Research Paper Volume 8, Issue 11 pp 3045—3064

Figure 6. Time-evolution of mortality dynamics in the mathematical model of a heterogeneous population. The model of a heterogeneous population composed of four subpopulations is modified to contain time-dependent parameters and is used to fit period Swedish death rates for ages 0 to 100 and for the entire 20^th century period (1900-2000). The resulting fitted surface of the modified model to the age- and time-related Swedish data is shown in panel (D). The initial mortalities and the mortality coefficients of subpopulations are assumed to change linearly over time (fits are shown in panels (A) and (B) respectively) while their initial fractions change exponentially (shown in panel (C)). Note that the plot in panel A is shown on a semi-logarithmic scale.