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In ecology, rarefaction is a technique to assess species richness from the results of sampling. Rarefaction allows the calculation of species richness for a given number of individual samples, based on the construction of so-called rarefaction curves. This curve is a plot of the number of species as a function of the number of samples.
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).
DNA barcoding is a method of species identification using a short section of DNA from a specific gene or genes. The premise of DNA barcoding is that by comparison with a reference library of such DNA sections (also called "sequences"), an individual sequence can be used to uniquely identify an organism to species, just as a supermarket scanner uses the familiar black stripes of the UPC barcode ...
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 ...
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 ...
The purpose of the main number is to assign a filing number to the stamper, and to ensure each side receives the proper label, by visually comparing the number on the label to the inscribed number. The most important part of the extra information is usually the cut number, which is a suffix to the main number. For example, matrix number 12345 ...
Catalog number 811 767-1, used by RSO Records, next to the center hole on a vinyl LP record. A catalog number is an identification number assigned to a music release by a record label.
It helps to identify products and services that have a reduced environmental impact throughout their life cycle. Recognized throughout Europe, it is a voluntary label promoting environmental excellence which can be trusted. It is the only pan-European Type I official ecolabel.