diff options
Diffstat (limited to 'vignettes/FOCUS_Z.Rnw')
| -rw-r--r-- | vignettes/FOCUS_Z.Rnw | 57 |
1 files changed, 44 insertions, 13 deletions
diff --git a/vignettes/FOCUS_Z.Rnw b/vignettes/FOCUS_Z.Rnw index 44cfa46..694c5ee 100644 --- a/vignettes/FOCUS_Z.Rnw +++ b/vignettes/FOCUS_Z.Rnw @@ -85,7 +85,8 @@ is negligible. Accordingly, the exact magnitude of the fitted parameter This suggests, in agreement with the analysis in the FOCUS kinetics report, to simplify the model by removing the pathway to sink. -A similar result can be obtained when formation fractions are used in the model formulation: +A similar result can be obtained when formation fractions are used in the model +formulation: <<FOCUS_2006_Z_fits_2, echo=TRUE, fig.height=4>>= Z.2a.ff <- mkinmod(Z0 = list(type = "SFO", to = "Z1"), @@ -97,13 +98,13 @@ plot(m.Z.2a.ff) summary(m.Z.2a.ff, data = FALSE) @ -Here, the ilr transformed formation fraction fitted in the model takes a very large value, -and the backtransformed formation fraction from parent Z to Z1 is practically unity. Again, -the covariance matrix is not returned as the model is overparameterised. +Here, the ilr transformed formation fraction fitted in the model takes a very +large value, and the backtransformed formation fraction from parent Z to Z1 is +practically unity. Again, the covariance matrix is not returned as the model is +overparameterised. The simplified model is obtained by setting the list component \texttt{sink} to -\texttt{FALSE}. This model definition is not supported when formation fractions -are used. +\texttt{FALSE}. <<FOCUS_2006_Z_fits_3, echo=TRUE, fig.height=4>>= Z.3 <- mkinmod(Z0 = list(type = "SFO", to = "Z1", sink = FALSE), @@ -113,6 +114,19 @@ plot(m.Z.3) summary(m.Z.3, data = FALSE) @ +This model definition is not supported when formation fractions +are used, but the formation fraction can be fixed to unity. + +<<FOCUS_2006_Z_fits_3.ff, echo=TRUE, fig.height=4>>= +Z.3.ff <- mkinmod(Z0 = list(type = "SFO", to = "Z1"), + Z1 = list(type = "SFO"), use_of_ff = "max") +m.Z.3.ff <- mkinfit(Z.3.ff, FOCUS_2006_Z_mkin, + parms.ini = c(f_Z0_to_Z1 = 1), + fixed_parms = "f_Z0_to_Z1", + quiet = TRUE) +summary(m.Z.3.ff, data = FALSE) +@ + \section{Including metabolites Z2 and Z3} As suggested in the FOCUS report, the pathway to sink was removed for metabolite Z1 as @@ -196,7 +210,7 @@ for the same reasons as in the original analysis. <<FOCUS_2006_Z_fits_9, echo=TRUE, fig.height=4>>= Z.mkin.3 <- mkinmod(Z0 = list(type = "SFORB", to = "Z1", sink = FALSE), - Z1 = list(type = "SFO", to = "Z2"), + Z1 = list(type = "SFO", to = "Z2", sink = FALSE), Z2 = list(type = "SFO")) m.Z.mkin.3 <- mkinfit(Z.mkin.3, FOCUS_2006_Z_mkin, quiet = TRUE) plot(m.Z.mkin.3) @@ -206,8 +220,8 @@ summary(m.Z.mkin.3, data = FALSE) This results in a much better representation of the behaviour of the parent compound Z0. -Finally, Z3 is added as well. This model appears overparameterised (no -covariance matrix returned) if the sink for Z1 is left in the model. +Finally, Z3 is added as well. These models appear overparameterised (no +covariance matrix returned) if the sink for Z1 is left in the models. <<FOCUS_2006_Z_fits_10, echo=TRUE, fig.height=4>>= Z.mkin.4 <- mkinmod(Z0 = list(type = "SFORB", to = "Z1", sink = FALSE), @@ -234,12 +248,29 @@ m.Z.mkin.5 <- mkinfit(Z.mkin.5, FOCUS_2006_Z_mkin, parms.ini = m.Z.mkin.4$bparms.ode[1:5], quiet = TRUE) plot(m.Z.mkin.5) -summary(m.Z.mkin.5, data = FALSE) +summary(m.Z.mkin.5, data = FALSE)$bpar +@ + +The summary view of the backtransformed parameters shows that we get no +confidence intervals due to overparameterisation. As the optimized +\texttt{k\_Z3\_bound\_free} is excessively small, it is reasonable to fix it to +zero. +<<FOCUS_2006_Z_fits_11a, echo=TRUE, fig.height=4>>= +m.Z.mkin.5a <- mkinfit(Z.mkin.5, FOCUS_2006_Z_mkin, + parms.ini = c(m.Z.mkin.4$bparms.ode[1:5], + k_Z3_bound_free = 0), + fixed_parms = "k_Z3_bound_free", + quiet = TRUE) +summary(m.Z.mkin.5a, data = FALSE)$bpar +@ + +A graphical representation of the confidence intervals can finally be obtained. +<<FOCUS_2006_Z_fits_11b, echo=TRUE, fig.height=4>>= +mkinparplot(m.Z.mkin.5a) @ -Looking at the confidence intervals of the SFORB model parameters of Z3, it is -clear that nothing can be said about the degradation rate of Z3 towards the end -of the experiment. However, this appears to be a feature of the data. +It is clear that nothing can be said about the degradation rate of Z3 towards +the end of the experiment. However, this appears to be a feature of the data. <<FOCUS_2006_Z_residuals_11>>= par(mfrow = c(2, 2)) |