../ 13309-t.tex 28-Aug-2004 10:04 270201 13309-t.zip 28-Aug-2004 12:04 88788 fig1.eps 28-Aug-2004 10:04 5955 fig2.eps 28-Aug-2004 10:04 5726 fig3.eps 28-Aug-2004 10:04 5622