Eastern Amazon Region Research Articles

CHEMICAL ATTRIBUTES AND SOIL CARBON AND NITROGEN STOCKS IN PASTURES IN THE MARANHÃO AMAZON

In the eastern Amazon region, converting forests into pastureland is a common practice that quickly leads to the degradation of these areas. This study aimed to evaluate the influence of different land uses in different evaluation periods on the chemical attributes, total contents, and carbon and nitrogen stocks of the soil in the Maranhão Amazon. The land use systems analyzed were: perennial pasture (PP), recovered pasture (RP), and secondary forest (SF). Trenches were opened in 2013 and 2019 in each use system in the 0.0-0.20 m and 0.20-0.40 m soil layers. The soil chemical attributes (pH, P, K, Ca, and Mg) and C and N contents and stocks were assessed. PP in the surface layer showed superior results compared to RP and SF, while the opposite behavior occurred in the subsurface. The chemical attributes of the soil decreased over the years evaluated, regardless of the layer and area. The chemical attributes of the soil, as well as the C and N contents and stocks, changed depending on the land use, layer, and year of sampling.

Individual tree mortality: Risks of climate change in the eastern Brazilian Amazon region

The mortality of trees in humid tropical forests plays a fundamental role in understanding forest development, particularly after disturbances such as those caused by logging and extreme weather events. The aim of this study was to evaluate estimates of individual tree mortality following Reduced Impact Logging (RIL) in the Eastern Brazilian Amazon at biennial intervals from 2005 to 2012. RIL is based on operations planning, personnel training, and investments in forest management, and harvesting through RIL must: (a) minimize environmental damage, (b) diminish operation cost by increasing work efficiency, and (c) reduce operational waste. A mortality model was constructed based on the estimation of three distance-independent competition-indices (DII) and five models for predicting the probability of individual tree mortality. The Kolmogorov-Smirnov statistical test was used to determine the most representative model, from which a Neural Network Autoregressive (NNAR) model was constructed to forecast mortality after RIL. Mortality data was correlated with the El Niño–Southern Oscillation (ENSO) and climate (Rainfall, Maximum, Minimum, and Average air temperature). The tested models showed similar and accurate estimates with R2 exceeding 0.90, although underestimation and overestimation trends were observed. The NNAR satisfactorily represented species mortality over the simulated years. The period from 2012 to 2014 was characterized by a Neutral and Weak El Niño event, and exhibited the highest mortality value for a 25 cm DBH (diameter at breast height), the smallest DBH class measured in this study. In the correlation matrix analysis, maximum air temperature showed the highest positive correlation with trees mortality. Despite the challenges in estimating individual tree mortality in tropical forests after selective logging, accurate estimates were achieved using traditional regression techniques and NNAR. These results can support technical and silvicultural decisions regarding forest management in the Eastern Amazon region of Brazil.

Forest biomass recovery twenty-four years after conventional and reduced-impact logging in Eastern Amazon

Given the mounting global concerns about mitigating climate change and curbing greenhouse gas emissions, it becomes increasingly crucial to comprehend the effects of logging techniques on biomass dynamics in tropical forests. This understanding is essential for fostering greater carbon retention and sequestration, aligning with the objectives of initiatives like REDD+ (Reducing Emissions from Deforestation and forest Degradation plus sustainable forest management and the conservation and enhancement of forest carbon stocks) and other conservation goals. In this context, this study investigated the effects of two wood harvesting methods, reduced-impact logging (RIL) and conventional logging (CL), on above-ground biomass (AGB) recovery rates 24 years after harvesting. The experimental design was based on three treatments: RIL, CL, and an unlogged control plot, situated in the municipality of Paragominas, State of Pará, in the Eastern Amazon region of Brazil. All trees with diameter at breast height (DBH) ≥25 cm, as well as all trees of commercial species with a DBH ≥10 cm, were monitored in a 24.5 ha plot within each treatment. Additionally, a 5.25 ha subplot within each treatment was designated for the monitoring of all trees with DBH ≥10 cm. The biomass data were generated from 11 measurements carried out from 1993 to 2017 (24-year period). Pre-logging AGB stocks were estimated at 181 Mg ha-1 in the RIL plot, 187 Mg ha-1 in the CL plot, and 174 Mg ha-1 in the control plot. One year after logging, AGB decreased by 19 % under RIL and 30 % under CL, while the control forest remained unchanged. By 13 years after harvest, the RIL plot achieved 102 % AGB recovery, while the CL plot recovered 86 % of the original pre-harvest stock. Over the 24-year post-logging period, AGB stocks recovered to 128 % in the RIL plot compared to only 90 % in the CL plot, while the control forest maintained 93 % of its original stock. The average annual ABG increment rates were 3.56 Mg ha-1 year-1 after RIL and 2.33 Mg ha-1 year-1 after CL. Our findings demonstrate that implementing RIL is a more effective strategy for maintaining post-logging AGB stocks and accelerating AGB recovery rates, serving as a significant mitigation measure against climate change.

