A marine engine exhaust system has an exhaust conduit conveying engine exhaust gas from upstream to downstream, a sensor sensing oxygen content of the exhaust gas in the conduit, and a shield located in the conduit. A wire harness has a wire harness main body including at least one electric wire and a protection member. The alpha-olefin polymer may comprise an interpolymer of ethylene and octene, while the ethylene-carboxylic acid copolymer may comprise ethylene-acrylic acid copolymer. An air mover creates a differential pressure sufficient to effect a desired physical or biochemical change in the soil adjacent the conduits, variously to to an extent sufficient to push water from saturated soil and to change the gas composition in the soil. ISCs can be incorporated into fluorescent microscopy instruments to provide high-speed, fine-tune control over the irradiance of excitation beams.