There are multiple definitions:

1. ejection fraction to longitudinal strain ratio(English)

   • abnormal if > 4.1
   • EF, GLS, RALS
   • Cardiology, Ratio-based metric
   • https://doi.org…cmg.2019.10.011
   • https://doi.org…cmg.2015.11.013
   • https://doi.org…ging.116.005588

2. event-free survival rate(English)

   • Prognosis
   • https://doi.org…jcc.2014.06.006

3. exciton fine structure relaxation(English)

   • radiationless transition occurring in the exciton fine structure not only highlights a novel aspect of quantum dot exciton relaxation but also has implications for carrier spin relaxation in quantum dots
   • Biochemistry
   • https://doi.org….1021/ar8002046