Anais da Academia Brasileira de Ciencias最新文献

Sweet basil is a tropical herbaceous plant valued for essential oil containing over 200 compounds. This study aimed to determine the optimal harvest time to harvest maximum essential oil and linalool yields in hot Southeast Anatolian conditions of Turkey, using two ecotypes, Dicle and Silbe, planted in Medicinal Plants Collection Garden, of Dicle University. The plants were harvested at five intervals of three hours duration from 06:00 to 18:00. Their dried leaves were hydrodistilled for extraction of essential oil, which was subjected to GC-MS analysis to determine the variance in chemical compounds composition. The results showed significant variations in essential oil contents, which fluctuated due to diurnal changes in temperature and humidity. The Dicle ecotype exhibited the highest essential oil contents after the 2nd cutting, The Silbe ecotype had the minimum essential oil after first cutting. The interaction between harvest times and ecotypes significantly affected oil yields. A biplot analysis revealed a two-dimensional PCA score (51.15% and 25.29%) for the Dicle ecotype, indicating a total variation rate of 76.44%. The study underscores the responsible factors in maximizing basil essential oil. It also indicated presence of 50-65% linalool and methyl chavicol in essential oil analyzed from the two O. basilicum ecotypes.

In this paper, we propose a new distribution based on a mixture of the unit-gamma distribution with a degenerate distribution at (c) (0 or1) or with a Bernoulli distribution. This novel approach is particularlyuseful for addressing excess zeros and/or ones in the data with limitedsupport in ( 0 , 1 ) .Our approach considers Bayesian parameter estimation, residual, and influence analysis, as well as model comparison methods. We illustratethe theory by applying it to a real-world problem, with all posteriorquantities obtained using Markov Chain Monte Carlo (MCMC) methods.

The steady-state convection-diffusion equation is part of the mathematical model for transport phenomena. Its exact solution may present boundary layers when convection is dominant. In these cases, numerical solutions of the second-order centered finite difference present spurious oscillations, and stabilized methods may present the smearing effect. Here new h 1 and h 2 vector norms and seminorms are proposed as analogs to the H 1 and H 2 norms used in the finite element framework, which allow defining new errors for the solutions and their derivatives obtained by the finite difference method. In addition, new w l 2 , w h 1 and w h 2 weighted norms and seminorms are introduced, allowing to observe convergences of the schemes similar to what should be expected theoretically. These norms and seminorms and their weighted versions are valid for uniform and non-uniform meshes. Furthermore, exact solutions with boundary layers are proposed as benchmarks together with the errors in the new vector norms of two classical finite difference schemes: centered and upwind. Numerical results indicate that a mesh that guarantees an acceptable approximation for the solution u does not guarantee an acceptable approximation for the derivatives of u . For this reason non-uniform meshes and new schemes will be analyzed in future articles.

The high phenotypic and genotypic variabilities increases the chances of success in selection of genotypes based on efficiencies for using the available water resources. The objective was to evaluate the productive efficiency of 27 genotypes of Coffea canephora regarding the amount of water made available over the first four reproductive cycles. The experiment followed a split plot scheme, with 27 genotypes and four reproductive cycles, in a randomized block design. Genotypes 108 and 201 stand out for the highest productive efficiencies, using, on average, 2.85 liters of water for each gram of coffee. Less productive genotypes, as 203 and 307, present the lowest efficiencies, using up to 11.24 liters per gram of coffee. Efficient genotypes can save up to 75% of the water required per gram of coffee produced. Genotype 102 have not shown a significant variation in its productive efficiency throughout the harvests, electing it as the most stable among the genotypes. Studying the behavior of genotypes of Conilon coffee for productive efficiency emerges as a tool that can contribute to the selection of genotypes in specific conditions of water use, which can assist in the rational use and conservation of water resources.

Reservoirs are important for water resource management, but traditional bathymetric surveys are costly and have limited capacity for continuous monitoring. This study investigates using Sentinel-2A imagery to estimate bathymetry in Brazilian semi-arid reservoirs. Field data were collected at two reservoirs using an echosounder and georeferenced with RTK GPS. Sentinel-2A Level-2A images were processed in Google Earth Engine to calculate the Normalized Difference Water Index (NDWI) and generate temporal compositions (monthly, quarterly, semi-annual, and annual). Nonlinear regression models (exponential and potential) and machine learning algorithms (Artificial Neural Networks, Support Vector Machines, and Random Forest) were applied to estimate bathymetry. Results demonstrated that models using quarterly temporal compositions achieved the highest accuracy, with the Random Forest (RF) algorithm and nonlinear models based on the Near-Infrared (NIR) band performing particularly well. The RF algorithm yielded a Camargo & Sentelhas performance coefficient (c) of 0.68 for Cachoeira Reservoir, while the NIR-based model achieved a coefficient of 0.85 for Jazigo Reservoir. These findings highlight the potential of remote sensing as a cost-effective and efficient alternative for continuous bathymetric monitoring in semi-arid regions. The study underscores the importance of temporal compositions and model selection, providing valuable insights for improving water resource management and decision-making.

