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.
Much environmental art is ephemeral (made to disappear or transform), designed for a particular place (and can't be moved) or involves collaborations between artists and others, such as scientists, educators or community groups (distributed ownership).