FUNCTION DUSTEM_CUT_OFF, x, par; generates the large size cut-off ; from Weingartner & Draine 2001; x : grain size ; par(0) : threshold for cut-off (At); par(1) : shape As(roughly the size where cut_off=0.5) y = 0.d0*x + 1.d0 ix = WHERE( x GT par(0), cnt )if CNT GT 0 then begin y(ix)= exp( -( (x(ix)-par(0)) / par(1))^3. ) endif else begin print,'(W) DUSTEM_CUT_OFF: no size larger than At found' endelseRETURN, yEND