Abstract: A method of mitigating contrails produced by an aircraft having a set of gas turbine engines, comprises the steps of (i) for each engine in a first subset of the engines, reducing the operating efficiency of the engine to produce a reduction in thrust provided by that engine and (ii) for each engine in a second subset, increasing the fuel flow to the engine to increase the thrust provided by that engine, the set of at least two gas turbine engines consisting of the first and second subsets. The method provides for contrail mitigation action by means of engine operating efficiency reduction to be directed to a first subset of engines for which contrail mitigation per unit engine operating efficiency reduction is greatest, the resulting reduction in thrust provided by such engines being at least partially compensated by increasing fuel flow to engines of the second subset.

Abstract: A “boil and bite” mouthguard including projections to improve molding of the mouthguard to the user's teeth is described. The mouthguard also includes a base-wall configuration that acts to minimize thinning of the base during molding and use of the mouthguard.

Abstract: A “boil and bite” mouthguard including projections to improve moulding of the mouthguard to the user's teeth is described. The mouthguard also includes a base-wall configuration that acts to minimise thinning of the base during moulding and use of the mouthguard.

Abstract: A “boil and bite” mouthguard including projections to improve moulding of the mouthguard to the user's teeth is described. The mouthguard also includes a base-wall configuration that acts to minimise thinning of the base during moulding and use of the mouthguard.

Abstract: A “boil and bite” mouthguard including projections to improve moulding of the mouthguard to the user's teeth is described. The mouthguard also includes a base-wall configuration that acts to minimise thinning of the base during moulding and use of the mouthguard.