This model fitted the Japanese and International Radiation Study of Cervical Cancer Patients leukaemia datasets significantly better, albeit with biologically implausible parameters (the number of initiated cells at birth is negative), than a model which assumed just a single pathway [ 128].
PUFA-CoAs seem to be unique in their ability to inhibit HMGCR, in that fully saturated PA-CoA had physiologically implausible kinetic parameters.
However, as Hornstein et al. (2011) point out, unless some parameters assume implausible values, calibrated standard search models explain only a very small portion of observed wage dispersion.
The new decision support component has also an impact on data quality, because when the list of similar cases is displayed it becomes evident, which parameters are implausible or missing.
Thus, a model constrained on clinical data is critical, and this may help to (i) reject measured values as being physiologically implausible; (ii) allow some uncertain parameters to be estimated through modeling, and (iii) identify highly sensitive parameters or species that are rate‐controlling, because these parameters or species will serve as key elements for the subsequent prediction.
This task is generally considered one that requires biologically implausible precise calibration of multiple parameters [9, 10] and is not well understood (though various solutions to the fine tuning problem have been proposed in [11 14]).
Elimination of inadmissible parameters: With ML estimation it often happens that parameters are estimated with implausible values, for example, negative residual variances or correlations larger than 1.
To avoid biologically implausible dose response curve shapes, the shape parameter, K, was not allowed to be < 1.0 (Crump 2002a) and, for computational reasons, was not allowed to exceed 10.
In fact, only implausible distributions of inter-individual variation in parameters governing individual sigmoidal response could ever result in a low dose linear dose response.
The concentrated likelihood function is approximately monotonic, resulting in maximum likelihood estimates which are close to the boundary of the parameter space, ρ = 1, and the implausible prediction that almost all those who decline to test are HIV negative.
