An improved regression method for the evaluation of standard free energies of formation (ΔG°f) of clay minerals is here proposed in an attempt to remove some of the limitations of the earlier method (Chen, 1975). Particularly, this method suggests a procedure for the assignment of rankings for Σ ΔG°f, i values. Moreover, an iterative least-squares fitting technique is applied to solve the exponential equation to obtain the estimated ΔG°f. The estimated ΔG°f data for the various standard clay minerals are derived and compared with data available in the literature; in general, there is good agreement between the values. It is also shown how the regression method can be extended to clay minerals of variable composition. The ΔG°f's for several such minerals have been evaluated; a large number of combination equations required for such computations have been listed, so that for other similar minerals the process of evaluation of ΔG°f is greatly simplified.

This study was designed to examine the dyslexic subtypes in a transparent orthography (i.e., Spanish language). The subtyping procedure used comparison with chronological-age-matched and reading-level controls on reaction times (RTs) to high frequency words and to pseudowords. Using regression-based procedures, the authors identified 20 phonological and 48 surface dyslexics from a sample of 89 dyslexic third-grade children by comparing them to chronological-age-matched controls on RTs to high frequency and pseudoword reading. However, when the dyslexic subtypes were defined by reference to reading-level controls, the same 20 phonological dyslexics were defined, but only 19 surface dyslexics were identified. Nevertheless, the results of the phonological awareness tasks and error analysis do not validate the division of the dyslexic sample into these subgroups.

Electrooculogram (EOG) correction is used to remove eye-movement-related contamination from electroencephalograms (EEG). Correction is reliant on the regression procedure, although when multiple EOG channels are used in the correction, the appropriate type of regression to use is not known. In the present study, we aimed to resolve this matter. Computer simulations were used to compare the simultaneous, multiple-stage, and single-channel regression methods of correction. EOG propagation was modeled on prior findings, under conditions of varying vertical and horizontal EOG (VEOG/HEOG) correlation. The dependent variable was the correlation between the uncontaminated and the corrected EEG. The simultaneous regression procedure gave the best correction, with its advantage increasing as a function of VEOG/HEOG correlation. It is recommended that the simultaneous regression procedure be used for EOG correction of the EEG.