Thanks for the answer. The thing is, as far as I understand,

F-1 is a non-immigration oriented visa. Also H-4 holder is not allowed to work. And I certainly do not see any hope of getting a nobel prize (otherwise I do not need to switch my major field). So from what you said, do you mean that there is no requiremnt for applicant's visa status before sending out the NIW application? Again thank you for your answer.