2633141 EFRs envelope following responses 60 2633139 EFRs environmental flow requirements 7 2633145 EFRs emerging flame retardants 6 2633147 EFRs emergency first responders 4 2633157 EFRs Early folding residues 1 2633148 EFRs ecological forest rangers 1 2633149 EFRs effective frequencies of recombination 1 2633146 EFRs elastomeric facepiece respirators 1 2633143 EFRs Emerging Flux Regions 1 2633144 EFRs emerging FRs 1 2633142 EFRs emerging halogenated FRs 1 2633140 EFRs escape failure responses 1 2633137 EFRs exhalation flow rates 1 2633138 EFRs extra-focal radiations 1 2633150 EFRs Extrafollicular plasmablast responses 1