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le jeudi 23 février à 11:00

Tjalling JAGER

salle de formation du PRABI

par Vincent Daubin - 23 février 2012

Simplifying biology. Process-based models for toxicant effects and how
to apply them.

Living organisms are complex systems, and stressing them with toxicants
only increases the complexity. In ecotoxicology, the common strategy for
addressing toxic effects is to accept this complexity and provide
descriptions of parts of the response of the system. Such descriptions
will not advance our understanding and cannot address the problems of
environmental risk assessment. Complexity is of course not unique for
ecotoxicology. In related disciplines such as environmental chemistry,
the common approach is to simplify the system to its bare essence and
study the behaviour of the simplification. Something similar does exist
for toxic effects, which can be placed under the designation
“toxicokinetic-toxicodynamic” (TKTD) modelling. Toxicokinetics deals
with the uptake of chemicals into the organism, whereas toxicodynamics
addresses the relationship between internal concentrations and effects
over time. In this presentation, I will focus on toxicodynamic models,
and discuss how biology can be radically simplified to suit our purpose.
Furthermore, I demonstrate how experimental data can be analysed, and
discuss the statistical problems associated with fitting the models to data.