Search Results (215)

Natural lignocellulosic fibers (NLFs) replacing synthetic fibers have been used as reinforcement in polymer matrix composites. In this work, a lesser-known NLF endemic to the Amazon region, the envira fiber (Bocageopsis multiflora), was analyzed for its basic physical, thermochemical, morphological, and mechanical characteristics. In addition, epoxy matrix composites with 10, 20, 30, and 40 vol% of continuous and aligned envira fibers were evaluated by Fourier transform infrared spectroscopy (FTIR) and tensile tests. The results were statistically compared by ANOVA and Tukey’s test. The density found for the envira fiber was 0.23 g/cm³. The crystallinity index and microfibrilar angle obtained were 69.5% and 7.07°, respectively. Fiber thermal stability was found up to around 210 °C. FTIR confirmed the presence of functional groups characteristic of NLFs. Morphological analysis by SEM revealed that the envira fiber displayed fine bundles of fibrils and a rough surface along its length. The average strength value of the envira fiber was found to be 62 MPa. FTIR analysis of the composites confirmed the presence of the main constituents of the epoxy resin and NLFs. The tensile strength results indicated that the envira fiber addition increased the strength of the composites up to 40 vol%. The analysis of the fracture region revealed brittle aspects. These results indicate that envira fibers present potential reinforcement for polymer matrix composites and can be used in engineering applications, favored by their lightness and cost-effectiveness. Full article

The Amazon rainforest, a vital global carbon sink, is experiencing extensive forest loss due to environmental pressures, particularly from livestock production. While research on this topic has grown, a comprehensive synthesis is needed to map the intellectual landscape of this critical field and inform actionable policies. Unlike a systematic review, which synthesizes findings qualitatively, this analysis focuses on a quantitative overview of research trends, key authors, and collaborative networks regarding greenhouse gas emissions from livestock-driven deforestation in the Amazon from 2004 to 2024. Additionally, the study makes a thematic synthesis of reviewed literature providing overview on emissions, mitigation, and biodiversity impacts. The review, based on data from Scopus and Web of Science processed through Bibliometrix and VOSviewer software, reveals a growing and increasingly collaborative field, with research output showing significant growth post-2010, dominated by institutions in Brazil and the United States, with a conceptual focus that has shifted from basic deforestation metrics to sophisticated analyses of mitigation strategies and policy impacts. The findings highlight recurrent deforestation drivers, including export-oriented agriculture and weak land tenure, and demonstrate the effectiveness of specific mitigation options. Key mitigation strategies identified include silvopastoral systems with more than 30% tree cover, rotational grazing, and targeted pasture restoration, which can halve emissions within 5–7 years when combined with credit incentives and secure land tenure. The review underscores the evolution of research toward more policy-relevant and interdisciplinary approaches, but also highlights the need for more empirical validation and collaborative efforts to translate these findings into scalable climate solutions. Full article

Scorpionism is a growing public health concern in Brazil, with the Amazon region presenting the highest mortality rates but remaining understudied, especially regarding local scorpion venoms composition. This study presents the first comprehensive biochemical characterization of venoms from three Amazonian species—Tityus metuendus (TmetuV), Tityus silvestris (TsilvV), and Brotheas amazonicus (BamazV)—using an integrated approach combining Multi-Enzymatic Limited Digestion (MELD)-based bottom-up proteomics, high-resolution LC-MS/MS, chromatography, zymography, and enzymatic assays. Tityus serrulatus venom was included as a reference. Significant biochemical differences were observed: TsilvV was rich in 20–30 kDa proteins and showed strong metalloprotease activity; BamazV exhibited high molecular weight proteins and potent phospholipase A₂ (PLA₂) activity but lacked proteolytic and fibrinogenolytic activities; TmetuV showed the highest hyaluronidase activity and abundance of α-KTx neurotoxins. Zymography revealed a conserved ~45 kDa hyaluronidase in all species. Three novel components were partially characterized: BamazPLA₂ (Group III PLA₂), Tmetu1 (37-residue α-KTx), and TsilvMP_A (a metalloprotease homologous to antarease). This is the first application of MELD-based proteomics to Amazonian scorpion venoms, revealing molecular diversity and functional divergence within Tityus and Brotheas, emphasizing the need for region-specific antivenoms. These findings provide a foundation for future pharmacological studies and the discovery of bioactive peptides with therapeutic potential. Full article

