A medical graft connector or plug is made, for example, by cutting end portions of a tube of highly elastic material axially at numerous locations spaced circumferentially around the tube to produce a plurality of fingers which extend axially from each end of an uncut medial portion of the tube. In certain embodiments, user authentication may also be provided by issuing a ticket which is utilized to create, access and administer the files in the system. A predicate and an action of the first abstract rule may be used in translating the second abstract rule into an executable rule. The message server receiving the composed message for transmission to the recipient sends the message to the recipient in accordance with a priority determined based on the recipient’s electronic message resistance; for example, the message may be sent with a low priority attribute, or the transmission of the message to the recipient may be delayed for a set period of time. To achieve a good seal and centration of the pump housing, the pump housing is sealed by means of a resilient ring with respect to the cylindrical sealing surface of the transmission housing, with the ring being received by an outer peripheral groove of the pump housing with radial clearance so that the pump housing can adjust itself in the radial direction. Provides an effective tool to eliminate junk-mail by making it simpler and more practical to screen messages or change one’s e-mail address.