Hamm, H. W. [P:(DE-HGF)0] ; Merkel, R. [P:(DE-Juel1)128833] ; Springer, O. [P:(DE-HGF)0] ; Jurkojc, P. [P:(DE-HGF)0] ; Maier, C. [P:(DE-HGF)0] ; Prechtel, K. [P:(DE-HGF)0] ; Smetacek, V. [P:(DE-HGF)0]