Forest degradation, characterized by the gradual loss of the forest’s ecological and ecosystem functions, has been happening rapidly in the Amazon. Its main anthropogenic vectors are deforestation, forest fragmentation, selective logging, forest fires, and the edge effect. Impacts on the forest canopy and biomass can be estimated using satellite images and field data. The present study examines the dynamics of edges created annually by forest clearing and the effects of these edges considering the annual extent and loss of forest biomass between 2007 and 2023 in the municipality of Rorainópolis, located in the southern portion of the state of Roraima, in the far north of the Brazilian Amazon. We (i) delimited the edge areas created annually by deforestation between 2007 and 2023; (ii) tested the hypothesis of the existence of a spatial gradient for forest degradation using the increasing distance from the edge as a reference and the spectral behavior of three vegetation indices (NDVI, NBR, and NDWI) at the pixel level from average values of images from the Landsat-5/8 and Sentinel-2 satellites; and (iii) estimated the biomass exposed to deforestation and the edge effect and the consequent loss of biomass due to these processes. The loss of biomass in the study area due to deforestation totaled 17.1 × 10⁶ Mg in 2023, and the forest edge areas totaled 244.9 km², containing 10.5 × 10⁶ Mg of biomass. During 2023, we estimated a cumulative loss of 0.92 × 10⁶ Mg (8.73%). Analysis of the three vegetation indices showed that there is a gradient of forest degradation, characterized by an increase in the pixel index value from the edge to the interior of the forest. Forest degradation due to the edge effect is an important source of carbon emissions and should be included in national reports on greenhouse gas emissions. Full article

Deforestation and land-use changes lead to significant soil degradation and erosion, particularly in Amazonian ecosystems, due to the region’s climate and geology. This study characterizes soil quality using physical, chemical, and biological parameters across different land uses. It uses a soil quality index (SQI) based on a minimum data set (MDS), from 19 evaluated parameters. The land uses evaluated were cacao monoculture (CMC), agroforestry systems associated with fruit and timber species (FAFS and TAFS, respectively), and a secondary forest. The SQI was composed of six variables, bulk density (BD), soil organic matter (SOM), urease activity (UR), pH, dehydrogenase activity (DH), and leaf litter, which are considered relevant indicators that allow for an adequate evaluation of soil quality. According to the SQI assessment, FAFS has a moderate-quality rating (0.40), followed by secondary forest (0.35), TAFS (0.33), and CMC (0.30), the last three categorized as low-quality. The methods used are replicable and efficient for evaluating changes in soil properties based on different land uses and management systems in landscapes similar to those of the Ecuadorian Amazon. Also worth mentioning is the potential of agroforestry as a sustainable land-use strategy that can enhance above- and below-ground biodiversity and nutrient cycling. Therefore, implementing agroforestry practices can contribute to long-term soil conservation and the resilience of tropical ecosystems. Full article

Annona neoinsignis H. Rainer (Annonaceae) is a tree native to the Amazon rainforest. Its fruits are also suitable for human consumption in their natural state or are processed to make desserts. In this work, we characterized the chemical composition of the essential oil (EO) from the leaves of A. neoinsignis and evaluated its anti-liver-cancer potential via in vitro and in vivo approaches. Chemical composition analysis revealed β-elemene, (E)-caryophyllene, germacrene D, and germacrene B as the main constituents. The EO had IC₅₀ values ranging from 12.28 to 37.50 μg/mL for B16-F10 cells and MCF-7 cells, whereas an IC₅₀ value of >50 μg/mL was found for noncancerous MRC-5 cells. DNA fragmentation, YO-PRO-1 staining, and loss of mitochondrial transmembrane potential were detected in EO-treated HepG2 cells, indicating the induction of apoptosis. Significant in vivo growth inhibition of 53.7% was observed in mice bearing HepG2 cell xenografts treated with EO at a dosage of 40 mg/kg. These data suggest that EO from A. neoinsignis leaves is a drug source for liver cancer. Full article

The Amazon rainforest hosts a diverse array of forest types, including those where Brazil nut (Bertholletia excelsa) occurs, which plays a crucial ecological and economic role. The Brazil nut is the second most important non-timber forest product in the Amazon, a symbol of development and sustainable use in the region, promoting the conservation of the standing forest. Understanding the vertical structure of these forests is essential to assess their ecological complexity and inform sustainable management strategies. We used terrestrial laser scanning (TLS) to assess the vertical structure of Amazonian forests with the occurrence of Brazil nut (Bertholletia excelsa) at regional (Amazonas, Mato Grosso, Pará, and Amapá) and local scales (forest typologies in Amapá). TLS allowed high-resolution three-dimensional characterization of canopy layers, enabling the extraction of structural metrics such as canopy height, rugosity, and leaf area index (LAI). These metrics were analyzed to quantify the forest vertical complexity and compare structural variability across spatial scales. These findings demonstrate the utility of TLS as a precise tool for quantifying forest structure and highlight the importance of integrating structural data in conservation planning and forest monitoring initiatives involving B. excelsa. Full article

