Profession is a synonym of Occupation. Position is a type of Occupation. Position is related to Mayor. Mayor can be used for Leadership. 
Medicine is related to Science. you are likely to find Science in/at/on University. you are likely to find Book in/at/on University. Book is related to Publication. 
Profession <--Synonym--> Occupation <--IsA-- Position <--RelatedTo--> Mayor --UsedFor--> Leadership 
Medicine <--RelatedTo--> Science --AtLocation--> University <--AtLocation-- Book <--RelatedTo--> Publication 