This document discusses two studies: 1) A study of cassava starch production in Colombia which evaluated the sedimentation process in rectangular channels used. It found that particles greater than 10μm were efficiently retained in the first 104m, while particles between 6.7-8.8μm were discharged into local waterways. 2) A study of Spanish adolescents which analyzed sexual practices and protection methods based on age of sexual debut. It found that those with early debut (before 15) reported more partners and less condom use than later debut groups, suggesting early debut increases health risks.