Where, as above, C is annuity payment, PV is principal, n is number of payments, starting at end of first period, and i is interest rate per period. Equivalently C is the periodic loan repayment for a loan of PV extending over n periods at interest rate, i.
Refractory epilepsy is a seizure disorder that resists drug treatment. There is some debate among clinicians and researchers about how to define refractory epilepsy. As a result, this term is used in a variety of ways, and when a patient's epilepsy is described as refractory, resistant, or nonresponsive, it can be advisable to ask for more detail about what the diagnosis means.
Report Abuse. Refractory material is one that retains and maintains its strength at high temperatures without softening or deformation in shape. The most important chemical composition of refractory is the oxides of aluminum, silicon and magnesium. Another oxide usually used in refractory is the oxide of calcium.eport Abuse. Refractory material is one that retains and maintains its strength at high temperatures without softening or deformation in shape. The most important chemical composition of refractory is the oxides of aluminum, silicon and magnesium. Another oxide usually used in refractory is the oxide of calcium.