( ( ( RADIOACTIVITY -- ) ( Release ( of ( ( energy ( and ( energetic particles ) ) ) ( by ( changes ( occurring ( within ( atomic ( or ( nuclear structures ) ) ) ) ) ) ) ) ) ) ) . )
(ROOT (NP (NP (NNP RADIOACTIVITY)) (: --) (NP (NP (NNP Release)) (PP (IN of) (NP (NP (NN energy) (CC and) (JJ energetic) (NNS particles)) (PP (IN by) (NP (NP (NNS changes)) (VP (VBG occurring) (PP (IN within) (NP (JJ atomic) (CC or) (JJ nuclear) (NNS structures))))))))) (. .)))
RADIOACTIVITY--Release of energy and energetic particles by changes occurring within atomic or nuclear structures.
(ROOT (S (NP (NNP Radioactivity)) (VP (VP (VBZ is) (NP (NP (DT the) (NN release)) (PP (IN of) (NP (NNS particles))))) (CC and/or) (VP (NP (NN energy)) (PP (IN from) (NP (NP (DT the) (NN nucleus)) (PP (IN of) (NP (DT an) (NN atom))))))) (. .)))