E.g., a research paper on literary criticism or review does not look like it requires a CTA posts.
If we speak about facts of the influence of alcoholic beverages on human organism and body, such sort of academic papers may benefit from including call-to-action in the last sentence of the last paragraph.
As for the conclusion, you have to include all results points stated in each paragraph of article you give.
Writing an academic papers usually takes a lot of time and efforts.
A research paper may be longer than a typical essay.
Anyway you will have to know how to write a conclusions for a research papers as well.
If you address social needs, for example, your research paper will win from having a CTA.
You encourage people to invest more into charity or volunteer.
The only difference you have to understand is that you must restate your thesis in the first statement of your conclusion.
You may also do it in the last part of your entire research paper.