Can we identify non-stationary dynamics of trial-to-trial variability?"

Identifying sources of the apparent variability in non-stationary scenarios is a fundamental problem in many biological data analysis settings. For instance, neurophysiological responses to the same task often vary from each repetition of the same experiment (trial) to the next. The origin and functional role of this observed variability is one of the fundamental questions in neuroscience. The nature of such trial-to-trial dynamics however remains largely elusive to current data analysis approaches. A range of strategies have been proposed in modalities such as electro-encephalography but gaining a fundamental insight into latent sources of trial-to-trial variability in neural recordings is still a major challenge. In this paper, we present a proof-of-concept study to the analysis of trial-to-trial variability dynamics founded on non-autonomous dynamical systems. At this initial stage, we evaluate the capacity of a simple statistic based on the behaviour of trajectories in classification settings, the trajectory coherence, in order to identify trial-to-trial dynamics. First, we derive the conditions leading to observable changes in datasets generated by a compact dynamical system (the Duffing equation). This canonical system plays the role of a ubiquitous model of non-stationary supervised classification problems. Second, we estimate the coherence of class-trajectories in empirically reconstructed space of system states. We show how this analysis can discern variations attributable to non-autonomous deterministic processes from stochastic fluctuations. The analyses are benchmarked using simulated and two different real datasets which have been shown to exhibit attractor dynamics. As an illustrative example, we focused on the analysis of the rat's frontal cortex ensemble dynamics during a decision-making task. Results suggest that, in line with recent hypotheses, rather than internal noise, it is the deterministic trend which most likely underlies the observed trial-to-trial variability. Thus, the empirical tool developed within this study potentially allows us to infer the source of variability in in-vivo neural recordings

The challenge of responsible dispensing: formal education versus professional practice

The aim of the present study was to evaluate the education of Pharmaceutical Technicians for the activity of responsible dispensing. Based on a questionnaire with open and closed questions, the study sought to characterize the students, identify knowledge and attitudes regarding the Rational Use of Medications while addressing the limits and possibilities of professional and ethical dispensing in practice. In addition, a group dynamics session - focus group - was held as a forum for debate on responsible dispensing. The results showed that students tended to be mature, currently employed and were predominately women. Displaying adequate knowledge on Rational Use of Medications and of the corresponding legislation, the students reported difficulties exercising compatible practice. While the diagnosis pointed to the need for student preparation to enable ethical dispensing, the Focus Group highlighted the possibility for inclusion of a forum for reflection and debate on the ethics of dispensing as part of the Pharmaceutical Technician training.<br>O presente trabalho tem como proposta avaliar a formação do Técnico em Farmácia para o exercício da dispensação responsável. A partir de um questionário com perguntas fechadas e abertas, o estudo envolveu a caracterização dos alunos, a identificação de conhecimentos e atitudes em relação ao Uso Racional dos Medicamentos com vistas ao delineamento dos limites e possibilidades do exercício profissional ético na dispensação. Além disso, foi realizada uma dinâmica grupal - grupo focal - com o objetivo de apreciar a constituição de um espaço de reflexão sobre a dispensação responsável. Os resultados evidenciaram um alunato de maior idade, inserido no mercado de trabalho e predominância de mulheres. Dispondo de conhecimento adequado sobre o Uso Racional dos Medicamentos e da legislação correspondente os alunos fazem referência às dificuldades no exercício de uma prática condizente. Se o diagnóstico apontou para a necessidade de ser trabalhada a preparação do aluno para o desempenho ético na dispensação, o Grupo Focal apontou para a possibilidade de inclusão de espaços para reflexão e debate sobre a ética na dispensação no processo de formação do Técnico em Farmácia