The SAS System                                1
                                                   09:26 Thursday, April 7, 2011

                               The NLIN Procedure
                           Dependent Variable uptake
                              Method: Gauss-Newton

                                Iterative Phase
                                                            Sum of
              Iter           a           k          x0     Squares

                 0     20.0000     -0.0100      1.0000    2.286E12
                 1     23.8891     -0.0100       120.6    2.991E11
                 2     23.8895     -0.0100       221.0    4.045E10
                 3     23.8909     -0.0100       322.0    5.4609E9
                 4     23.8945     -0.0101       424.2    7.3428E8
                 5     23.9044     -0.0102       529.4    97569523
                 6     23.9311     -0.0104       641.0    12501946
                 7     24.0021     -0.0113       766.6     1409068
                 8     24.1849     -0.0144       924.9     88247.2
                 9     24.5985     -0.0522      1200.3     10281.4
                10     26.1514     -0.0522      201669      9801.7
                11     27.2131     -0.0522      201669      9707.0


        NOTE: Convergence criterion met but a note in the log indicates 
        a possible problem with the model.                              


                               Estimation Summary

                      Method                  Gauss-Newton
                      Iterations                        11
                      R                                  0
                      PPC                                0
                      RPC(a)                      0.040598
                      Object                       0.00966
                      Objective                   9706.976
                      Observations Read                 84
                      Observations Used                 84
                      Observations Missing               0


                                     Sum of        Mean               Approx
   Source                    DF     Squares      Square    F Value    Pr > F

   Model                      0    1.46E-11           .        .       .    
   Error                     83      9707.0       117.0                     
   Corrected Total           83      9707.0                                 

                  NOTE: The (approximate) Hessian is singular.
                                 The SAS System                                2
                                                   09:26 Thursday, April 7, 2011

                               The NLIN Procedure

                                        Approx      Approximate 95% Confidence
          Parameter      Estimate    Std Error                Limits

          a               27.2131       1.1799     24.8662     29.5600
          k               -0.0522            .           .           .
          x0               201669            .           .           .


                         Approximate Correlation Matrix
                                a               k              x0

               a        1.0000000               .               .
               k         .                      .               .
               x0        .                      .               .