Sigma-minus values

Fathead minnow, Pimephales promelas, acute toxicity, nitrobenzenes, chloroanilines, alkylanilines, OSAR, sigma minus values, anilines, nitroso compounds, tautomerism, Michael acceptors, electrophiles. 

To account for this elfect, a second a value, a—(sigma minus), was assigned to each para substituent. Table 3.1 shows these values for the substituted phenols and Figure 3.4 shows that the resulting relationship is more linear. 

The symbol 2 (sigma) means "the sum of," and n and m are the stoichiometric coefficients of the chemical equation. The first term in Equation 5.31 represents the formation reactions of the products, which are written in the "forward" direction, that is, elements reacting to form products. This term is analogous to Equations 5.27 and 5.28 in the previous example. The second term represents the reverse of the formation reactions of the reactants, as in Equation 5.26, which is why the AHj values have a minus sign in front of them. 

In the context of Eurocode, liquefaction assessments should use the penetration resistance at approximately the mean minus 1.5 sigma as characteristic that is, it is the looser parts of a fill that control the mass behaviour. The characteristic q will also be a profile with depth, not a single value (all else equal, penetration resistance increases with depth because of confining stress). 

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