I returned a revised paper to a journal. The paper had indicated that if I did what the referees said, which I did, the paper would be accepted. It is a math method, treating what is actually a difficult problem: If you have a set of measurements showing a smooth curve, how do you extract the first derivative of the curve at points along the curve? This is well known to be a very difficult problem if the data has noise, but I found an adequate method for my interests.

If the paper is accepted, it will be my second published paper this year.