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  2. Rarefaction (ecology) - Wikipedia

    en.wikipedia.org/wiki/Rarefaction_(ecology)

    The technique of rarefaction was developed in 1968 by Howard Sanders in a biodiversity assay of marine benthic ecosystems, as he sought a model for diversity that would allow him to compare species richness data among sets with different sample sizes; he developed rarefaction curves as a method to compare the shape of a curve rather than absolute numbers of species.

  3. Rarefaction - Wikipedia

    en.wikipedia.org/wiki/Rarefaction

    A common rarefaction wave is the area of low relative pressure following a shock wave (see picture). Rarefaction waves expand with time (much like sea waves spread out as they reach a beach); in most cases rarefaction waves keep the same overall profile ('shape') at all times throughout the wave's movement: it is a self-similar expansion. Each ...

  4. Method of characteristics - Wikipedia

    en.wikipedia.org/wiki/Method_of_characteristics

    Characteristics may fail to cover part of the domain of the PDE. This is called a rarefaction, and indicates the solution typically exists only in a weak, i.e. integral equation, sense. The direction of the characteristic lines indicates the flow of values through the solution, as the example above demonstrates.

  5. Qualitative variation - Wikipedia

    en.wikipedia.org/wiki/Qualitative_variation

    In this sample some groups may be necessarily absent from this subsample. Let be the number of groups still present in the subsample of n items. is less than K the number of categories whenever at least one group is missing from this subsample. The rarefaction curve, is defined as:

  6. Dispersion relation - Wikipedia

    en.wikipedia.org/wiki/Dispersion_relation

    Isaac Newton studied refraction in prisms but failed to recognize the material dependence of the dispersion relation, dismissing the work of another researcher whose measurement of a prism's dispersion did not match Newton's own. [6] Dispersion of waves on water was studied by Pierre-Simon Laplace in 1776. [7]

  7. Brachistochrone curve - Wikipedia

    en.wikipedia.org/wiki/Brachistochrone_curve

    The curve of fastest descent is not a straight or polygonal line (blue) but a cycloid (red).. In physics and mathematics, a brachistochrone curve (from Ancient Greek βράχιστος χρόνος (brákhistos khrónos) 'shortest time'), [1] or curve of fastest descent, is the one lying on the plane between a point A and a lower point B, where B is not directly below A, on which a bead slides ...

  8. Surface plasmon resonance - Wikipedia

    en.wikipedia.org/wiki/Surface_plasmon_resonance

    SPR curves measured during the adsorption of a polyelectrolyte and then a clay mineral self-assembled film onto a thin (ca. 38 nanometers) gold sensor. One of the first common applications of surface plasmon resonance spectroscopy was the measurement of the thickness (and refractive index) of adsorbed self-assembled nanofilms on gold substrates.

  9. Refraction - Wikipedia

    en.wikipedia.org/wiki/Refraction

    In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. [1] Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. How much a wave ...