This study characterizes the Fazenda Campos Novos (FCN) Sambaqui, a prehistoric shell mound site in Cabo Frio, Brazil. By analyzing the physical, geochemical, and paleoenvironmental aspects of the sambaqui, we aim to understand the environmental conditions associated with the sediments within the shell midden. Methods employed included sediment grain size analysis, X-ray fluorescence, wet chemical characterization, magnetic susceptibility analysis, and radiocarbon dating to provide chronological context. Granulometric data revealed a predominantly sandy loam texture and high magnetic susceptibility values, indicative of human-induced heating events. Chemical analyses revealed elevated levels of organic matter, phosphorus, strontium, and other elements, suggesting significant anthropic influence and resource utilization by prehistoric inhabitants. The presence of marine shells and sandy sediments indicates a coastal depositional environment. Radiocarbon dating placed the sambaqui's age between 3230 and 3350 years BP, aligning with other regional archaeological sites. Paleoenvironmental reconstructions suggest that the FCN Sambaqui formed during a Holocene marine transgression. These findings enhance our understanding of the cultural practices, environmental conditions, and human-environment interactions associated with the FCN Sambaqui, providing a valuable record of prehistoric life and informing future research on coastal archaeology and paleoenvironmental studies.

Microbial resistance is a product of both continuous evolution and un-checked antimicrobial usage and accelerates the demands for the development of new and effective antimicrobials. Lamiaceae and Verbenaceae are widely used empirically in folk medicine and their antimicrobial potential is being explored worldwide. The Caatinga has a higher number of Lamiaceae and Verbenaceae species, although less than 10% of this biome is protected by conservation units. This study aimed to perform a systematic review and technological prospection of antimicrobial studies of Lamiaceae and Verbenaceae from the Caatinga. Two reviewers analyzed the literature searches in six electronic databases using PRISMA guidelines. Patents were searched through INPI, Espacenet, and Patentscope. According to an in-depth analysis of the 42 studies and five patents, these plants show promising antibacterial and antifungal properties through essential oils, crude extracts and their fractions. Potential technological applications of these plants include the development of new antibacterial agents, food preservation and quality control solutions, and innovative dental materials. We believe that this review will provide researchers with knowledge of antimicrobial and technological strategies, as well as data on the potential use of these families to support future decisions regarding the conservation of the Caatinga.

Plastic waste affects wildlife globally, yet reptiles are often overlooked in studies. On December 23, 2023, an adult Drymarchon corais was captured in Presidente Figueiredo, Amazonas, Brazil. During handling, the snake regurgitated prey items along with plastic wrappers. This case represents the first record of plastic ingestion by a snake in the Amazon. It demonstrates how improperly discarded waste infiltrates food webs, likely through prey that previously ingested plastic or accidental consumption during foraging. The study highlights the urgent need for effective waste management policies and further research to understand the broader impacts of plastic pollution on Amazonian biodiversity.

Solid oxide fuel cells can generate electrical energy with electrical efficiency exceeding 50% and reduce pollutant emissions, particularly, when the fuel is hydrogen. They have numerous applications, such as stationary generation, aircraft, and hybrid plants producing hydrogen and electricity. This work uses a thermodynamics lumped model to obtain the voltage versus current density of an SOFC, and distinctively of other authors also use heuristic and deterministic optimization algorithms to determine the main operation variables to achieve maximum power for a single cell. Moreover, it also has a detailed discussion of the transport of each overpotential, particularly the concentration overpotential, along with a comprehensive set of equations for its calculation. It also connects the physical and chemical phenomena to the main modeling variables. Unlike other reviewed studies, the Butler-Volmer equation is solved using an implicit solution. The results demonstrate that higher pressures and temperatures improve power output, with both heuristic and deterministic algorithms producing similar results for maximum power. The model allows the SOFC to operate efficiently within a hybrid system and serves as a method for estimating key operating variables while assessing the influence of physical and chemical parameters on performance.

Odonata, comprising the suborders Anisoptera and Zygoptera, are important bioindicators of aquatic ecosystem health due to their sensitivity to environmental changes. We assessed the effects of environmental variables and geographic distance on larval Odonata assemblages in 25 natural lakes of the Brazilian savannah, in northern Roraima. We focused on Anisoptera, characterized by strong flight abilities and greater dispersal capacity, and Zygoptera, which are more sensitive to local environmental variation due to their limited dispersal capacity. We collected 9,578 larvae of 12 Anisoptera species and 2,884 larvae of eight Zygoptera species. Larval Odonata assemblages are influenced by abiotic variables rather than geographic distance, and richness was positively associated pH. Assemblage composition and abundance were affected by key abiotic conditions. Odonata abundance was positively correlated with oxygen and temperature, but negatively correlated with phosphate. Anisoptera abundance increased with dissolved oxygen and geographic distance, but decreased with phosphate and electrical conductivity. Meanwhile, Zygoptera abundance showed a positive correlation with conductivity and temperature but a negative relationship with geographic distance, pH, and phosphate. Additionally, pH influenced assemblage composition, positively affecting Anisoptera but negatively Zygoptera. Our results provide valuable insights into conservation planning and environmental policies aimed at preserving aquatic biodiversity in the region.