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This study presents a proposal for an action-research approach to teaching practice following a qualitative document research methodology, applying the anthropological theory of the didactic and the theory of meaningful learning to Chemical Kinetics, a curriculum present in Brazilian high school education. Within this practice, developing a methodology to facilitate the calculation of reaction orders, enhancing the roles of teachers and students, raised questions to be answered: What impact does a methodology focused on the order of chemical reaction have, starting from a problem whose aim is to develop skills and competences that promote the formation of teachers and students, provoking a change in attitude towards socio-environmental issues? Many omissions in wise knowledge and few didactic creations related to experimentation and the process of mathematical modeling were identified in the literature researched. However, in this work, the teaching time in relation to the content and the learning time of the students was respected, and the strategy proved effective in the meaningful, transposition, and praxeological scopes. [ABSTRACT FROM AUTHOR]

The Irati Formation located in Southern Brazil is the world’s second largest resource of oil shale from which shale oil has been produced by Petrobras, a Brazilian state-owned oil company, by the Petrosix® process. The shale plant was sold to a private company in November 2022. This study analyses the mass and heat transfer between oil shale particles and a gas medium by mathematical modelling using Fortran programs, focusing on the temperature and moisture gradients within the shale particles. It also carries out parametric sensitivity analysis regarding shale thermal conductivity, heat transfer coefficient, effective mass diffusivity, shale density and size. The particle size and effective mass diffusivity have a great impact on heat and mass transfer. [ABSTRACT FROM AUTHOR]

The purpose of this article is to discuss the conditions that would make it possible for the Mathematical Modelling argument to emerge in Brazilian Mathematics Education. To this end, we have used theoretical and methodological resources linked to theories by the philosopher Michel Foucault. The analytical material covers master’s and doctoral theses developed in Brazil between the years 1976 and 1999, which have conceptualized Mathematical Modeling in Mathematics Education. The analysis of such studies has made it evident that the concept of Mathematical Modeling occurs during a crisis in Mathematics teaching, which has been discussed here from the following statement: “Mathematics is distant from reality”. We could conclude that the Modern Mathematics Movement made the emergence of Mathematical Modeling possible in Mathematics Education. The reason for that is that it would provide for interdisciplinary work - minimizing the distance between Mathematics and reality - thus, it would bring meaning to the teaching and learning of Mathematics - mitigating the difficulties students go through to learn it. [ABSTRACT FROM AUTHOR]

Background: Hepatitis A is responsible for 126,000,000 cases of acute viral hepatitis distributed heterogeneously worldwide, with a high disability-adjusted life year (DALY) rate, especially in low-income countries. Data related to Hepatitis A provides information to improve control measures and identify the population at risk. This study aims to analyze temporal trends of Hepatitis A in Brazil and its regions from 2007 to 2018, based on official notification data. Methods: Data related to Hepatitis A reported cases from 2007 to 2018 were fitted to a joinpoint model by Brazilian regions, age groups, and gender, allowing the calculation of average annual percentage change (AAPC) and annual percentage change (APC) to estimate trends of Hepatitis A in Brazil. Findings: From 2007 to 2018, 65,284 Hepatitis A cases notified in Brazil were available for analysis. The Northeast Region reported 18,732 (28.69%) cases, followed by the North Region reporting 18,430 (28.23%), the Southeast Region reporting 14,073 (21.55%), the South Region reporting 7909 (12.11%), and the Central-West Region reporting 6140 (9.4%), respectively. Temporal trend analysis showed that Hepatitis A incidence decreased from 2007 to 2016 in all Brazilian regions for individuals less than 20 years old, but increased in the South and Southeast males between 20 to 39 years after 2016. Conclusions: Hepatitis A endemicity is heterogeneous among Brazilian regions. In addition, an unexpected outbreak of HAV among Southeast and South adult males in 2016 resembles the outbreak in Europe, revealing a vulnerable population that should be prioritized by vaccination programs and control measures. [ABSTRACT FROM AUTHOR]

