by the incessant use of cell phones 
(ROOT (PP (IN by) (NP (NP (DT the) (JJ incessant) (NN use)) (PP (IN of) (NP (NN cell) (NNS phones))))))
(ROOT (PP (IN ) (NP (NP (DT ) (JJ ) (NN )) (PP (IN ) (NP (NN ) (NNS ))))))