Geophysical surveys at Formoso underwater archaeological stilt village in the eastern Amazon region, Brazil

Archaeological evidence of pre-colonial indigenous villages are scarce in the Amazon region. Normally, wood decomposes quickly in the ground. However, in the case of stilt houses, the archaeological materials can be well preserved underwater or buried in sediments below waterbodies. The main objective of this work is to advance the understanding about the archaeological stilt village at the Formoso Lake in the Maranhão wetland, eastern Brazilian Amazon. We applied Ground Penetrating Radar (GPR) and Side Scan Sonar (SSS) for this underwater archaeological investigation. The GPR results allowed us to map the lakebed and detect diffraction hyperbolas in the water column, which can be related to wood stilts. The SSS results also helped image the lakebed and identify stilts with a higher spatial coverage compared to GPR. The combination of these two non-invasive geophysical methods allowed us to detect stilts beyond the area found in previous studies. These findings can guide the search and collection of new archaeological materials and, therefore, contribute to preserving this unique cultural heritage.

Evaluation of the Bioactive Compounds of Apis mellifera Honey Obtained from the Açai (Euterpe oleracea) Floral Nectar.

The biodiversity of Brazil provides an excellent climate and favorable pollination conditions for Apis mellifera L., especially in the Eastern Amazon region, which boasts vast floral wealth, including an abundance of açaí (Euterpe oleracea) flowers and fruits. In the present study, seven types of honey were evaluated: three containing floral nectar from açaí (Açaí honey) collected in the Eastern Amazon region (Açaí honey from Breu Branco (AH1 and AH2) and Açaí honey from Santa Maria (AH3), both from the state of Pará, Brazil) and four honeys from different regions of Brazil (Aroeira honey from Minas Gerais, Cipó-Uva honey from Distrito Federal, Mangue honey from Pará, and Timbó honey from Rio Grande do Sul). The characteristics of these honeys were evaluated by examining their physicochemical properties, melissopalynological aspects, color, antioxidant potential, and their constituent compounds, which were confirmed through GC-MS analysis. Açaí floral nectar honeys presented physicochemical results similar to those of other honeys, aligning with Brazilian legislation norms, but differed in their high values of free acidity, apparent sugars, and lower reducing sugars, which are directly related to their botanical origin. These differences correlate with unique flavor and distinct aroma characteristics. Melissopalynological analysis confirmed the botanical origin of the honeys containing açaí floral nectar, which had a color range from amber to dark amber. The three açaí honeys demonstrated high antioxidant capacity and superior flavonoid and polyphenol content compared to other honeys, particularly the açaí honey from Breu Branco (AH1), which had four times the content to combat free radicals compared to the honey with the highest potential (Aroeira honey). GC-MS analysis confirmed the presence of antioxidant properties as well as potential anti-inflammatory, antibacterial, antimicrobial, and antitumor capabilities in açaí honeys, which have not yet been fully studied.

Human outbreaks of a novel reassortant Oropouche virus in the Brazilian Amazon region.

