What are the standards for assessing the imposition of a sentence by the District Court?

We generally have declined to articulate precise standards for assessing the district court's imposition of a particular sentence, see United States v. Pereira, 465 F.3d 515, 524 (2d Cir. 2006), and are hesitant to require any specific incantations or utterances by the district court, see United States v. Rattoballi, 452 F.3d 127, 138 (2d Cir. 2006), abrogated in part on other grounds by Kimbrough v. United States, 552 U.S. 85 (2007). Nevertheless, district courts "must adequately explain the chosen sentence to allow for meaningful appellate review." Gall v. United States, 552 U.S. 38, 50 (2007).