Anais da Academia Brasileira de Ciencias最新文献

Lipases are enzymes that have an important role in the industry for their wide use, giving rise to a great interest in industrial bioprocesses due to their versatility. One of the applications is the enzymatic hydrolysis of waste oils. This work consists of evaluating the production of lipases using several concentrations of residual frying oil (RFO) and different pHs, through ANOVA analysis. The production of free fatty acids was carried out by hydrolysis of RFO using noncommercial lipases produced in the previous step. The production of lipase enzymes was favored at pH 2.0, with an oil concentration of 1.5% (v/v) for a period of 24 hours, resulting in an enzyme activity of 141.90 U. mL-1 . The highest result of enzymatic hydrolysis of RFO was 20.70% in 40 minutes. This conversion was favored by increasing the concentration of the enzymatic extract. In this study, it was possible to obtain free fatty acids (FFAs) using a noncommercial enzyme and waste oil as an environmentally correct and low-cost alternative.

Regional sea level rise varies from the global average and is influenced by climate variability. We studied sea level anomalies in southern Brazil from 1993 to 2022, finding increasing trend from 1993 to 2022. We used oceanic and atmospheric dynamics to understand the rapid sea level rise. Positive trends in the Southern Annular Mode and the South Atlantic Ocean subtropical gyre intensified wind stress curl and Ekman transport. If global warming continues and the Southern Annular Mode remains in a positive trend, sea level rise in southern Brazil is likely to persist and increase risks for the population in this low-lying coastal area.

Night-blooming cacti, primarily pollinated by bats and hawkmoths, also attract beetles seeking food and safe shelter for mating and brooding their offspring. The influence of flower density on beetle visitation rates remains unclear, with responses varying by species and environmental factors. In the Caatinga Seasonally Dry Tropical Forest, we studied the flower occupancy distribution of two beetle species, Cyclocephala paraguayensis and Nitops aff. pilosocerei, in Pilosocereus pachycladus cacti. Our findings indicate that both beetle species act as commensals with minimal impact on effective pollination. They forage for nectar and pollen without causing damage to pistils or ovaries. N. aff. pilosocerei was more abundant than C. paraguayensis, and their distributions significantly differed, with N. aff. pilosocerei displaying a more uniform spread. Instances of both species occupying the same flower were more frequent than exclusive occupation. Nitops aff. pilosocerei abundance exhibited spatial autocorrelation. Flower height and beetle species influenced the total number of beetles within flowers. Future studies should explore the impact of cactus flower distribution on beetle abundance with other species, conduct selective pollination experiments to determine their role as pollinators, and investigate how flower-beetle interaction systems are affected by flower and individual distribution in processes like florivory and pollination.

The transmission gearbox of military helicopters, such as the H225M, experiences intense dynamic loads, leading to the detachment of ferromagnetic particles, often due to wear or fatigue. This poses safety risks, as excessive particle detachment demands stringent maintenance. To address this, the study applies machine learning algorithms to predict particle detachment using data from the Flight Data Recorder and Health and Usage Monitoring System. The approach aims to mitigate operational challenges faced by the Brazilian H225M fleet while considering aviation safety criteria and the pre-processing needs for an effective machine learning application.

The Southern Ocean influences the planet's biogeochemical cycles. Marine microorganisms are important in this scenario, being the main biological agents in the cycling of many elements. The Archaea domain is widely distributed in the oceans, and its presence in Antarctica is acknowledged. In this context, this work aimed to analyze the diversity and distribution of archaea according to environmental parameters in the waters surrounding the north of the Antarctic Peninsula. For environmental characterization studies, surface and bottom data were used for the ten monitoring stations of expeditions that took place in the summer of 2014 and 2015. The sequencing of the 16S rRNA gene was performed on the Illumina HiSeq platform, using the SILVA v138 database. The results revealed the presence of three main water bodies: Antarctic Surface Water, Shelf Waters, and modified Circumpolar Deep Water. Deep waters had higher diversity than surface waters, and the dominant groups were Nitrososphaeria and MGII. In the study region, the main factor responsible for the differences in the ecosystems was the presence of distinct water masses and the stratification of the water column. We argue that it is essential to consider water mass dynamics to study the microbial landscape of the Southern Ocean.

Pantanal fires have a significant impact on the environment. Anthropogenic emissions of residual gases have changed the tropospheric composition in this region due to burning. This study aims to analyze the spatial patterns of atmospheric pollutants (including carbon monoxide (CO), nitrogen dioxide (NO2), black carbon (BC), organic carbon (OC) and sulfur dioxide (SO2) and aerosol optical depth, along with fire outbreaks across the Pantanal biome from 2016 to 2021. The data collected is based on remote sensing data. The fire outbreaks peaked pollutant concentrations reached their highest between June to November, particularly during the drier months of August to October. This increase was even greater during the last three years (2019-2021), especially in 2020, when the average CO, NO2, SO2, BC, and OC concentrations increased by 29%, 31%, 50%, 52%, and 50%, respectively. The rainfall values do not justify the increase in the number of fire outbreaks between 2019 and 2021, indicating that the rise is likely due to increased burning. In 2021, the average monthly rainfall was 48% greater than that in 2016-2020 but it had the highest FRP value and the second highest fire outbreak number and pollutant concentration. The 2020 year experienced a record number of fire outbreaks and the highest levels of pollutants in the atmosphere in the region for this period.

Predicting biomass of arborescent individuals on sample plots using allometric models is an essential step in the computation of design-based forest biomass estimates. Nonetheless, there are few models for species with different growth forms, such as tree ferns. This study, therefore, sought to construct models to predict {aboveground.

The research aimed to evaluate the shrimp waste meal (SWM1) in the diet of European quails in the production phase. A metabolism trial was performed with 96 quails of 28 days of age distributed in a completely randomized design with three treatments (reference diet and two test diets in which SWM replaced 20% and 40% of the reference diet) and four replications of eight birds. There was no difference in metabolizable energy values. In the performance trial 200 quails of 28 weeks of age were distributed in a completely randomized design with four treatments (0, 50 100 and 150 g/kg of inclusion of SWM) and five replications of ten birds. There was reduction in the nitrogen metabolization coefficient with the inclusion of 150 g/kg SWM. The feed intake, production and egg mass worsened with 150 g/kg inclusion. The inclusion of SWM at all levels reduced the values of specific gravity and Hugh units, and the level 150 g/kg promoted reduction in shell percentage and shell thickness. It was concluded that the metabolizable energy of SWM is 2,377 MJ/kg and that the inclusion of SWM in the diet of quails in production can be up to 100 g/kg.