To truly understand the hydrologic and erosive processes that occur at the catchment scale regarding land use and soil management changes, intensive monitoring is required over a long period. Variables such as precipitation, flow rate and suspended sediment concentration are the fundamentals needed to estimate sediment yield (SY). However, in order to shed more light on the effects of soil management changes on SY, traditional hydrologic monitoring techniques can be paired with sediment tracing to identify sediment sources. In addition, mathematical models that predict erosion and SY can also help understand the dynamics of erosion and deposition between the hillslope and stream channel. Given the above, this article provides an overview of almost 20 years of monitoring (2002–2021) in the Arvorezinha experimental catchment (1.23 km2) located on the edge of the Brazilian meridional plateau in southern Brazil, which is subject to extreme erosion due to a combination of factors related to intensive agriculture and steep slopes. The catchment was selected as a study site to evaluate the effects of land‐use changes and soil conservation management on hydrology and SY. The text reviews the history of the study, synthesizes the main results and describes the evolution of the monitoring techniques used while giving special attention to the fingerprinting approach. In addition, the article discusses the importance of catchment‐scale studies for teaching, generating technical‐scientific knowledge and fostering collaboration between national and international research groups. [ABSTRACT FROM AUTHOR]

Coffee is one of the mostly consumed beverages worldwide. Roasting of coffee is an important process causing many changes in the quality and sensory characteristics of coffee beans. The objective of this study was the determination of the effect of roasting on the physicochemical and sensory properties and comparison of six coffee varieties, namely Brazil Santos, Brazil Rio Minas, Mexico Finca Muxbal, Guatemala Shb Ep, Ethiopia Djimmah, and India Robusta. Coffee beans were subjected to heat treatment at air temperatures up to 270 °C for up to 20–27 min, depending on the coffee variety and the desirable roasting degree. During the whole process, various physicochemical properties (mass, volume, density, color) and sorption isotherms of coffee beans were measured. For sensory evaluation, arabian and espresso beverages were prepared. Color of coffee beans darkened with increasing time and temperature during roasting, while volume increased. Total mass loss was also observed. Sorption isotherms followed type III, except for the variety India Robusta and the raw samples that followed type II. Sensory characteristics were distinctly different for each of the studied varieties. In arabian coffee drinks the color of cream was darker compared to espresso drinks and presented less acid and sour taste. Concerning texture, the body was positively evaluated both in arabian and espresso drinks. [ABSTRACT FROM AUTHOR]

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Observational data and numerical modeling were used to investigate oceanic current wakes surrounding Fernando de Noronha Island (3°51′S–32°25′W) and Rocas Atoll (3°52′S–33°49′W). These two Brazilian systems are located in the western tropical Atlantic region and are under the influence of the westward flow of the central South Equatorial Current (cSEC). In order to highlight the effects of wakes on ocean dynamics, two different numerical simulations were performed, using the Regional Oceanic Modeling System (ROMS): the first one including Fernando de Noronha Island and Rocas Atoll (Scenario I) and the second one with artificial removal of the island and atoll (Scenario NI). Simulations are validated through the Scenario I that well reproduces the wakes that give rise to the development of eddies downstream of FN and AR. These mesoscale structures have a strong influence on the thermodynamic properties surrounding the Island and the Atoll. Scenario NI allows evidence of the presence of an Island and Atoll shoaling mixed layer throughout the year, primarily on the western side of the Island and the Atoll. Mixing at the base of the mixed layer, inducing a subsurface cooling, is also enhanced in the downstream portion of the Island and Atoll, particularly when the cSEC is strengthened. These simulations support the “island mass effect” on the high productivity of subsurface waters generally observed on the western side of these islands. [ABSTRACT FROM AUTHOR]

The article discusses the application of the PY Refdif S parabolic mild-slope model in the study of irregular wave propagation from offshore to nearshore in Torres-Mostardas region in Rio Grande do Sul, Brazil. It says that Refdif simulates the deformation and propagation of irregular waves in coastal areas having variable water depth. It mentions that linear superposition was used as the method in the study of irregular wave propagation.

