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.
In common sense, refractory period is the characteristic recovery time, a period of time that is associated with the motion of the image point on the left branch of the isocline u Ë = 0 {\displaystyle {\dot {u}}=0} (for more details, see also Reaction-diffusion and Parabolic partial differential equation).