The past week has been full of bittersweet moments. Amid the excitement of the impending "head race" (http://en.wikipedia.org/wiki/Head_race) rowing season, I've found myself shivering and rubbing my hands together to increase circulation in the chilly morning air. Fog hung over the water three mornings in a row, making already-sleepy eyes heavier and wary of the unseen the meters ahead...   Thes…