Generalized Rates of Transfer in Open Systems of Pools in the Steady State

Abstract

Previous analyses of tracer experiments, based on models consisting of a discrete number of pools, provided formulae to calculate rates of transfer of material between 2 directly communicating pools. The validity of the calculation of these and of other rates from tracer data appeared to depend upon the number and arrangement of the pools in the system. Furthermore, no formulae were available for calculating rates of transfer of material between pools which do not communicate directly. The present analysis, which applies to open systems in the steady state, presents a formal solution for these difficulties by demonstrating that rates of transfer between selected pools in the system (the primary pools) can be calculated from tracer data obtained only from these pools, regardless of the other pools in the system (the secondary pools). Other parameters, such as the fraction of a pool converted to another (the p factor) or the fraction of a pool which derives from material transferred from another (the [DELTA] factor) are meaningfully defined in terms of rates. Expressions are given for their calculation from experimental data.