Compounds of formula, methods for their preparation and their use in the manufacture of neuraminidase inhibitor conjugates. A first stage set of capacitors is operatively coupled to the level-crossing detector. The device can be used in processes for catalytic cracking of heavy hydrocarbons. Instead the slug piece may be of tantalum to provide a lower thermionic work function. This novel arrangement makes it unnecessary for the terminal device to input the personal information on its own.