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  2. Normal mode - Wikipedia

    en.wikipedia.org/wiki/Normal_mode

    This space-dependence is called a normal mode. Usually, for problems with continuous dependence on (x, y, z) there is no single or finite number of normal modes, but there are infinitely many normal modes. If the problem is bounded (i.e. it is defined on a finite section of space) there are countably many normal modes (usually numbered n = 1, 2 ...

  3. Molecular vibration - Wikipedia

    en.wikipedia.org/wiki/Molecular_vibration

    A molecular vibration is a periodic motion of the atoms of a molecule relative to each other, such that the center of mass of the molecule remains unchanged. The typical vibrational frequencies range from less than 10 13 Hz to approximately 10 14 Hz, corresponding to wavenumbers of approximately 300 to 3000 cm −1 and wavelengths of approximately 30 to 3 μm.

  4. Taxonomy - Wikipedia

    en.wikipedia.org/wiki/Taxonomy

    Pragmatic classification (and functional [40] and teleological classification) is the classification of items which emphasis the goals, purposes, consequences, [41] interests, values and politics of classification. It is, for example, classifying animals into wild animals, pests, domesticated animals and pets.

  5. Class (biology) - Wikipedia

    en.wikipedia.org/wiki/Class_(biology)

    The hierarchy of biological classification's eight major taxonomic ranks. A phylum contains one or more classes. Intermediate minor rankings are not shown. In biological classification, class (Latin: classis) is a taxonomic rank, as well as a taxonomic unit, a taxon, in that rank. It is a group of related taxonomic orders.

  6. Taxonomy (biology) - Wikipedia

    en.wikipedia.org/wiki/Taxonomy_(biology)

    His 2004 classification treated the archaeobacteria as part of a subkingdom of the kingdom Bacteria, i.e., he rejected the three-domain system entirely. [72] Stefan Luketa in 2012 proposed a five "dominion" system, adding Prionobiota (acellular and without nucleic acid) and Virusobiota (acellular but with nucleic acid) to the traditional three ...

  7. Taxonomic rank - Wikipedia

    en.wikipedia.org/wiki/Taxonomic_rank

    Cladistics is a method of classification of life forms according to the proportion of characteristics that they have in common (called synapomorphies). It is assumed that the higher the proportion of characteristics that two organisms share, the more recently they both came from a common ancestor.

  8. Level of measurement - Wikipedia

    en.wikipedia.org/wiki/Level_of_measurement

    Level of measurement or scale of measure is a classification that describes the nature of information within the values assigned to variables. [1] Psychologist Stanley Smith Stevens developed the best-known classification with four levels, or scales, of measurement: nominal, ordinal, interval, and ratio.

  9. Statistical classification - Wikipedia

    en.wikipedia.org/wiki/Statistical_classification

    [3] [4] Later work for the multivariate normal distribution allowed the classifier to be nonlinear: [5] several classification rules can be derived based on different adjustments of the Mahalanobis distance, with a new observation being assigned to the group whose centre has the lowest adjusted distance from the observation.