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.
Future Part-Time Per-Credit Costs. With an average annual increase in per-credit charges of 5.0% over the past five years, the per credit cost for the 2014 - 2015 year is expected to be $843 and may reach $975 per credit by the 2017 - 2018 school year.