Why no hair ?

Hello.

When I press bake the hair disappear from the head and in render F12. Why?
I have try to free bake before I bake but still no hair.
lock at my blendfile and tell me how to solve this
Thanks in advance.
http://www.pasteall.org/blend/24284


Change back to Object Mode

Thank you Richard.One more question.
From Object Mode I move to Particle Edit and comb the hair but when I move back to Object mode and Render the hair was not combed. Why.
http://www.pasteall.org/blend/24286


If you made changes to the underlying mesh that’s emitting the particles after combing, you changed how those particles are being emitted and effectively destroyed whatever work you already did. Finish editing your mesh before you move on to other dependent steps like hair.

You have a low number of segments per hair, and children with a large kink, the odd thing is that I am not able to reduce the curl strength by amplitude, while radial and wave types seem to work correctly.
The only fix I found is to increase the ‘Flatness’ parameter.
And remember to set the Display ‘steps’ to the actual number of segments for a correct visualization.

paolo

K Horseman and sourvinos, thanks for important help.