psychological 
          and physical stress performance research having 
          to do with maintaining heightened concentration for long periods 
          of time as well as in extenuating circumstances or surroundings.  
           
          related products: 
           
            
            
            
            
           
           
          related [a]products: 
           
            
            
            
            
            
            
            
           
            
            
            
            
            
           
           
          further operative agencies: 
           
            
            
            
            
            
            
            
         
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