An expert on the impact of trauma on children says kids are durable, but parents need to be calm as the threat of terrorism hangs over the nation. James Garbarino spoke today in Des Moines at a forum on Iowa’s mental health system.Garbarino says kids aren’t wimps and can deal with adversity. He says kids, however, have been traumatized by the images of the collapsing buildings they saw on television.Garbarino says what makes today’s situation different from normal trauma is that it seems to have no end with the anthrax attacks and the F-B-I warnings of imminent danger.Garbarino says the good news is 80 percent of kids will be o-k. Garbarino says the 20 percent of kids who’ll have trouble coping are the kids who had other physical or emotional problems, like divorcing parents, before the September 11th attack.Garbarino says parents need to provide kids with structure. For example, he says the idea of NOT letting your kids celebrate Halloween is ludicrous. Garbarino has written 17 books. His latest is “Parents Under Siege” and chapter four is titled “The Dangerous World Outside Your Front Door.”