ABSTRACT The curve of cumulative cases of individuals infected by COVID-19 shows similar growth to the logistic curve in the period referring to each epidemic “wave”, as each peak of active cases is called. Considering that in pandemic scenarios it is common to seek control measures based on previous experiences, in this paper we model the curve of cumulative cases through a logistic model with infected removal to include the control measures in the dynamics. This model is based on fractional differential equations to also include the memory effect. We study the scenario of the first two “waves” in the analyzed countries: Brazil, China, Italy, and Switzerland. Scenarios with and without control measures are compared, proving the importance of control measures such as isolation. Moreover, this model makes it possible to determine the portion of the population that did not participate in the dynamics of the spread of the disease, as well as to analyze how the number of infected people reduced in each country.

ABSTRACT Treatment with antiviral drugs for human immunodeficiency virus type 1 (HIV-1) infection causes a rapid reduction in plasma viral load. Viral decline occurs in several stages and provides information on important kinetic constants of virus replication in vivo and pharmacodynamic properties. We present a mathematical model that not only considers the intracellular phase of the viral life cycle, defined as the time between the infection of a cell and the production of new viral particles, but we also consider that this parameter together with the virus decay are interactive fuzzy numbers.

RESUMEN El gorgojo Acanthoscelides obtectus (Say) (Coleoptera: Chrysomelidae: Bruchinae) es una plaga cosmopolita que causa grandes pérdidas en frijoles almacenados, ya sea em pequenas unidades o en fincas. Aquí, se probó la eficacia del polvo inerte de la tierra de diatomeas (DE) como una alternativa para controlar A. obtectus en frijoles comunes Phaseolus vulgaris L., en diferentes temperaturas de almacenamiento e intervalos de exposición. Usando un diseño completamente al azar, cuatro dosis (0.25, 0.50, 0.75 y 1.00g kg-1) de tierra de diatomeas en frijoles mantenidos a diferentes temperaturas (25, 28, 30, 32 y 35 °C). La mortalidad de los insectos se evaluó después de dos o cinco días de exposición. Se evaluaron los impactos de la tierra de diatomeas en la descendencia de adultos de A. obtectus expuestos a cinco días. La producción de descendencia (adultos emergentes) se evaluó 60 días después de la exposición. Los resultados mostraron que la mortalidad por A. obtectus causada por la tierra de diatomeas dependía de la dosis, la temperatura y el período de exposición. Por ejemplo, a la temperatura más baja (25 °C), la dosis de tierra de diatomeas (0.25 g kg-1 de frijoles) y el período de exposición de dos días, la eficacia de la tierra de diatomeas se redujo significativamente en comparación con los otros tratamientos. Cuando se aplica a temperaturas superiores a 30 °C, los tratamientos con tierra de diatomeas siempre dieron como resultado una mortalidad de A. obtectus de al menos 90%. Curiosamente, la producción de descendencia (F1) se redujo a más del 95% en todos los tratamientos de tierra de diatomeas, temperaturas y períodos de exposición. Por lo tanto, los resultados demostraron que la tierra de diatomeas tiene el potencial de ser utilizada como una herramienta para controlar las infestaciones de A. obtectus en frijoles almacenados, considerando que dicha práctica de control redujo adecuadamente estas infestaciones de insectos en varios escenarios posibles.

ABSTRACT The weevil Acanthoscelides obtectus (Say) (Coleoptera: Chrysomelidae: Bruchinae) is a cosmopolitan pest that causes high losses in stored beans in small storage units and especially on-farm storages. Here, it was tested the efficacy of the inert dust diatomaceous earth (DE) as an alternative to control A. obtectus in common beans (i.e., Phaseolus vulgaris L.) on different storage temperatures and exposure intervals. Using a Completely Randomized design four doses (0.25, 0.50, 0.75 and 1.00g kg-1) of diatomaceous earth on beans kept at different temperatures (25, 28, 30, 32 and 35°C). Insect mortality was evaluated after two or five days of exposure. The impacts of diatomaceous earth in the offspring of five days-exposed A. obtectus adults were evaluated. The offspring production (emerged adults) was evaluated 60 days after the exposure. The results revealed that A. obtectus mortality caused by diatomaceous earth was dose, temperature and exposure period dependent. For instance, at the lowest temperature (25°C), diatomaceous earth dose (0.25g kg-1 of beans) and exposure period of two days, the efficacy of diatomaceous earth was significantly reduced when compared to the other treatments. When applied at temperatures above 30°C, the diatomaceous earth treatments always resulted in A. obtectus mortality of at least 90%. Curiously, offspring production (F1) was reduced to over 95% in all diatomaceous earth, temperatures and exposure period treatments. Therefore, the results demonstrated that diatomaceous earth has the potential to be used as a tool to manage A. obtectus infestations in stored beans, considering that such control practice adequately reduced these insect infestations in several possible scenarios.

