This paper discusses dynamic ARMA-type regression models for positive time series, which can handle bounded non-Gaussian time series without requiring data transformations. Our proposed model includes a conditional mean modeled by a dynamic structure containing autoregressive and moving average terms, time-varying covariates, unknown parameters, and link functions. Additionally, we present the PTSR package and discuss partial maximum likelihood estimation, asymptotic theory, hypothesis testing inference, diagnostic analysis, and forecasting for a variety of regression-based dynamic models for positive time series. A Monte Carlo simulation and a real data application are provided.

Oil has become a prevalent global pollutant, stimulating the research to improve the techniques to separate oil from water. Materials with special wetting properties—primarily those that repel water while attracting oil—have been proposed as suitable candidates for this task. However, one limitation in developing efficient substrates is the limited available volume for oil absorption. In this study, we investigate the efficacy of disordered fractal materials in addressing this challenge, leveraging their unique wetting properties. Using a combination of a continuous model and Monte Carlo simulations, we characterize the hydrophobicity and oleophilicity of substrates created through ballistic deposition (BD). Our results demonstrate that these materials exhibit high contact angles for water, confirming their hydrophobic nature while allowing significant oil penetration, indicative of oleophilic behavior. The available free volume within the substrates varies from 60% to 90% of the total volume of the substrate depending on some parameters of the BD. By combining their water and oil wetting properties with a high availability of volume, the fractal substrates analyzed in this work achieve an efficiency in separating oil from water of nearly 98%, which is significantly higher compared to micro-pillared surfaces made from the same material but lacking a fractal design.

Perspectival realism claims that scientific knowledge is always situated into a vantage point. We argue that ecological psychology offers a suitable framework to develop perspectival epistemologies. Ecological psychology stresses that perception is focused on affordances, i.e. the possibilities of interactions afforded by reality given the abilities of an organism. We call the integrating view as ecological perspectivism. It claims that science offers knowledge of reality in terms of affordances, which are relational to the instruments and abilities of scientific communities. Cognition is of affordances, and what a domain affords for scientists depends on which skills and technologies they avail. We connect this proposal with the main arguments for perspectivism. First, regarding instrumental detections, ecological perspectivism offers a realist account of perception that treats the use of instruments as tools that scaffold and extend embodied cognition. Second, regarding model pluralism, ecological perspectivism supports an artifactualist account of modelling as embodied cognition extended by tools. Such tools can be representational by receiving semantic interpretations that associate them with targets through the use of linguistic skills. Third, we promote Michella Massimi’s account of Natural Kinds with a Human Face. It treats kinds as open-ended groupings of phenomena that salient nomological dependencies. However, ecological perspectivism suggests that the realist content of scientific perspectives must be cashed out in terms of affordances, thereby reinterpreting the metaphysical notion of ‘phenomena’.

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Este artigo dialoga com a interpretação de Ethel Rocha (2016) acerca do escopo do método da dúvida cartesiana na Primeira Meditação, em especial no que tange à hipótese do sonho. Rocha sustenta que a dúvida de Descartes visa refutar o modelo escolástico de racionalidade — alicerçado na experiência sensível —, sem pôr em dúvida seu próprio paradigma racionalista. Para ela, a hipótese do sonho seria suficiente para abalar o princípio aristotélico-escolástico de que "não há nada no intelecto que não tenha antes passado pelos sentidos" (nihil est in intellectu quod non prius fuerit in sensu). Ampliando essa leitura, este estudo introduz no debate a teoria dos sentidos internos, tal como elaborada na recepção da psicologia aristotélica desde Avicena e assimilada pela escolástica tardia. Defendo que essa teoria confere maior robustez à tese de Rocha — de que Descartes busca persuadir um leitor versado na filosofia das Escolas —, ao demonstrar como o argumento do sonho visa especificamente processos dos sentidos internos, centrais à epistemologia escolástica. Contudo, a incorporação desse marco teórico revela duas divergências interpretativas: a dúvida do sonho deixaria intocado o valor epistêmico dos dados sensoriais originários dos sentidos externos; e, consequentemente, a confiabilidade desses dados deve ser questionada pelas razões metafísicas de duvidar.