radioactive tracer
In Metabolic studies, scientist want to follow the flow of molecules. So, the animals or cells used in these types of studies are grown with radioactive media. Sometime the nitrogen is radioactive, sometimes it's carbon and sometimes it's sulfur. Steven Spielberg wanted the audience to be able to follow the life of one of the victims in this movie, so he colored the little girl in red so that her life and death could easily be followed.
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.