On Effective Charges, Event shapes and the size of Power Corrections
  We introduce and motivate the method of effective chsrges, and consider how to implement an all-orders resummation of large kinematical logarithms in this formalism. Fits for QCD \Lambda and power corrections are performed for the e+e- event shape observables 1-thrust and heavy jet mass, and somewhat smaller power corrections are found than in the usual approach employing the ``physical scale'' choice. 
C.J. Maxwell