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One part per hundred thousand, per cent mille (pcm) or milli-percent denotes one part per 100,000 (10 5) parts, and a value of 10 −5. It is commonly used in epidemiology for mortality, crime and disease prevalence rates, and nuclear reactor engineering as a unit of reactivity.
The word promille is the cognate in Dutch, German, Finnish and Swedish, and is sometimes seen as a loanword in English with the same meaning as per mille. [7] [4] The symbol is included in the General Punctuation block of Unicode at U+2030 ‰ PER MILLE SIGN. [5] There is also an Arabic-Indic per mille sign at U+0609 ؉ ARABIC-INDIC PER MILLE SIGN.
Foraminifera samples. In geochemistry, paleoclimatology, and paleoceanography δ 13 C (pronounced "delta thirteen c") is an isotopic signature, a measure of the ratio of the two stable isotopes of carbon— 13 C and 12 C—reported in parts per thousand (per mil, ‰). [1]
Hence deviations from natural abundance on Earth are often measured in parts per thousand (per mille or ‰) because they are less than one percent (%). An exception to this lies with the presolar grains found in primitive meteorites. These small grains condensed in the outflows of evolved ("dying") stars and escaped the mixing and ...
It is an extension of the older karat system of denoting the purity of gold by fractions of 24, such as "18 karat" for an alloy with 75% (18 parts per 24) pure gold by mass. The millesimal fineness is usually rounded to a three figure number, particularly where used as a hallmark , and the fineness may vary slightly from the traditional ...
Both have the form ‰ (‰ = permil or parts per thousand) where s and a are the relative abundances of 15 N in respectively the sample and the atmosphere. The difference is whether the relative abundance is with respect to all the nitrogen, i.e. 14 N plus 15 N, or just to 14 N.
A related concept is one part per ten thousand, 1 / 10,000 .The same unit is also (rarely) called a permyriad, literally meaning "for (every) myriad (ten thousand)". [4] [5] If used interchangeably with basis point, the permyriad is potentially confusing because an increase of one basis point to a 10 basis point value is generally understood to mean an increase to 11 basis points; not ...
Isotope fractionation occurs during a phase transition, when the ratio of light to heavy isotopes in the involved molecules changes.When water vapor condenses (an equilibrium fractionation), the heavier water isotopes (18 O and 2 H) become enriched in the liquid phase while the lighter isotopes (16 O and 1 H) tend toward the vapor phase.