When using a PBO as target for glReadPixels you have to specify a byte offset into the buffer ( 0 I suppose) instead of (uchar*)cvimg->imageData as target address. It is similar to using a buffer offset in glVertexPointer when using VBOs.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.