In stochastic processes, chaos theory and time series analysis, detrended fluctuation analysis (DFA) is a method for determining the statistical self-affinity of a signal.
Sore throats caused by tonsillitis or streptococcus may trigger a canker sore even after the initial throat condition has subsided. Also known as an aphthous ulcer, canker sores are painful and unsightly, but they are not contagious.
Most commonly, mouth soresâwhich include canker soresâare a minor irritation and last only a week or two. In some cases, however, they can indicate mouth cancer or an infection, such as herpes simplex virus. Herpes simplex causes cold sores, or fever blisters, and is highly contagious.