A turnaround is in progress, but at a high cost.Starbucks (SBUX -2.52%) reported its fiscal third-quarter results, and global same-store sales slumped once again. It was the sixth straight quarter the company has seen its comparable-store sales decline.However, it's taking action to try to boost sales. This includes implementing a Green Apron Service model, which aims to create consistent, repeatable standards across its coffee shops. Starbucks said stores that have implemented the model have already had im ...