An improving earnings profile, aggressive buybacks, and a renewed focus on margins might be changing how long-term investors think about this healthcare distributor.Chicago-based Zuckerman Investment Group disclosed a purchase of 72,040 additional shares of Henry Schein (HSIC +0.28%) in a November 13 SEC filing, increasing its stake by approximately $3.38 million from the previous period.What HappenedAccording to a November 13 SEC filing, Zuckerman Investment Group increased its holding in Henry Schein (HSI ...