When the pressure around the chest wall returns to that of the surrounding air, expiration occurs passively owing to the elastic recoil of the lungs and chest wall. However, during the poliomyelitis epidemic mortality decreased from 87% to 40% when INPV was replaced by positive-pressure ventilation.
Part-Time Per-Credit Costs. The per-credit-hour charge for part-time undergraduate students at Wilmington University in 2015 - 2016 was $346. Typically, college classes consist of 3 or 4 credits, bringing the cost per class to $1,038 or $1,384. At many colleges, full-time tuition kicks in at around 12 credit hours.
Graduate and non-degree students are charged for tuition on a per credit hour basis. Washington College of Law students who register for 12 to 17 credit hours are charged for tuition at a flat full-time rate. Washington College of Law students who register for fewer than 12 credit hours are charged tuition per credit hour based on the number of credit hours taken.