There are multiple definitions:

1. astaxanthin(English)

   • PVA
   • Nano-sciences, Materials science
   • https://doi.org…853282221076229

2. atlas screw trajectory angle(English)

   • Orthopedics
   • https://doi.org/10.1111/os.13217

3. Arrhythmia-Specific questionnaire in Tachycardia and Arrhythmia(English)

   • a validated, disease-specific tool. It measures symptom burden and health-related quality of life (HRQoL) in patients with various forms of tachycardia and other arrhythmias
   • HRQoL
   • Cardiology, Electrophysiology, Questionnaire