Irrational susceptibility

In terms of the irrational susceptibility (ir), which is often used in connection with the older esu, emu, and Gaussian unit systems (see section 7.3 below), this equation becomes... 

The effective magnetic moment, can be obtained from the experimentally measured molar magnetic susceptibility, Xm, and is expressed in Bohr magnetons p ) where l B = eh/Attm = 9.27 x 10 JT . Equation 20.12 gives the relationship between and Xml using SI units for the constants, this expression reduces to equation 20.13 in which Xm is in cm moU. In the laboratory, the continued use of Gaussian units in magnetochemistry means that irrational susceptibility is the measured quantity and equation 20.14 is therefore usually applied. ... 

But note in practice the units cm3 mol 1 usually imply that the irrational molar susceptibility... 

When the equations of electromagnetic theory are written in this alternative irrational form, six other new quantities are defined in addition to e0(ir) and fi0iir) namely e(ir), n T D(ir), if(ir), xt iT) (the electric susceptibility), and x(ir) (the magnetic susceptibility). The definitions of other quantities remain unchanged. In each case we denote the new quantities by a superscript (ir) for irrational. The new quantities are defined in terms of the old quantities by the equations... 

The use of antimicrobial agents for relatively trivial infections encourages the selection of resistant organisms. Consequently, in the absence of evidence of a susceptible pathogen, antimicrobial use is irrational and may expose treated horses to unnecessary risks. 

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