The objective of this article is to present a current panorama of research on mathematical modelling in Brazilian mathematics education by approaching it from three perspectives. The first addresses the historical roots of this field of knowledge in Brazil, highlighting the relationship with the international community, masters and doctoral research, and some important forums dedicated to modelling in Brazil. The second is a synthesis of some existing works also dedicated to the discussion of Brazilian research and publications related to modelling in mathematics education. The third perspective consists of description and analysis of research, in terms of the authors’ proposed objectives, presented in recent national scientific events, seeking to characterize and comprehend current interests that move research in this field. Based on this panorama, I offer some cautionary notes to Brazilian researchers regarding care to be taken when proposing new research in modelling in mathematics education, and I present a proposal for future studies. [ABSTRACT FROM AUTHOR]

In this research, the atrazine adsorption onto activated biochar produced from corn straw was evaluated based on kinetic and equilibrium studies and physical, chemical and morphological analyses. Batch adsorption experiments were performed to obtain kinetic and equilibrium parameters which were used to simulate the process' performance on fixed-bed column. The activated biochar showed specific surface area, total pore volume and average pore radius of 573 m2 g−1, 0.3054 cm3 g−1 and 10.7 Å, respectively, while the non-activated biochar exhibited lower specific surface area (504 m² g−1) in comparison with the activated biochar. The atrazine adsorption mechanism was predominantly driven by hydrogen bonds and π-π stacking. The experimental equilibrium data was adequately described by Langmuir isotherm, showing high adsorbate-adsorbent affinity (K L = 4.287 L mg−1). The adsorbent also showed favorable kinetics which was well described by the intraparticle diffusion model. The atrazine adsorption dynamics on fixed-bed column packed with the produced biochar was investigated by using an experimental design associated to phenomenological mathematical modeling. The approach was able to predict the column behavior from the batch parameters and was experimentally validated, showing an efficiency of 72% and breakthrough time of 520 min. The results evidenced the effectiveness of the produced biochar to remove atrazine from water as well as the model to adequately predict the batch and column's performance. [Display omitted] • Biochar produced from an abundant waste material (corn straw) in Brazil. • A major contribution of micropores was observed in porous structure. • Robustness identification of kinetic and equilibrium parameters from batch studies. • Phenomenological-statistical modeling was successfully used in fixed-bed study. • Biochar was efficient in atrazine removal on fixed-bed column. [ABSTRACT FROM AUTHOR]

Backgrounds: Brazil has suffered two waves of Coronavirus Disease 2019 (COVID-19). The second wave, coinciding with the spread of the Gamma variant, was more severe than the first wave. Studies have not yet reached a conclusion on some issues including the extent of reinfection, the infection fatality rate (IFR), the infection attack rate (IAR) and the effects of the vaccination campaign in Brazil, though it was reported that confirmed reinfection was at a low level., Methods: We modify the classical Susceptible-Exposed-Infectious-Recovered (SEIR) model with additional class for severe cases, vaccination and time-varying transmission rates. We fit the model to the severe acute respiratory infection (SARI) deaths, which is a proxy of the COVID-19 deaths, in 20 Brazilian cities with the large number of death tolls. We evaluate the vaccination effect by a contrast of "with" vaccination actual scenario and "without" vaccination in a counterfactual scenario. We evaluate the model performance when the reinfection is absent in the model., Results: In the 20 Brazilian cities, the model simulated death matched the reported deaths reasonably well. The effect of the vaccination varies across cities. The estimated median IFR is around 1.2%., Conclusion: Overall, through this modeling exercise, we conclude that the effects of vaccination campaigns vary across cites and the reinfection is not crucial for the second wave. The relatively high IFR could be due to the breakdown of medical system in many cities.

