Dallas/Denver or just simply BUMP,
'Tis a term used when a little extra oomph needs to be supplied to get the a/c out of (usually) hot and high airfields. I know it is fitted to GE90, V2500 and I think some operators CFM56's.
What it does is to provide extra cooling to the engine casing via the active turbine clearance control system. This further reduces the tip clearance and thus tip losses, so increasing engine efficiency and power for a given throttle position.
The trouble is that it reduces the clearance to such an extent that tip rub takes place so in the long term it actually degrades the engine efficiency. That is why a bump take off has to be recorded in the log because after a certain number the engine must be removed for inspection/overhaul.