QCD Analyses and Determinations of the Strong                                  
Coupling Strength in e+e-  Annihilations at Energies between 35 and 189 GeV    
  
     We employ data taken by the JADE and OPAL experiments for a               
     QCD study in hadronic e+e- annihilations at c.m. energies ranging         
     from 35 GeV through 189 GeV.  The observables are obtained using          
     the JADE, Durham, Cambridge and cone jet finders, and are compared        
     with the predictions of QCD and Monte Carlo models.  The strong coupling  
     strength is determined at each energy by fits of fixed order and matched  
     NLLA predictions to the data.                                             
     We obtain 0.1187+-0.0034(stat.)+-0.0019(syst).                            
     The strong coupling is also obtained, at lower precision,  from second    
     order fits of the c.m. energy evolution of some of the observabless.      
  
 Parallel session :3                   
 Plenary  session :11