Erythrocyte senescence (cohort kinetics): f(a) = 1/T_life on [0, T_life]; ⟨a⟩ = T_life/2

Erythrocyte senescence cohort kinetics — the canonical steady-state age-distribution framework for red blood cells. Physical setup: under homeostasis, bone-marrow erythropoiesis produces RBCs at a (possibly time-varying) rate λ(t); each…