Sound Ledger

925: The maximum speed in miles per hour of the new “quieter” supersonic jet

32: The percent by which harmful brain plaque, correlated with Alzheimer’s, was reduced in tests using focused ultrasound

45: The decibel level above which people generally find sound annoying

Sources: supersonic (nasa.gov), ultrasound (washingtonpost.com), decibels (wsj.com)