Question: who proposed that atomic nucleus is positively charged
[{'answer': 'J.J. Thomson', 'provenance': [{'wikipedia_id': '19916559', 'title': 'Atomic nucleus', 'start_paragraph_id': 6, 'start_character': 183, 'end_paragraph_id': 6, 'end_character': 195, 'bleu_score': 1.0, 'section': 'Section::::Introduction.:History.\n'}]}, {'provenance': [{'wikipedia_id': '19916559', 'title': 'Atomic nucleus', 'start_paragraph_id': 6, 'start_character': 0, 'end_paragraph_id': 6, 'end_character': 1632, 'bleu_score': 0.992740351871881, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 13702064730815884631}, 'section': 'Section::::Introduction.:History.\n'}]}]