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.
1 Their costs are currently $715 per credit for a 64 credit program, which translates into $47,760 in tuition costs that will reach $50,000 with the addition of technology fees and other ancillary charges.2  Fordham University also charges a flat rate per credit for graduate studies. University of California/Berkeley was charging 5,616.25 per semester for state residents, a cost that included student health insurance. 2  That would result in a total tuition cost of $22,465 plus the student fees, which at Berkeley can be another few hundred dollars per semester.