Resumen Los efectos de los pesticidas sobre los enemigos naturales en un agroecosistema son de suma importancia para los programas de manejo integrado de plagas. Los enemigos naturales pueden estar sujetos a la exposición directa e indirecta de insecticidas y moléculas sinérgicas (por ejemplo, cloruro de sodio - NaCl) que se utilizan para controlar diversas plagas de cultivos agrícolas como la soja. Aquí, evaluamos los posibles efectos del imidacloprid y su interacción con NaCl como un potenciador de la supervivencia y las capacidades reproductivas del depredador no objetivo Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae Los insectos fueron expuestos a una tasa de campo de imidacloprid, recomendado para controlar los chinches en campos de soya. La solución de imidacloprid fue mezclada (o no) con NaCl (0.5%, w/v). El NaCl como potenciador de pesticidas no afectó la supervivencia de los adultos de P. nigrispinus después de 48 h de exposición (siempre se registró menos del 12% de mortalidad). Sin embargo, la mortalidad de la ninfa del quinto estadio fue casi del 50%. Los efectos de imidacloprid sobre los parámetros reproductivos de P. nigrispinus incluyeron una disminución en la oviposición, mostrando menos huevos por día. Sin embargo, la fertilidad no se vio afectada. La adición de NaCl, por lo tanto, no tuvo efecto sobre la mortalidad, supervivencia y reproducción del depredador no objetivo. El uso de NaCl asociado a imidacloprid y otros pesticidas en presencia de P. nigrispinus demostró compatibilidad, sin embargo, requiere una evaluación adicional para respaldar el conjunto de estas estrategias de control de plagas.

Abstract Pesticide effects on natural enemies in an agroecosystem are of paramount importance for integrated pest management programs. Natural enemies can be subject to direct and indirect exposure to insecticides and synergistic molecules (e.g., sodium chloride - NaCl) which are used to control various pests of agricultural crops such as soybean. Here, we evaluated the potential effects of imidacloprid and its interaction with NaCl as an enhancer on the survival and reproductive abilities of the non-target predator Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae). The insects were exposed to the stink bugs control field recommended dose of imidacloprid associated or not with the salt at the concentration of 0.5% (w/v). NaCl as a pesticide enhancer did not affect the survival of P. nigrispinus adults after 48 h of exposure (less than 12% of mortality was always recorded). However, the fifth instar nymph mortality was almost 50%. The effects of imidacloprid on the reproductive parameters of P. nigrispinus included a decrease in the oviposition, showing fewer eggs per day. However, the fertility was not affected. The NaCl addition, therefore, had no effect on the mortality, survival, and reproduction of the non-target predator. The use of NaCl associated to imidacloprid and other pesticides in the presence of P. nigrispinus demonstrated compatibility, however, it requires further evaluation to endorse the set of these pest control strategies.

RESUMO Nesta revisão de literatura, abordamos a importância da atenção seletiva, da inibição e da memória de trabalho na aprendizagem das crianças. Começamos por apresentar as suas definições e principais mecanismos funcionais. Apresentamos igualmente conclusões de vários estudos que abordam a importância desses processos, sobretudo em tarefas visuoespaciais. Finalmente, abordamos o papel que o ambiente visual circundante desempenha na aprendizagem, chamando a atenção para uma lacuna que se verifica em grande parte dos estudos: a sua pouca validade ecológica. É também defendido que o ambiente visual externo deve ser considerado nos modelos explicativos dos processos cognitivos básicos. Conclui-se o trabalho alertando para a necessidade de se estudar de forma mais sistemática a relação entre estes dois elementos (cognição e ambiente).

ABSTRACT This literature review focuses on the importance of selective attention, inhibition and working memory in children's learning. We start by presenting the definition and functional mechanisms of these cognitive processes. We then present the main results of several studies that report the importance of these processes, particularly in visuospatial tasks. We also discuss the role of the visual surrounding environment in learning, particularly with respect to an existing gap in most studies: Their low ecological validity. We argue for the importance of considering the visual external environment when trying to explain performance in basic cognitive processes. Finally, we stress the need for more empirical studies exploring in a systematic way the relation between these two elements (cognition and environment).

O consumo excessivo de álcool em estudantes universitários tem sido foco de grandes preocupações, não só devido aos seus efeitos negativos na saúde, mas porque habitualmente leva a comportamentos de risco, como a condução sob o efeito de álcool, ou relações sexuais sem proteção. Outro aspeto muito verificado entre os estudantes universitários, e que parece estar associado ao consumo de álcool, são os elevados níveis de stress, provavelmente um dos motivos que leva ao consumo de álcool. Neste estudo, realizado a 760 estudantes da Universidade de Aveiro, verificámos que os participantes apresentam elevados consumos de álcool, sobretudo em festas académicas. Os comportamentos de risco associados não se mostram significativos. Verificámos igualmente que o maior consumo de álcool está associado ao sexo masculino. Também se constatou que os estudantes universitários que saem de casa dos pais/da sua residência apresentam maiores consumos de álcool. Relativamente à perceção de stress, verificámos que os estudantes universitários de Aveiro apresentam níveis moderados de stress e que estes se encontram negativamente correlacionados com os consumos de álcool. Os nossos resultados são discutidos à luz das teorias existentes sobre os padrões de consumo de álcool em estudantes universitários.

The excessive alcohol consumption in college students has been the focus of enormous concerns, not only because alcohol has negative effects on people’s health, but also because it frequently leads to risky behaviors, for instance, drinking and driving or having sexual relations without any protection. Another aspect that has been identified in college students, and seems to be associated with alcohol consumption, is stress, which is probably one of the reasons that encourage alcohol consumption. In the present study, which has been conducted with 760 students at the University of Aveiro, we found that students consume large quantities of alcohol, particularly in academic celebrations. However, the risky behaviors are not significant in our sample. We also found that higher levels of alcohol consumption are associated with male students and with students who are dislocated from their families’ house. As far as stress perception is concerned, our sample shows a medium level of stress. Students’ stress is negatively correlated with alcohol consumption. Our results are discussed in the light of the existing theories about alcohol consumption in college students.