(S (S (NP (BASENP (PRPD Their) (NN study)) (PP (IN of) (BASENP (NNP WASP-18b)))) (VP (VBD was) (VP (VBN published) (PP (IN in) (NP (BASENP (DT the) (NNP August) (NN 27) (NN issue)) (PP (IN of) (BASENP (DT the) (NN journal) (NNP Nature)))))))) (PERIOD .))