Matrix - AbsoluteAstronomy.com

Matrix (mathematics)
Matrix (mathematics)
In mathematics, a matrix is a rectangular array of numbers, symbols, or expressions. The individual items in a matrix are called its elements or entries. An example of a matrix with six elements isMatrices of the same size can be added or subtracted element by element...

, a mathematical object generally represented as an array of numbers
- Matrix calculus
  Matrix calculus
  In mathematics, matrix calculus is a specialized notation for doing multivariable calculus, especially over spaces of matrices, where it defines the matrix derivative. This notation was to describe systems of differential equations, and taking derivatives of matrix-valued functions with respect...
  
  , a notation for calculus operations on matrix spaces
- Identity matrix
  Identity matrix
  In linear algebra, the identity matrix or unit matrix of size n is the n×n square matrix with ones on the main diagonal and zeros elsewhere. It is denoted by In, or simply by I if the size is immaterial or can be trivially determined by the context...
- Similarity matrix
  Similarity matrix
  A similarity matrix is a matrix of scores which express the similarity between two data points. Similarity matrices are strongly related to their counterparts, distance matrices and substitution matrices.-Use in sequence alignment:...
  
  , which scores the similarity between two data points
- A number of bioinformatic related matrices, including:
  - Position-specific scoring matrix
    Position-specific scoring matrix
    A position weight matrix , also called position-specific weight matrix or position-specific scoring matrix , is a commonly used representation of motifs in biological sequences....
    
    , which represents a pattern or motif in biological sequences
  - Substitution matrix
    Substitution matrix
    In bioinformatics and evolutionary biology, a substitution matrix describes the rate at which one character in a sequence changes to other character states over time...
    
    , which estimates the rate at which each possible residue in a biological sequence changes to each other residue over time
  - PAM matrix, or Point Accepted Mutation matrix, used in scoring sequence alignments
  - BLOSUM
    BLOSUM
    The BLOSUM matrix is a substitution matrix used for sequence alignment of proteins. BLOSUM matrices are used to score alignments between evolutionarily divergent protein sequences. They are based on local alignments. BLOSUM matrices were first introduced in a paper by Henikoff and Henikoff...
    
    (BLOcks of Amino Acid SUbstitution Matrix), also used in scoring sequence alignments
Matrix (biology)
Matrix (biology)
In biology, matrix is the material between animal or plant cells, in which more specialized structures are embedded, and a specific part of the mitochondrion that is the site of oxidation of organic molecules. The internal structure of connective tissues is an extracellular matrix...

, with numerous meanings, often referring to a biological material where specialized structures are formed or embedded
- Extracellular matrix
  Extracellular matrix
  In biology, the extracellular matrix is the extracellular part of animal tissue that usually provides structural support to the animal cells in addition to performing various other important functions. The extracellular matrix is the defining feature of connective tissue in animals.Extracellular...
  
  , any material part of a tissue that is not part of any cell
- Mitochondrial matrix
  Mitochondrial matrix
  In the mitochondrion, the matrix contains soluble enzymes that catalyze the oxidation of pyruvate and other small organic molecules.The mitochondrial matrix also contains the mitochondria's DNA and ribosomes. The word "matrix" stems from the fact that this space is viscous, compared to the...
  
  , the inner part of a mitochondrion, where the Krebs cycle takes place
- Osteon
  Osteon
  The osteon, or Haversian system, is the fundamental functional unit of much compact bone. Osteons, roughly cylindrical structures that are typically several millimeters long and around 0.2mm in diameter, are present in many of the bones of most mammals, birds, reptiles, and amphibians.Each osteon...
  
  or bone matrix, a form of connective tissue found in bone
- Nuclear matrix
  Nuclear matrix
  In biology, the nuclear matrix is the network of fibres found throughout the inside of a cell nucleus and is somewhat analogous to the cell cytoskeleton...
  
  , an insoluble fraction of the cell nucleus
- Germinal matrix
  Germinal matrix
  In anatomy, the germinal matrix is a highly cellular and highly vascularized region in the brain from which cells migrate out during brain development. The germinal matrix is the source of both neurons and glial cells and is most active between 8 and 28 weeks gestation...
  
  , an embryonic brain tissue
- Matrix, another term for a bacterial growth medium
  Growth medium
  A growth medium or culture medium is a liquid or gel designed to support the growth of microorganisms or cells, or small plants like the moss Physcomitrella patens.There are different types of media for growing different types of cells....
Matrix (archeology)
Matrix (archeology)
In archaeology, the matrix commonly refers to the Harris matrix, a method for recording excavations.It can also mean the soil or sediment matrix surrounding and including the artifacts, features, and other materials at an archaeological site....

, the soil or sediment surrounding a dig site
- Harris matrix
  Harris matrix
  The Harris matrix is a tool used to depict the temporal succession of archaeological contexts and thus the sequence of deposition on a 'dry land' archaeological site. The matrix reflects the relative position and stratigraphic contacts of observable stratigraphic units, or contexts. The Matrix was...
  
  , an archaeological tool used to describe sediment deposition over time
Matrix (chemical analysis)
Matrix (chemical analysis)
In chemical analysis, matrix refers to the components of a sample other than the analyte. The matrix can have a considerable effect on the way the analysis is conducted and the quality of the results obtained; such effects are called matrix effects. For example, the ionic strength of the solution...

, the discarded portion of a sample used for chemical analysis
Matrix (geology)
Matrix (geology)
The matrix or groundmass of rock is the finer grained mass of material in which larger grains, crystals or clasts are embedded.The matrix of an igneous rock consists of finer grained, often microscopic, crystals in which larger crystals are embedded. This porphyritic texture is indicative of...

, the fine grains between larger grains in igneous or sedimentary rocks, or the rock material in which a fossil, gem etc.