Streets of Mexico City (IMAGE) Brown University Caption Paying at-risk populations to join programs of education and regular testing is an effective public health technique. Health economist Omar Galarraga studies the economic forces at work in Mexico City. Credit Omar Galarraga/Brown University Usage Restrictions With credit License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.