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Mixed data sampling regression
Mixed data sampling (MIDAS) regression is an econometric method that regresses a low-frequency variable, such as quarterly GDP growth, on more frequently sampled predictors, like monthly indicators, using parsimonious distributed lag weights.
Mixed design (statistics)
A mixed design is an experimental design combining a between-groups factor with a within-subjects repeated-measures factor, also called a split-plot design and commonly used in pretest-posttest studies.
Mixed finite element method
A mixed finite element method is a Galerkin technique approximating two or more coupled fields of a partial differential equation at once, such as velocity and pressure.
Mixed layer
The mixed layer, also called the isothermal layer, is the turbulent upper ocean where wind and cooling make temperature, salinity, and density nearly uniform, typically tens of meters deep.
Mixed logit
Mixed logit, also called the mixed logit model, is a discrete choice model in which utility coefficients vary randomly over decision makers, relaxing the limits of standard logit.
Mixed lubrication
Mixed lubrication is a lubrication regime in which the load is carried partly by lubricant film pressure and partly by asperity contact, occurring at film thickness ratios between 1 and 3.
Mixed Methods Appraisal Tool
The Mixed Methods Appraisal Tool (MMAT) is a checklist for appraising the methodological quality of qualitative, quantitative, and mixed methods studies, developed at McGill University and current since 2018.
Mixed methods research
Mixed methods research is a social science research approach that combines qualitative and quantitative data collection, analysis, and integration within a single study, requiring at least one point of integration between the two strands.
Mixed model
A mixed model is a statistical model combining fixed effects, constant across the population, with random effects attached to units, used for clustered and longitudinal data.
Mixed radix
Mixed radix, also called mixed base, is a positional numeral system in which each digit position has its own radix, unlike the single fixed base of decimal.
Mixed state
A mixed state in quantum mechanics is a statistical ensemble of pure states with probabilities p_i, described by a density matrix; it differs fundamentally from a quantum superposition.
Mixed volume
Mixed volume is a multilinear extension of volume to convex bodies, defined as a coefficient of the volume polynomial; it is central to convex geometry.
Mixed-dimensional van der Waals heterostructures
Mixed-dimensional van der Waals heterostructures are layered systems combining 2D materials like graphene with quantum dots, nanowires, or bulk crystals via van der Waals forces.
Mixed-halide perovskite MAPb(I1-xBrx)3
MAPb(I1−xBrx)3 is a mixed-halide lead perovskite whose bandgap is tuned continuously between MAPbI3 and MAPbBr3, widely used in perovskite-silicon tandem solar cells despite light-induced phase segregation, the Hoke effect.
Mixed-integer optimization
Mixed-integer optimization is a family of mathematical optimization methods for problems combining continuous variables with integer or discrete values, solved by branch-and-bound and cutting planes over relaxations.
Mixed-integer quadratic programming
Mixed-integer quadratic programming (MIQP) is an optimization method that minimizes a quadratic objective subject to linear constraints, where some variables must take integer values and others stay continuous.
Mixed-metal metal–organic frameworks
Mixed-metal metal–organic frameworks (MM-MOFs), also called bimetallic or multivariate MOFs, contain at least two different metal ions as nodes, combining electronic, magnetic, and geometric properties.
Mixed-mode chromatography
Mixed-mode chromatography is a liquid chromatography technique in which one stationary phase provides two or more retention mechanisms, typically reversed-phase combined with ion exchange, tuned by pH, salt, and solvent.
Mixed-mode fracture
Mixed-mode fracture is crack growth under a combination of fracture modes, mode I opening, mode II sliding, and mode III tearing; real structural cracks are rarely loaded in a single pure mode.
Mixed-phase cloud
A mixed-phase cloud is a cloud containing supercooled liquid droplets and ice crystals together, found from the tropics to the poles and important for precipitation and climate.
Mixing (mathematics)
Mixing is a property of measure-preserving dynamical systems in which past and future events become statistically independent over time, one level of the ergodic hierarchy.
Mixing length theory
Mixing length theory (MLT) is a local, time-independent model of convection in stars, in which a fluid parcel rises a characteristic distance before dissolving and releasing its excess heat.
Mixing ratio
Mixing ratio is the ratio of the mass of water vapor to the mass of dry air in moist air, usually quoted in grams of vapor per kilogram.
Mixing regime
A mixing regime is the annual pattern of vertical mixing and thermal stratification in a lake, classified by how often and how completely its water circulates each year.
Mixing time of Markov chains
The mixing time of a Markov chain is the number of steps needed for its distribution to become close to its stationary distribution, regardless of the starting state.
Mixmaster universe
The Mixmaster universe is an anisotropic cosmological model of Bianchi type IX introduced by Charles Misner in 1969, with an oscillatory approach to the big bang.
Mixture
A mixture is a phase containing more than one substance whose components can be separated by physical changes, unlike a compound, and may be homogeneous or heterogeneous.
Mixture design
A mixture design is a design of experiments in which the factors are the proportions of components in a blend, constrained to be non-negative and to sum to one.
Mixture distribution
A mixture distribution is a probability distribution formed as a weighted combination of component distributions, equivalent to choosing a component at random and then sampling from it.
Mixture model
A mixture model is a probability model in which data are assumed to come from several component distributions, weighted so the weights sum to one.