When a noun is used generally, an article is not needed.
General nouns are used frequently in academic writing. In academic English the singular form is usually replaced with a plural noun with no article. Sometimes the verb also needs to be changed.
Example 1
Language is normally the initial barrier for a refugee trying to integrate in a new country.
Replaced with: Language is normally the initial barrier for refugees trying to integrate in a new country. (Refugee is used generally so no article is needed.)
Example 2
The current work situation of an applicant was taken into account when selecting interviewees for the study.
Replaced with: The current work situations of applicants were taken into account when selecting interviewees for the study.
Example 3
The author argues that a university should be a place where critical thinking skills are taught.
Replaced with: The author argues that universities should be places where critical thinking skills are taught
Example 4
While some argue that a company should be strongly regulated by the state, others hold the view that too much regulation slows economic growth.
Replaced with: While some argue that companies should be strongly regulated by the state, others hold the view that too much regulation slows economic growth.
Sources: Cambridge Online Dictionary; British Council Learn English
