Journal paper plagiarism, use of same words
If the conclusions are written in exactly the same manner in both papers, and the conclusions themselves are sufficiently long that there is no way the repetition could be "innocent" (for instance, "X increases with temperature when Y is present" can only be said so many ways!), then plagiarism has occurred.

In such a case, you should report the situation to the journal in which the later paper appeared and indicate that you believe plagiarism has occurred.