Attention deficit hyperactivity disorder (ADHD) should be diagnosed and treated in children as young as age 4, according to new guidelines from the American Academy of Pediatrics. Skip to main content
ephemeris. 1  a table showing the positions of a heavenly body on a number of dates in a regular sequence. 2  an astronomical almanac containing such tables. 3  Archaic. an almanac or calendar.
An ephemeral life cycle is characterized by a short life and the capacity to leave behind very hardy forms of propagation. This ability is found not only in plants but also in many invertebrates. Desert ephemerals are amazingly rapid growers capable of reproducing at a remarkably high rate during good seasons.