I used in the laboratory the Rotor Gene 6000 for a real time PCR and HRM analysis. When i analyzed the results of melting step, the derivative plot in the y-axis used the dF/dT . On the other hand when i read this guide on HRM analysis i saw that they use the negative derivative of dF/dT (-dF/dT).
Why would someone want to use the negative derivative instead of positive one ? Whats the difference between them?