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Chapter 2: Recommended abbreviations


2.1 Background


Contributors: All participants

2.1 Background

Early users of the doubly-labelled water method have tended to adopt their own variants and extensions of Lifson's initial notation. This causes unnecessary difficulty when the reader has to cross-refer to the author's particular usage, and in certain cases can lead to ambiguity. The working group therefore agreed to adopt the following notation for use in this and subsequent publications relating to human applications of doubly-labelled water. Others entering the field for the first time are strongly urged to employ the same symbols which will be referred to as 'IDECG Notation'.

Table 2.1. IDECG Notation

Variable

Notation

Isotopes

Unspecified isotopes of H or O

*H or *O

Oxygen

O or 16O and 18O

Hydrogen (protium)

H or 1H

Deuterium

D or 2H

Tritium

T or 3H

Dosing variables

Dose administered to subject

A (AD and AO)

Dose diluted for analysis

a (aD and aO)

Amount of water used for dilution

W

Pool sizes and rate constants

Pool size

N (ND and NO)

Rate constant

k (kD and kO)

Production rate

r

Uncorrected production rate

r'

Fractionation factors

2H2O vapour/liquid

f1

H218O vapour/liquid

f2

C18O2/H218O

f3

Mass spectrometric variables

Isotopic enrichment (relative to a standard)

d

Fractional abundance (concentration)

C

Atom percent excess

APE

Parts per million

ppm

Working standard

ws

Vienna-Standard Mean Ocean Water

V-SMOW or SMOW

Standard Light Antarctic Precipitation

SLAP

 


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