Abstract: Devices and techniques are generally described for on-time performance impact evaluation. In some examples, first flight plan data that includes a plurality of scheduled air-based routes may be determined. A first route of the plurality of scheduled air-based routes may be selected for a first package. First scan data related to the first package may be received. A first slack time associated with the first package on a first flight of the first route may be determined based at least in part on the first scan data. The first package being assigned to the first route may be evaluated based at least in part on the first slack time.

Abstract: The natural stereochemistry at the 13-position of avermectin aglycones, normally .alpha.-oriented or below the plane of the molecule, is inverted or epimerized into the .beta.-position. The procedure starts with the avermectin aglycone compounds where the 13.alpha.-hydroxy group is activated to a mesylate leaving group. The resultant 13-.alpha.-mesylate is then displaced with a cesium carboxylate and one equivalent of the respective carboxylic acid, ending with the ester group being converted to the 13-.beta.-hydroxy configuration by transesterification in high yield.