Reference change values

An RCV takes into account both analytical and within-individual variations that were discussed above. It is calculated using the following equation 

In practice, a Z-score of 1.96 for a 95% probabifity is used to identify a significant RCV. A Z-score of 2.58 is used for a 99% probability to ensure an even more significant RCV. The 

Although it would be preferable if the range of values in an mdividual when healthy could be used as the reference for the same individual when he or she is ill, this is largely impractical. The less specific reference interval derived from many individuals must be used as a guide to determine whether a specific result is abnormal. The index of individuality (II) allows a comparison of total within-subject (intraindividual) variation to between-subject (inter-individual) variation. It is calculated as the ratio of the total intraindividual variation to interindividual biological variation as 

A low index of individuality indicates that an analyte has marked individuality and a high index indicates that 

TABLE 17-15 Significance of Changes in Serial Results Probability That Changes Between Successive Values Are Significant (%) 

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In healthy individuals and in stable patients, the delta value between any two results should be small. Acceptable delta values may be calculated within a population of healthy individuals and then averaged, with the average used as a guide to determine whether a difference of possible clinical significance had occurred between. serial measurements in patients. An alternative approach is to use the more refined reference change value (RCV), or critical difference, concept. 

The reference state at To and To is arbitrarily selected, and the values assigned to Hq and are also arbitrary In prac tice, only changes in H and S are of interest, and the reference-state values ultimately cancel in their calculation. 

As equation 2.4.8 indicates, the equilibrium constant for a reaction is determined by the temperature and the standard Gibbs free energy change (AG°) for the process. The latter quantity in turn depends on temperature, the definitions of the standard states of the various components, and the stoichiometric coefficients of these species. Consequently, in assigning a numerical value to an equilibrium constant, one must be careful to specify the three parameters mentioned above in order to give meaning to this value. Once one has thus specified the point of reference, this value may be used to calculate the equilibrium composition of the mixture in the manner described in Sections 2.6 to 2.9. 

Entropy, which has the symbol 5, is a thermodynamic function that is a measure of the disorder of a system. Entropy, like enthalpy, is a state function. State functions are those quantities whose changed values are determined by their initial and final values. The quantity of entropy of a system depends on the temperature and pressure of the system. The units of entropy are commonly J K" mole". If 5 has a ° (5°), then it is referred to as standard molar entropy and represents the entropy at 298K and 1 atm of pressure for solutions, it would be at a concentration of 1 molar. The larger the value of the entropy, the greater the disorder of the system. 

We note that should we use the CHLL2 approach to estimate the enthalpies of vaporization, all of the experimentally measured phase change values in Reference 41 are too large. Recall the... 

In Equation (19), the enthalpy and entropy changes refer to values at 1 bar and the volume of fusion is pressure dependent. The main difficulty with the practical application of (19) to partitioning relations is, as discussed earlier, finding appropriate ways of connecting the weight partition coefficient D to its thermodynamic expression K. This requires making assumptions about the relationship between composition and activity of the component REEMgAlSiOg. 

The target cell and the changing cells must be on the active sheet. Your model can involve external references to values in other worksheets or workbooks, however. 

Considering a finite number of threshold values m, a set of contour surfaces G(m) is studied for each molecule combined with a set of reference curvature values b. Therefore, for each pair (m, b) of parameters, the curvature domains Do(m, b), b) and T>2 m, b) are computed and the truncation of contour surfaces G m) is performed by removing all curvature domains of specified type p (in most applications p = 2) from the contour surface, thus obtaining a truncated surface G(m, p) for each m, b) pair. For most small changes of the parameter values, the truncated surfaces remain topologically equivalent, and only a finite number of equivalence classes is obtained for the entire range of m and b values. 

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