This story about immigrant students was produced by The Hechinger Report, a nonprofit, independent news organization focused on inequality and innovation in education. IowaWatch is the exclusive Iowa partner. Sign up for the Hechinger newsletter. SIOUX CITY, Iowa — The rolling backpack was grey with bright orange zippers. Made by Totto, a popular South American brand, the backpack had been 13-year-old Cristian Rubio’s hand luggage on his flight from Ecuador to the United States a week earlier.