During the coronavirus disease 2019 (COVID-19) pandemic, many countries opted for strict public health measures, including closing schools. After some time, they have started relaxing some of those restrictions. To avoid overwhelming health systems, predictions for the number of new COVID-19 cases need to be considered when choosing a school reopening strategy. Using a computer simulation based on a stochastic compartmental model that includes a heterogeneous and dynamic network, we analyse different strategies to reopen schools in the São Paulo Metropolitan Area, including one similar to the official reopening plan. Our model allows us to describe different types of relations between people, each type with a different infectiousness. Based on our simulations and model assumptions, our results indicate that reopening schools with all students at once has a big impact on the number of new COVID-19 cases, which could cause a collapse of the health system. On the other hand, our results also show that a controlled school reopening could possibly avoid the collapse of the health system, depending on how people follow sanitary measures. We estimate that postponing the schools' return date for after a vaccine becomes available may save tens of thousands of lives just in the São Paulo Metropolitan Area compared to a controlled reopening considering a worst-case scenario. We also discuss our model constraints and the uncertainty of its parameters.

In this paper, we present a method to estimate the risk of reopening of schools illustrated with the case of the State of São Paulo, Brazil. The model showed that, although no death of children would result from the reopening of the schools in the three cities analysed, the risk of asymptomatic and symptomatic cases and secondary cases among teachers, school staff and relatives of the children is not negligible. Although the epidemic hit different regions with different intensities, our model shows that, for regions where the incidence profile is similar to the cities analysed, the risk of reopening of schools is still too high. This in spite of the fact that incidences in these cities were declining in the period of the time considered. Therefore, although we cannot extend the result to the entire country, the overall conclusion is valid for regions with a declining incidence and it is even more valid for regions where incidence is increasing. We assumed a very conservative level of infection transmissibility of children of just 10% as that of adults. In spite of the very low level of transmissibility is assumed, the number of secondary cases caused by infected children among teachers, school staff and relatives varied from 2 to 85. It is, therefore, too soon to have any degree of confidence that reopening of schools before the advent of a vaccine is the right decision to take. The purpose of our model and simulations is to provide a method to estimate the risk of school reopening, although we are sure it could be applied as a guide to public health strategies.

Introduction: Little evidence exists on the differential health effects of COVID-19 on disadvantaged population groups. Here we characterise the differential risk of hospitalisation and death in São Paulo state, Brazil, and show how vulnerability to COVID-19 is shaped by socioeconomic inequalities., Methods: We conducted a cross-sectional study using hospitalised severe acute respiratory infections notified from March to August 2020 in the Sistema de Monitoramento Inteligente de São Paulo database. We examined the risk of hospitalisation and death by race and socioeconomic status using multiple data sets for individual-level and spatiotemporal analyses. We explained these inequalities according to differences in daily mobility from mobile phone data, teleworking behaviour and comorbidities., Results: Throughout the study period, patients living in the 40% poorest areas were more likely to die when compared with patients living in the 5% wealthiest areas (OR: 1.60, 95% CI 1.48 to 1.74) and were more likely to be hospitalised between April and July 2020 (OR: 1.08, 95% CI 1.04 to 1.12). Black and Pardo individuals were more likely to be hospitalised when compared with White individuals (OR: 1.41, 95% CI 1.37 to 1.46; OR: 1.26, 95% CI 1.23 to 1.28, respectively), and were more likely to die (OR: 1.13, 95% CI 1.07 to 1.19; 1.07, 95% CI 1.04 to 1.10, respectively) between April and July 2020. Once hospitalised, patients treated in public hospitals were more likely to die than patients in private hospitals (OR: 1.40%, 95% CI 1.34% to 1.46%). Black individuals and those with low education attainment were more likely to have one or more comorbidities, respectively (OR: 1.29, 95% CI 1.19 to 1.39; 1.36, 95% CI 1.27 to 1.45)., Conclusions: Low-income and Black and Pardo communities are more likely to die with COVID-19. This is associated with differential access to quality healthcare, ability to self-isolate and the higher prevalence of comorbidities., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.)

