Pedro Cintra

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Peer Reviewed

Authors: J. P. Valeriano, P. H. P. Cintra, G. Libotte, I. Reis, F. N. Fontinele, R. Silva & S. Malta

Abstract: The long duration of the COVID-19 pandemic allowed for multiple bursts in the infection and death rates, the so-called epidemic waves. This complex behavior is no longer tractable by simple compartmental model and requires more sophisticated mathematical techniques for analyzing epidemic data and generating reliable forecasts. In this work, we propose a framework for analyzing complex dynamical systems by dividing the data in consecutive time-windows to be separately analyzed. We fit parameters for each timewindow through an approximate Bayesian computation (ABC) algorithm, and the posterior distribution of parameters obtained for one window is used as the prior distribution for the next window. This Bayesian learning approach is tested with data on COVID-19 cases in multiple countries and is shown to improve ABC performance and to produce good short-term forecasting.

Authors: I. B. F. Grebot, P. H. P. Cintra, E. F. F. de Lima, M. V. M. de Castro, & M. Jr., Rui

Abstract: Objective: The uncanny valley hypothesis refers to a subjective experience of eeriness to highly human-like objects (e.g., realistic avatars). There is evidence that objects at the human–avatar category boundary along the dimension of human likeness (DHL) are more likely to evoke the uncanny valley effect. Literature has focused on the affective domain of the phenomenon and studies on the cognitive demands are few. Here, we investigate whether perceptual ambiguity could affect the hierarchical processing of facial features. Our study investigated categorical perception of female and male faces along the DHL. Method: Participants performed a real vs. artificial categorization task and behavioral measures (categorization threshold and response time; RT) were calculated to determine avatar, boundary, and human face conditions. Results: An analysis on the hierarchy of gaze dwell time in regions of interest (ROI; eyes, nose, and mouth) showed greater dwell time for the nose area of boundary faces compared to the nose area of avatar and human faces. Conclusions: Results showed that perceptual discrimination difficulty changed the allocation of attentional resources in boundary faces. Such output may contribute on how we process artificial faces and might improve users’ experiences from highly realistic characters.

Authors: P. H. P. Cintra & F. N. Fontinele

Abstract: This paper attempts to provide methods to estimate the real scenario of the novel coronavirus pandemic in Brazil, specifically in the states of Sao Paulo, Pernambuco, Espirito Santo, Amazonas and the Federal District. By the use of a SEIRD mathematical model with age division, we predict the infection and death curves, stating the peak date for Brazil and above states. We also carry out a prediction for the ICU demand in these states and for how severe possible collapse in the local health system would be. Finally, we establish some future scenarios including the relaxation on social isolation and the introduction of vaccines and other efficient therapeutic treatments against the virus.

Conference Papers

Authors: J. P. Valeriano, P. H. P. Cintra, F. N. Fontinele, I. Reis, L. Lima, & T. L. S. Alves

Abstract: In order to verify the effects of using empirical priors to fit epidemiological models through the ABC- SMC method, we considered the SEIRD model with different prior distributions combinations, admitting experimental measurements or not. Comparing the results of these combinations, we observe that the fit with the minimal RMSD final value was the one using all available empirical distributions as priors. However, the values of the parameters obtained do not belong, in general, to the 95% CI of the empirical distributions. We further discuss possible reasons for this deviation.

Educational Purposes

Authors: P. H. P. Cintra

Abstract: O presente artigo tem a intenção de evidenciar as diferenças entre a análise clássica e quântica de uma molécula diatômica, nos aspectos das transições vibracionais, mostrando os resultados e predições de cada método, descrevendo as soluções e comparando elas com o comportamento real. Deixando claro as limitações e validades de cada método.