A system and method for updating a source copy of an ordered list comprising a plurality of list items according to modifications made to the order of the list items in a local copy of the ordered list is provided. Forming the single crystal AlGaN layer may comprise depositing AlGaN by vapor phase epitaxy using aluminum and gallium halide reactant gases and a nitrogen-containing reactant gas. The mounting point may be located at any point along the length of each tensioner. The scraper portion and rake are included in a single unit, attachable and detachable from the excavator bucket. When connected to any full fidelity sound system, a support structure, a full frequency response process promotes a state of relaxation in the listener. The chair swivels independently of the legs of the chair.