background:   objective: to determine whether different diagnostic criteria of gestational diabetes mellitus (gdm) are suitable for iranian population.   materials and methods: prospective study was performed on 617 pregnant women. 1804 subjects referred for 50 g glucose challenge test (gct) between 24th and 28 th weeks of gestation. 617 women with abnormal gct (blood glucose ≥130 mg/dl) underw...

Consider the first-order linear delay differential equation x′(t) + p(t)x(τ(t)) = 0, t ≥ t0, and the second-order linear delay equation x′′(t) + p(t)x(τ(t)) = 0, t ≥ t0, where p and τ are continuous functions on [t0,∞), p(t) > 0, τ(t) is nondecreasing, τ(t) ≤ t for t ≥ t0 and limt→∞ τ(t) = ∞. Several oscillation criteria are presented for the first-order equation when

We reconsider necessary and suffcient conditions for dynamic inefficiency given in Zilcha (1990, 1991) and a critique by Rangazas and Russell (2005). First, we show that the characterization given in Zilcha (1990) for nonstationary economies is correct and complete Zilcha's proof. Second, using this insight, we complement Rangazas and Russell (2005)'s discussion of the counterexamples to Zilcha...