Measurements of Ru, Rd and Rs in e+e- Collisions at 189-202 GeV                
  
        The cross-section ratios Ru, Rd and Rs are measured for individual     
        light quarks using event samples collected with the OPAL detector      
        at LEP at centre-of-mass energies between 189 and 202 GeV. The         
        analysis uses high momentum charged pions, charged and neutral         
        kaons, protons and Lambda baryons to idenitify the different light     
        flavour quarks events on a statistical basis. The probabilities        
        for the                                                                
        different particle types to originate from particular primary quarks   
        are determined directly from data taken at the Z0 peak, thus making    
        possible a hadronisation model-independent measurement.                
  
 Parallel session :5                   
 Plenary  session :6a