tomography
Quantitative computed tomography (QCT) is a medical imaging technique that converts CT measurements into calibrated bone density values in mg/cm³, used to diagnose and monitor osteoporosis and enable opportunistic screening.
Quantitative content analysis
Quantitative content analysis is a social science research method that assigns communication content to categories by explicit rules, then uses statistics to describe messages and infer about their context.
Quantitative coronary angiography
Quantitative coronary angiography (QCA) is an image-analysis method that measures coronary artery dimensions and stenosis severity from X-ray angiograms, and is the standard objective measure used in core laboratories and for stent sizing.
Quantitative CT
Quantitative CT (QCT) is a set of computational methods that extract numerical measurements, chiefly volumetric bone mineral density, from CT images rather than visual reading.
Quantitative descriptive analysis
Quantitative descriptive analysis (QDA) is a sensory evaluation method in which a small trained panel, typically 10 to 12 subjects, rates the intensity of product attributes on line scales.
Quantitative easing
Quantitative easing (QE) is a central bank policy of creating reserves to buy long-dated assets, lowering long-term interest rates when short rates are near zero.
Quantitative electroencephalography
Quantitative electroencephalography (qEEG) is the mathematical processing of digitally recorded EEG, using spectral analysis and normative comparison to supplement, never replace, visual reading by a trained electroencephalographer.
Quantitative immunofluorescence
Quantitative immunofluorescence is a microscopy method that measures fluorescence intensity from antibody-labeled targets to quantify protein abundance, localization, and expression differences in cells and tissues.
Quantitative insulin sensitivity check index
The quantitative insulin sensitivity check index (QUICKI) is a fasting index, described in 2000, that estimates insulin sensitivity from fasting insulin and glucose for research use.
Quantitative light-induced fluorescence
Quantitative light-induced fluorescence (QLF) is a non-invasive dental diagnostic method that uses blue light to make tooth tissue fluoresce, quantifying demineralization to detect and monitor early caries lesions.
Quantitative magnetic resonance imaging
Quantitative magnetic resonance imaging (qMRI) is a family of MRI techniques that measure tissue properties such as relaxation times and diffusion as numerical values in physical units.