Financial support: Projects FONDECYT 1030325 and 7040084.Keywords: dynamic models, Gibberella fujikuroi, Gibberellic acid, nonlinear models, parameter estimation, secondary metabolites, solid substrate cultivation. Abbreviations: NLP: non-linear programSeqSO: sequential solution/optimization SimSO: simultaneous solution/optimization SSF: Solid substrate fermentationCalibration of mechanistic kinetic models describing microorganism growth and secondary metabolite production on solid substrates is difficult due to model complexity given the sheer number of parameters needing to be estimated and violation of standard conditions of numerical regularity. We show how *Corresponding author advanced non-linear programming techniques can be applied to achieve fast and reliable calibration of a complex kinetic model describing growth of Gibberella fujikuroi and production of gibberellic acid on an inert solid support in glass columns. Experimental culture data was obtained under different temperature and Araya, M.M. et al.2 water activity conditions. Model differential equations were discretized using orthogonal collocations on finite elements while model calibration was formulated as a simultaneous solution/optimization problem. A special purpose optimization code (IPOPT) was used to solve the resulting large-scale non-linear program. Convergence proved much faster and a better fitting model was achieved in comparison with the standard sequential solution/optimization approach. Furthermore, statistical analysis showed that most parameter estimates were reliable and accurate.Solid substrate fermentation (SSF) can be defined as the cultivation of microorganisms on solid substrates devoid of or deficient in free water (Pandey, 2003). SSF has several advantages (Hölker and Lenz, 2005) over more conventional submerged fermentation, and many promising lab-scale SSF processes are periodically reported in the literature (John et al. 2006; Krasniewski et al. 2006;Lechner and Papinutti, 2006;Sabu et al. 2006). Unfortunately, very few of these processes enter commercial production (Hölker and Lenz, 2005) due to the magnitude of the technical difficulties in operating and optimizing large scale SSF bioreactors. Since modern process control and optimization engineering techniques are model based, mathematical modelling should significantly improve the chances of successfully transforming an SSF process from laboratory to commercial production.Nevertheless, a number of factors make modelling SSF processes particularly trying: the absence of reliable on-line measurements of relevant cultivation variables (like biomass and nutrient concentration) and the system's inherent complexity, considering that microorganism interaction with the environment and its growth and production kinetics are still not well understood on a micro scale (Mitchell et al. 2004). In addition, the more useful mechanistic dynamic models proposed are highly complex and have many parameters that need to be estimated from extensive good quality experimental data. Acq...

Participation of Chilean undergraduate medical students in scientific researchBackground: The participation of medical students in research generates professional, scientific, and personal benefits for the student. Aim: To evaluate the interest and opportunities for medical students in Chile to participate in scientific research and their perceptions about factors influencing research. Material and Methods: All students attending the 2018 Chilean Congress for Medical Students were invited to answer a 44 questions survey about interest and opportunities to participate in research. Results: The survey was answered by 489 of the 538 students attending the congress. Eighty five percent referred interest in conducting scientific research, but only 47% had the opportunity to actively participate in a research project. The main research area providing opportunities was epidemiology and the main form to access a research project was through direct contact with a medical professor or researcher. Seventy seven percent of respondents had courses of scientific investigation in their medical curriculum and 92% had a scientific society for medical students in their university. Conclusions: Respondents showed a great deal of interest in participating in scientific research. However, there is a gap between this interest and the available opportunities. Medical professors should promote and facilitate the participation of their students in research.

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