The FIA has confirmed that the qualifying format will change in Austin to reflect the fact that there are only18 cars in the entry.
As predicted by this writer last weekend four cars will be eliminated in Q1, and a further four in Q2. However Sebastian Vettel has already declared that he won’t participate in qualifying as a change to a complete sixth power unit will mandate a pitlane start, so in effect three cars will be bumped in Q1 this time.
Meanwhile the stewards have formally confirmed that Marussia and Caterham have both breached the regulations relating to entry in the championship by failing to turn up for the US GP.
The stewards have taken into account the ‘current financial circumstances’ of the teams had applied no penalty. However the matter has been referred to FIA President Jean Todt.
Adam Cooper's F1 Blog 
Actually, following from your earlier post, it seems complete bull$hit that the meeting’s stewards should even have to bother their heads over the two no shows. Seems completely beyond their area of concern?
“…the matter has been referred to FIA President Jean Todt”
And he’ll file it in the ‘Who gives a f**k’ box. The FIA and in particular Todt, are spineless.