To provide an aluminum nitride powder and an aluminum nitride sintered body which satisfy both high thermal conductivity of an aluminum nitride sintered body and reduction in the shrinkage factor at the time of sintering. In one aspect of the present invention, there are provided ligands which are more selective for the retinoid X receptor than is retinoic acid. In response to user commands the method and apparatus provide additional nested indexes for the displayed data. Furthermore, a subsequent scan on the data is conditionally performed utilizing, each of a second plurality of scanners at a second network device, based on the at least one data structure. The multimedia session call control method includes these steps: a multi-UE party performs a multimedia session with a peer under control of an AS; a master UE of the multi-UE party establishes a session with a third party under control of the AS; and the AS binds a call leg between a slave UE of the multi-UE party and the AS to the session established with the third party. The content delivery server provides the digital content as a result of being contacted by a server-contacting program stored on a disk drive in the computer and initiated by the drive firmware.