Title: QCD Studies in e+e- Annihilation at sqrt(s) from 30 GeV to 189 GeV

 We present results obtained from a study of the structure of hadronic
 events recorded by the L3 detector at various centre-of-mass energies.
 The distributions of event shape variables and the energy dependence of
 their mean values are measured from 30 GeV to 189 GeV  and compared with
 various QCD models. The energy dependence of the moments of event shape
 variables is used to test a power law ansatz for the non-perturbative
 component. We obtain a universal value of the non-perturbative parameter
 $\alpha_{0}$ = 0.537 +- 0.073. From a comparison
 with resummed O(alphaS^{2}) QCD calculations, we determine the
 strong coupling constant at each of the selected energies. The measurements
 demonstrate the running of alphaS as expected in QCD with a value of
 $\as (mZ)$ = 0.1215 +- 0.0012 (exp) +- 0.0061 (th).

Parallel session #PA 2,3
Plenary session #Pl 12,11

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* paper 2xx *
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