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.
Canker sores are not contagious. Canker sores may also develop when you: 1  Are stressed or tired. 2  Have your menstrual cycle, if you are a woman. 3  Hurt your mouth, such as biting your lip. 4  Have braces on your teeth. 5  Have food allergies. 6  Eating foods that you are allergic to may cause you to get a canker sore.