In his 1931 monograph on the `` Constitution of Atomic Nuclei and Radioactivity '' , George Gamow , then at the Institute for Theoretical Physics in Copenhagen , did not mention the neutron .
ADP PRON NUM NOUN ADP DET `` PROPN ADP PROPN PROPN CCONJ PROPN '' , PROPN PROPN , ADV ADP DET PROPN ADP PROPN PROPN ADP PROPN , AUX PART VERB DET NOUN .