Personal Digital Assistant public display of affection Patent Ductus Arteriosus Principal Development Activity Preliminary Damage Assessment Personal Digital Assistants posterior descending artery Pressurized Docking Adapter Payload Disconnect Assembly Power Distribution Assembly Power Driven Arm Pregnancy Discrimination Act preliminary design approval Preliminary Design Audit Propellant Drain Area Parenteral Drug Association patent ductus arteriosis Percentage of Defectives Allowable personal data assistant Personal Display of Affection Phase Doppler Analysis Photon Detector Assembly poorly differentiated adenocarcinoma Portable Diagnostic Analyzer Portable Digital Assistant post-deposition anneal preliminary design acceptance preliminary design assessment preliminary design authorization PROBLEM DETERMINATION AID