Techniques for comparing documents may be provided. The apparatus has a rotatable hub for the mounting of a buffed tire casing. A pointed tip of the cathode is juxtaposed by a central hole in a face of the anode and a small gap between them. Alternatively, a constant modulus algorithm can be used for beam forming operations. Also pharmaceutical compositions comprising the above compounds and methods wherein the above compounds are used for treatment of disorders in the central nervous system are disclosed.