The Cerrado-Amazon Transition (CAT) in Brazil represents one of the most ecologically complex and dynamic tropical ecotones globally; however, it remains insufficiently characterized at high spatial resolution, primarily due to its intricate vegetation mosaics and the limited availability of reliable ground reference data. Accurate land cover maps are urgently needed to support conservation and sustainable land-use planning in this frontier region, especially for distinguishing critical vegetation types such as Amazon rainforest, Cerradão (dense woodland), and Savanna. In this study, we produce the first high-resolution land cover map of the CAT by integrating PlanetScope optical imagery, Sentinel-2 multispectral data, and Sentinel-1 SAR data within a U-net deep learning framework. This data fusion approach enables improved discrimination of ecologically similar vegetation types across heterogeneous landscapes. We systematically compare classification performance across single-sensor and fused datasets, demonstrating that multi-source fusion significantly outperforms single-source inputs. The highest overall accuracy was achieved using the fusion of PlanetScope, Sentinel-2, and Sentinel-1 (F1 = 0.85). Class-wise F1 scores for the best-performing model were 0.91 for Amazon Forest, 0.76 for Cerradão, and 0.76 for Savanna, indicating robust model performance in distinguishing ecologically important vegetation types. According to the best-performing model, 50.3% of the study area remains covered by natural vegetation. Cerradão, although ecologically important, covers only 8.4% of the landscape and appears highly fragmented, underscoring its vulnerability. These findings highlight the power of deep learning and multi-sensor integration for fine-scale land cover mapping in complex tropical ecotones and provide a critical spatial baseline for monitoring ecological changes in the CAT region. Full article

Malaria remains a public health issue across the world. Different methods have been analyzed to achieve this disease’s elimination, such as the vector control of Anopheles spp. Control strategies include the use of different classes of insecticides, although the accelerated evolution of vectors resistant to them makes the development of alternative control methods necessary. Therefore, entomopathogenic fungi have been considered to be promising biopesticides, given that they are safe for human beings and the environment. This study aimed to evaluate the entomopathogenic activity of fungi collected in the Amazon Rainforest against adult female Anopheles aquasalis mosquitoes. Females were exposed to four different species of fungi and observed daily to evaluate their survival rate. Also, fungi species’ behavior was analyzed through scanning electron microscopy (SEM). Those exposed to Trichoderma harzianum and Penicillium citrinum had their survival rate reduced. SEM confirmed the development of fungi on the mosquitoes after 48 h. The findings suggest that the entomopathogenic potential of the fungi used in this study should be considered, given the reduction in the survival rate of Anopheles aquasalis mosquitoes. Full article

Western written travel narratives are a byproduct of the privileging of vision as the primary means of knowledge production, an epistemology often imposed on indigenous peoples through colonial practices. In contrast, indigenous cultures in Brazil have long relied on listening as a central way of engaging with their environment. In the present essay, I examine how listening practices appear in the written accounts produced by members of three foreign river expeditions in Brazil from the 16th to the 20th century. I analyzed travel accounts from Gaspar de Carvajal’s Relación del Nuevo Descubrimiento del Famoso Río Grande (XVI century), Hercules Florence’s Voyage Fluvial du Tieté à l’Amazone (XIX), and Theodore Roosevelt’s In the Jungles of Brazil (XX). To explore what these travelers might have heard, I also collaborated with a sound designer to create a soundscape using actual recordings of local fauna and indigenous chants and music. The results show a variety of listening modes put into practice such as conquest-driven, scientific observation, contemplation, and hunting-focused and aesthetic appreciation. These narratives illustrate how European epistemologies reinforced Western dominance by shaping both colonial encounters and scientific approaches to Brazilian wilderness exploration. Full article

Trichomitus batrachorum is a species of trichomonad that has gained attention due to its ecological importance and potential interactions with various hosts, such as amphibians (anurans) and reptiles (lizards and chelonians), where it has been recorded in the gastrointestinal tract of these vertebrates, specifically in their feces. Molecular studies have placed this flagellated protist within the Metamonada clade. Unlike parabasalids that inhabit endothermic mammals in relatively stable temperature conditions, protists associated with ectothermic reptiles are subject to significant temperature fluctuations. The ability of T. batrachorum to thrive in the variable temperatures encountered by reptiles suggests that its parasitism may remain largely unaffected by climate change. In our study, we detected and characterized T. batrachorum from the liver tissue of the lizard species Ameiva ameiva, collected in Presidente Figueiredo Municipality, Amazonas State, Brazil. The identification of T. batrachorum was confirmed by cultivation technique, light microscopy, scanning electron microscopy and transmission electron microscopy for ultrastructural analyses, and sequencing the 5.8S rDNA (region ITS1- ITS2) and 18S rRNA (ribosomal RNA) genes. One potential interpretation for this finding is that the flagellates may have migrated from the intestine to the bile duct, ultimately reaching the liver. This is the first successful characterization of T. batrachorum in the liver of a lizard, and provides a solid foundation for further research to elucidate the potential pathogenicity of this flagellate and the role of A. ameiva in the epidemiology of parabasalids in other animal species. Full article

