In one aspect of the invention, there is provided a method for early detection of subacute, potentially catastrophic illness in an infant. When a new thread is spawned during execution of a computer program, new thread work area is allocated by the operating system in memory for storage of call stack information for the new thread. In operation, the dipole radiator portion operates in the lower end of the bandwidth and the Vivaldi radiator portion operates in the upper end of the bandwidth. A discharge space is formed between the first substrate and second substrate. The crossbar fastener is mounted on the other distal end of the collar and has two head-halves defining a tapered head. The substrate includes, deposited on the edges of its growth surface, a mask appropriate to prevent growing of the single crystal on the edges of the substrate.