Comparability studies difference criteria

Confining their study to monofunctional molecules, Roberts et al. [38] compared seven different models for predicting human stratum corneum permeability coefficients. The performance of the models was assessed by the adjusted coefficient of determination r2dj and the Akaike Information Criterion (AIC) [39], Both r2dj and AIC allow for comparing models with different numbers of variables (degrees of freedom). Exclusion of polyfunctional molecules led to a comparatively small set of only 24 molecules. The previously reported... 

In this part of the study, optimisation of the production is carried out according to a global approach. The reaction step and the successive distillation step are considered simultaneously in the evaluation of the optimal operating conditions. In order to compare these results with the classical approach ones an operating time criterion has been chosen. Thus, the optimisation problem lies in the minimisation of the operating time required for the propylene glycol synthesis. According to the previous optimisations, two kinds of production have been studied a production with yield and purity constraints and a production with an additional by-products constraint. In order to compare the different approaches, the same constraints have been adopted. 

The standard state chosen for the calculation of controls its magnitude and even its sign. The standard state is established when the concentration scale is selected. For most solution kinetic work the molar concentration scale is used, so A values reported by different workers are usually comparable. Nevertheless, an important chemical question is implied Because the sign of AS may depend upon the concentration scale used for the evaluation of the rate constant, which concentration scale should be used when A is to serve as a mechanistic criterion The same question appears in studies of equilibria. The answer (if there is a single answer) is not known, though some analyses of the problem have been made. Further discussion of this issue is given in Section 6.1. 

There are many different zeolite structures but only a few have been studied extensively for membrane applications. Table 10.1 lists some of these structures and their basic properties. One of the most critical selection criterion when choosing a zeolite for a particular application is the pore size exhibited by the material. Figure 10.1 compares the effective pore size of the different zeolitic materials with various molecule kinetic diameters. Because the pores of zeolites are not perfectly circular each zeolite type is represented by a shaded area that indicates the range of molecules that may stiU enter the pore network, even if they diffuse with difficulty. By far the most common membrane material studied is MFI-type zeolite (ZSM-5, Al-free siUcahte-l) due to ease of preparation, control of microstructure and versatility of applications [7]. 

If mild discontinuation symptoms can be mistaken for relapse, it would be predicted that studies that used hospitalisation as the relapse criterion would find smaller differences between drug treatment and placebo than other studies. The only study included in the Gilbert et al. (1995) meta-analysis to define relapse exclusively as hospitalisation found a difference of only 17% in relapse rates between people who continued to receive drugs and those withdrawn to placebo after two years (Carpenter, Jr. et al. 1990). This compares with an average difference in relapse rates of 37% at 10 months for all studies included in the analysis. 

Third, establish the relative significance (weight) of each criterion. This usually is accomplished via a set of pairwise comparisons among the different criteria. In each pairwise comparison, two criteria on the same hierarchical level are directly compared. The decision maker (in this case, the study team) establishes the importance of one criteria relative to the other. All unique pairs of criteria at each level of the hierarchy are compared via such pairwise comparisons until all possible combinations have been compared. AHP then translates the pairwise comparison results into a relative weight for each criterion. 

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