How do impulsive differential equations work? Can you provide an example? I have heard of impulsive differential equations being used in some epidemiological models of infectious disease. I haven't heard of them before in my math education, and I was wondering how they might work. I presume there is some mechanism to introduce a step-wise/impulse discontinuity, but I'm not sure what a simple model might look light, or how it behaves. Any help would be appreciated.

As far as I know, it can be related to differential equations on Time Scales
(those are some closed subsets of the real line and it is defined axiomatically by Stefan Hilger)
http://www.answers.com/Q/What_is_impulsive_differential_equation
But when Time scale T, as a domain of the solution of the differential equation, comprises only scattered points it may becomes more simpler than the case at which T contains both scattered and dense points.
