1 Ghrelin is a fast-acting hormone that plays a vital role in meal initiation and contributes to weight gain.  Leptin mediates long-term regulation of energy balance and suppresses food intake, thereby inducing weight loss.
For the military, as for the civilian world, it is not overstating the point to say that the advent of radio communications has changed almost everything. The meerkat or suricate is a small mammal and a member of the mongoose family.
Dour refers to a stern and forbidding aspect, stony and unresponsive: dour rejection of friendly overtures. Surly implies gruffness of speech and manner, usually accompanied by an air of injury and ill temper: a surly reply.