A hypothesis is proposed that the oscillations in blood cell numbers are the result of suppressed productivity of the bone marrow and its ability to satisfy both the demands of the erythroid and myeloid cell lines. The hypothesis is used as the basis for a mathematical model which describes the oscillations in all subpopulations of these cell lines. The relationship between the period and amplitude of the oscillations and the extent of suppression of the bone marrow productivity have been explored.
Abstract. Based on data from the literature, the major regulatory features were established for the erythroid population regenerating after perturbation. A mathematical model is proposed which takes into account: (1) the increase in the proliferating CFU‐S due to depopulation of CFU‐S and BFU‐E/8 pools due to increased migration caused by erythropoietin; (2) regeneration of erythroid precursors due to short‐range factors and (3) gradual reduction in the short‐range effects and increase in the humoral influence on BFU‐E/8, BFU‐E/3 and CFU‐E together with short‐range suppression of progenitor differentiation and acceleration of maturation in all subpopulations due to humoral factors. The kinetics of subpopulations as a function of feedback and maturation rate are analysed. The dependence of erythrocyte production on erythrocyte depletion in the blood and on the feedback coefficient is defined.
It is necessary to know exactly the positions and strengths of absorption bands in many applications of spectral analysis. The maxima in an over-all band are usually displaced relative to those of the components, and the shifts are dependent on the strengths and half-widths of adjacent components.Often, maxima vanish altogether.We assume that the absorption curve is closely described by(1) i=l The parameters I i, at, and b i have to be determined for each peak during resolution into components. The parameters of an isolated Gaussian peak have the following relation to lnyi(x):In 9i (x) = In I i --aib ~ + 2alblx --aix 2.(2)We need only three points in each range in order to determine z0i = lnli-aib [, zl[ = 2aib i, zfi = -ai, but it is better to use statistical methods, in particular least squares [1, 2] by minimizing X2
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