I published one article for The National (7)
I believe the answer is:
iranian
'the national' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe there's a link between them I don't understand?
'i published one article' is the wordplay.
'published' becomes 'ran' (running is a kind of publishing).
'one' becomes 'i' (Roman numeral).
'article' becomes 'an' (indefinite article).
'i'+'ran'+'i'+'an'='IRANIAN'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for iranian that I've seen before include "From Tehran, perhaps?" , "of Asian origin" , "from the Middle East" , "Tehran native, say" , "Native of modern Persia" .)