Background: The parasite Leishmania infantum causes zoonotic visceral leishmaniasis (VL), a potentially fatal vector-borne disease of canids and humans. Zoonotic VL poses a significant risk to public health, with regions of Latin America being particularly afflicted by the disease. Leishmania infantum parasites are transmitted between hosts during blood-feeding by infected female phlebotomine sand flies. With a principal reservoir host of L. infantum being domestic dogs, limiting prevalence in this reservoir may result in a reduced risk of infection for the human population. To this end, a primary focus of research efforts has been to understand disease transmission dynamics among dogs. One way this can be achieved is through the use of mathematical models., Methods: We have developed a stochastic, spatial, individual-based mechanistic model of L. infantum transmission in domestic dogs. The model framework was applied to a rural Brazilian village setting with parameter values informed by fieldwork and laboratory data. To ensure household and sand fly populations were realistic, we statistically fitted distributions for these entities to existing survey data. To identify the model parameters of highest importance, we performed a stochastic parameter sensitivity analysis of the prevalence of infection among dogs to the model parameters., Results: We computed parametric distributions for the number of humans and animals per household and a non-parametric temporal profile for sand fly abundance. The stochastic parameter sensitivity analysis determined prevalence of L. infantum infection in dogs to be most strongly affected by the sand fly associated parameters and the proportion of immigrant dogs already infected with L. infantum parasites., Conclusions: Establishing the model parameters with the highest sensitivity of average L. infantum infection prevalence in dogs to their variation helps motivate future data collection efforts focusing on these elements. Moreover, the proposed mechanistic modelling framework provides a foundation that can be expanded to explore spatial patterns of zoonotic VL in humans and to assess spatially targeted interventions.

The extensive use of pesticides in agricultural practices has been associated with human health problems and environmental contamination worldwide. Brazil is the largest consumer of pesticides in the world and Espírito Santo State stands out as the second Brazilian producer of coffee. However, there is no information about environmental impact of coffee producing at Itapemirim River Basin (IRB) region, Espírito Santo State, Brazil; hence a simple and quick method using open access softwares (AGROSCRE and ARAquá Web) to estimate surface entrainment and pesticide leaching potential was carried out. AGROSCRE evaluates the contamination risk of superficial and groundwater by Active Ingredients (AIs), using GOSS Method, GUS index and US EPA criteria, while ARAquá Web estimates AI concentrations in water resources, indicating their suitability based on water quality requirements for different uses. Regarding pesticides used in coffee plantations, there is 44.7% chance of surface water and 23.7% chance of groundwater contamination. Results showed that ametryne, cyproconazole, diuron, epoxiconazole, flutriafol, triadimenol and triazophos pose contamination risk to both surface water and groundwater in the IRB region. Of these, 10.5% of the total AIs are triazoles and fall under environmental classes II and III (Product Very/Dangerous to the Environment). The AIs ametryne, thiamethoxam, iprodione, flutriafol, triazophos, endosulfan, triadimenol, cyproconazole, diuron, pendimethalin, chlorpyrifos, copper II hydroxide, etion, epoxiconazole and paraquat dichloride, were found to be potentially toxic, presenting environmental concentrations ranging from 123.40 μg L -1 to 0.14 μg L -1 , which are higher than the safety standard for potable water (0.1 μg L -1 ). With respect to these AIs, chlorpyrifos, ethion and triazophos showed concentrations higher than EC 50 values for aquatic invertebrates and ametryne and diuron for algae. Thus, local residents and environment may be at high risk of pesticide exposure, when these AIs are used in coffee plantations next to surface water or groundwater., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Vaccinating monkeys against yellow fever (YF) has been a common practice in the beginning of the 17D vaccine development. Although it may seem strange at first sight, vaccinating monkeys as a public health strategy is, we think, feasible and theoretically could eliminate the infection among non-human primates, interrupting the virus circulation (or significantly reducing it) and therefore reducing the risk of spilling over to the human population. We propose a series of studies that could demonstrate (or not) the efficacy and feasibility of vaccinating non-human primates YF reservoirs living in green areas of urban centres to cut off or curb the virus circulation that recurrently spill over to the human population. Therefore, vaccinating monkeys in relatively small green areas of the urban centres is perhaps the ultimate solution for the Brazilian recurrent YF epizootics.