Astrophysical fluid dynamics, E.A. Spiegel; hydrodynamic turbulence, M. Lesieur; generic instabilities and non linear dynamics, O. Thual; magnetohydrodynamic turbulence, A. Pouquet; dynamo theory, P.H. Roberts; thermal convection and penetration, J. Toomre; linear adiabatic stellar pulsation, D.O. Gough; instabilities and turbulence in rotating stars, J.-P. Zahn.