The growing interest in sustainable raw materials has led to a significant rise in demand for Amazonian vegetable oils, such as pracaxi (Pentaclethra macroloba (Willd.) Kuntze) and patauá (Oenocarpus bataua). This study examines the patterns of their usage in scientific publications between 2010 and 2023, emphasizing their potential in three key areas: food, cosmetics, and mineral processing. The methodology employed is the Systematic Literature Network Analysis (SLNA), which integrates Systematic Literature Review (SLR) with Bibliographic Network Analysis. We identified sixty-one scientific articles from the Scopus database, with 32 meeting the criteria for Bibliometric Analysis. Using the VOSviewer program (version 1.6.20), we performed a keyword co-occurrence analysis to create bibliometric maps. These maps provided a clear depiction of the main research areas and how they have evolved over time in relation to these oilseeds. To complement the descriptive analyses, the Bibliometrix R package (version 4.4.1) was used to extract bibliographic information. This methodology effectively identifies emerging research sectors and provides a solid foundation for future studies on the Amazon bioeconomy. Full article

The main goal of this study was to provide a new categorization of the different types of interactions between model-based system engineering (MBSE) and digital twins (DTs). To achieve this goal, an overview of the relationships between these two concepts was obtained based on a representative set of articles. The search identified 444 unique and valid records, of which 16 were selected for analysis based on article screening and eligibility assessments. The selected articles were then analyzed to identify the types of DT-MBSE relations and the area of the case study. As a result, the types of relationships were classified into two main categories: MBSE-based DTs and DTs that use MBSE system models. Finally, we present a case study of the Perception system, a system of systems designed to monitor and generate strategic assets through satellite data collection, further developing the capabilities established by the AlfaCrux satellite mission. Specifically, the case study focused on collecting data from a tower with micrometeorological instrumentation in the Brazilian Amazon Rainforest. The modeling was performed on the Capella software using the Arcadia method. In the case study, the system and the digital twin were designed in parallel based on a five-dimensional DT model. Full article

Acmella oleracea (L.) R.K. Jansen, also called jambù, is a medicinal and aromatic plant native to the Brazilian Amazon rainforest and phytochemically characterized by N-alkylamides with spilanthol as the main active compound. Jambù recently attracted the interest of many companies because of its wide range of pharmaceutical, nutraceutical, and cosmetic applications. In this context, it is desirable to identify eco-friendly cultivation methods that not only minimize the environmental footprint but also support the biosynthesis of the plant’s valuable bioactive compounds. The zero-discharge approach of aquaponics makes this growing system an eco-friendly and sustainable production strategy for crops. Thus, a greenhouse experiment was conducted on two jambù cultivars, i.e., cv ‘purple’ and cv ‘yellow’, grown in aquaponic and hydroponic systems. The objective was to compare their contents of N-alkylamides, their numbers of capitula, which are the main source of these bioactives, and their volatile profiles. The results highlighted differences between the two cultivars and among plants harvested at different periods. Interestingly, aquaponics yielded plants with a high N-alkylamide content, which was comparable to that obtained with hydroponics. Overall, this study highlighted the feasibility of adopting aquaponics to grow A. oleracea, paving the way for circular economy-based and sustainable agricultural practices. Full article

The estimation and correction of antenna patterns are essential for ensuring the relative radiometric quality of SAR images. Traditional methods for antenna pattern estimation rely on artificial calibrators or specific stable natural scenes like the Amazon rainforest, which are limited by cost, complexity, and geographic constraints, making them unsuitable for frequent imaging demands. Meanwhile, general natural scenes are imaged frequently using SAR systems, but their true scattering characteristics are unknown, posing a challenge for direct antenna pattern estimation. Therefore, it is considered to use the calibrated SAR to obtain the scattering characteristics of these general scenarios; that is, introducing the concept of cross-calibration. Accordingly, this paper proposes a novel method for estimating the SAR range antenna pattern based on cross-calibration. The method addresses three key challenges: (1) Identifying pseudo-invariant natural scenes suitable as reference targets through spatial uniformity and temporal stability assessments using standard deviation and amplitude correlation analyses; (2) Achieving pixel-level registration of heterogeneous SAR images with an iterative method despite radiometric imbalances; (3) Extracting stable power values by segmenting images and applying differential screening to minimize outlier effects. The proposed method is validated using Gaofen-3 SAR data and shows robust performance in bare soil, grassland, and forest scenarios. Comparing the results of the proposed method with the tropical forest-based calibration method, the maximum shape deviation between the range antenna patterns of the two methods is less than 0.2 dB. Full article