The present invention relates to a novel 3,4-dihydro-1H-naphthalene derivative having a structure of formula 1 or formula 2, its pharmaceutically acceptable salts and their geometric isomers as a highly selective cyclooxygenase-2 inhibitor. The system also includes a head assembly having a head receptor shaped and dimensioned for direct attachment to a support and a head shaped and dimensioned for receipt within the head receptor for movement relative thereto. The disclosed logic devices perform one or more of AND, OR, NAND and NOR operations. The difference between the fraction of water in the intravascular fluid volume and extravascular fluid volume compartments are also determined. The slack causes the wing mower blades to cease turning.