DreamKing the fundamental difference of two, negative income tax is to encourage people to look for jobs, universal basic income is to encourage people to sit at home for doing nothing.
UBI is given to everybody, like air. The idea should not be still born because of those few, who exist in every society, who will contribute nothing to the economy and society as a result of getting a UBI. For all the others it will help to free them up to do what ever their passion is and society will benefit as a result.
When I was lecturing Business Information Systems at Wits, we would check in with first year students who did poorly in mid-year exams and often find that they really weren't interested in doing a B. Comm. but had been pressured into it by their parents. We all make the maximum contribution to society when we are doing something that we love.