Diana Hernández Diana Hernández studies housing, energy, health and equity with emphasis on evaluating the impacts of policies and structural changes in built environments. Greg Freyer Greg Freyer is one of the School’s most popular classroom instructors, and a 2015 winner of Columbia’s Teaching Excellence award. Barun Mathema Barun Mathema studies infectious disease epidemiology by considering multiple dimensions of transmission. Codruta Chiuzan Codruta Chiuzan studies the development of Phase I clinical trials with particular interest in cancer immunotherapeutic agents. Sara Abiola A lawyer and public health researcher with a focus on the empirical evaluation of health laws, Sara Abiola evaluates government interventions to improve population health. Helena Duch Helena Duch’s work focuses on the design and evaluation of preventive interventions in community-based settings, particularly in early childhood.