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  2. Rarefaction (ecology) - Wikipedia

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

    Rarefaction curves are created by randomly re-sampling the pool of N samples multiple times and then plotting the average number of species found in each sample (1,2, ... N). "Thus rarefaction generates the expected number of species in a small collection of n individuals (or n samples) drawn at random from the large pool of N samples.". [2]

  3. Knudsen number - Wikipedia

    en.wikipedia.org/wiki/Knudsen_number

    The Knudsen number is a dimensionless number defined as =, where = mean free path [L 1], = representative physical length scale [L 1].. The representative length scale considered, , may correspond to various physical traits of a system, but most commonly relates to a gap length over which thermal transport or mass transport occurs through a gas phase.

  4. Globally Harmonized System of Classification and Labelling of ...

    en.wikipedia.org/wiki/Globally_Harmonized_System...

    The pictogram for harmful substances of the Globally Harmonized System of Classification and Labelling of Chemicals.. The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) is an internationally agreed-upon standard managed by the United Nations that was set up to replace the assortment of hazardous material classification and labelling schemes previously used around ...

  5. Rarefaction - Wikipedia

    en.wikipedia.org/wiki/Rarefaction

    Rarefaction is the reduction of an item's density, the opposite of compression. [1] Like compression, which can travel in waves ( sound waves , for instance), rarefaction waves also exist in nature. A common rarefaction wave is the area of low relative pressure following a shock wave (see picture).

  6. Extinction event - Wikipedia

    en.wikipedia.org/wiki/Extinction_event

    In a landmark paper published in 1982, Jack Sepkoski and David M. Raup identified five particular geological intervals with excessive diversity loss. [2] They were originally identified as outliers on a general trend of decreasing extinction rates during the Phanerozoic, [3] but as more stringent statistical tests have been applied to the accumulating data, it has been established that in the ...

  7. Restriction site associated DNA markers - Wikipedia

    en.wikipedia.org/wiki/Restriction_site...

    Restriction site associated DNA (RAD) markers are a type of genetic marker which are useful for association mapping, QTL-mapping, population genetics, ecological genetics and evolutionary genetics. The use of RAD markers for genetic mapping is often called RAD mapping.

  8. Nominal number - Wikipedia

    en.wikipedia.org/wiki/Nominal_number

    Labelling referees Smith and Kumar as referees "1" and "2" is a use of nominal numbers. Any set of numbers (a subset of the natural numbers) will be consistent labels as long as a distinct number is uniquely used for each distinct term which needs to be labelled. Nonetheless, sequences of integers may naturally be used as the simplest way to ...

  9. Hazardous Materials Identification System - Wikipedia

    en.wikipedia.org/wiki/Hazardous_Materials...

    The second edition was released in 1986, HMIS II, which introduced letter codes for identifying personal protective equipment to be used, and the 'asterisk' to the Health bar, to identify when a substance poses a long term health hazard, such as carcinogens. This would be placed in the same box as the health number. [3] [5] [6]