Electronic Journal of Differential Equations, Vol. 2003(2003), No. 82, pp. 1-11. Title: Positive solutions of a three-point boundary-value problem on a time scale Author: Eric R. Kaufmann (Univ. of Arkansas at Little Rock, USA) Abstract: Let $\mathbb{T}$ be a time scale such that $0, T \in \mathbb{T}$. We consider the second order dynamic equation on a time scale $$\displaylines{ u^{\Delta\nabla}(t) + a(t)f(u(t)) = 0, \quad t \in (0,T) \cap \mathbb{T},\cr u(0) = 0, \quad \alpha u(\eta) = u(T), }$$ where $\eta \in (0, \rho(T)) \cap \mathbb{T}$, and $0 < \alpha