The Brazilian western Amazon is experiencing its largest laboratory-confirmed Oropouche virus (OROV) outbreak, with more than 6,300 reported cases between 2022 and 2024. Here, we sequenced and analyzed 382 OROV genomes from human samples collected in Amazonas, Acre, Rondônia, and Roraima states, between August 2022 and February 2024, to uncover the origin and genetic evolution of OROV in the current outbreak. Genomic analyses revealed that the upsurge of OROV cases in the Brazilian Amazon coincides with spread of a novel reassortant lineage containing the M segment of viruses detected in the eastern Amazon region (2009-2018) and the L and S segments of viruses detected in Peru, Colombia, and Ecuador (2008-2021). The novel reassortant likely emerged in the Amazonas state between 2010 and 2014 and spread through long-range dispersion events during the second half of the 2010s. Phylodynamics reconstructions showed that the current OROV spread was mainly driven by short-range (< 2 km) movements consistent with the flight range of vectors. Nevertheless, a substantial proportion (22%) of long-range (> 10 km) OROV migrations were also detected, consistent with viral dispersion by humans. Our data provides a view of the unprecedented spread and evolution of OROV in Brazilian western Amazon region.

The Challenges of Naval Electromobility in Amazônia

Introduction: This study aims to assess the feasibility of replacing a diesel-powered tourist boat with a Solar Electric Hybrid Catamaran with a capacity for fifty people to promote sustainable tourism in the Amazon, specifically in the Belém-Pará region. The initiative seeks to take advantage of the opportunity presented by COP 2030 to innovate in the waterway transportation matrix through renewable energy sources. The research is based on sustainability concepts, the environmental impacts of using fossil fuels and the advantages of using solar energy for waterway transportation. The methodology includes a comparative analysis of diesel-powered vessels' operational and environmental costs and a Hybrid Electric system based on data compiled from a master's thesis. The expected results include identifying significant benefits in terms of reduced carbon emissions. The discussion will address the challenges faced in implementation, such as the initial investment costs, the maintenance of the new technologies, and the adaptation of operators and tourists to the latest transportation conditions. The implications of this research are vast; it can serve as an incentive for energy transition in the river transportation sector. Furthermore, this research pioneers the proposal of replacing diesel-powered tourist boats with solar electric hybrid models in the Amazon region. The study adds value by presenting a practical and sustainable solution to the environmental challenges the tourism sector faces, in line with the global sustainability goals set by COP 2030. Objective: This research outlines the importance and potential of naval electric mobility in the Eastern Amazon region, highlighting its relevance within COP 2030 and the SDGs for promoting ecotourism for the Amazon region. Theoretical Framework: The research is based on sustainability concepts, the environmental impacts of using fossil fuels, and the advantages of using solar energy for water transportation. In addition, previous experiences of implementing similar technologies in other regions and the potential for replicability in the Amazon are considered, focusing on environmental conservation and economic development. Method: This research is a compilation of the master's thesis entitled "Waterway electric propulsion technologies: conceptual design of a hybrid vessel with a focus on meeting environmental, social and Governance (ESG) practices," where the study was carried out in the municipality of Belém, Pará in the year 2023. Results and Discussion: The expected results include identifying significant benefits in terms of reduced carbon emissions, lower noise pollution and improved air quality. The discussion will address the challenges faced in implementation, such as initial investment costs, maintaining the new technologies and adapting operators and tourists to the new transportation conditions. Social acceptance and the potential for a positive impact on local tourism will also be assessed. Research Implications: This research has vast implications, ranging from contributing to climate change mitigation to promoting more sustainable tourism practices in the Amazon. Adopting the Solar Electric Hybrid Catamaran can serve as a model for other areas with similar geographical characteristics, encouraging public policies aimed at using renewable energies in the transportation sector. Originality/Value: This research pioneers the proposal of the replacement of diesel-powered tourist boats with a solar electric hybrid model in the Amazon region. The study adds value by presenting a practical and sustainable solution to the environmental challenges faced by the tourism sector, which is in line with the global sustainability goals set by COP 2030.

Impact of Production Systems on the Levels of Vitamin E, β-Carotene, and Cholesterol in the Liver of Cattle Raised in the Eastern Amazon.

The nutritional composition of bovine liver, particularly in terms of vitamins E, β-carotene, and cholesterol concentration, is significantly influenced by the cattle-rearing system and diet. This study aimed to elucidate the impact of four predominant cattle-rearing systems in the Eastern Amazon region on the vitamin E, β-carotene content, and cholesterol levels in bovine liver during the rainy season. Liver-tissue samples were collected from 48 cattle, with twelve specimens representing each rearing system. The systems encompassed two native pastures located in flood-prone areas, cultivated pastures on upland terrain and a confinement-rearing system. Our findings indicate that, when considering all rearing systems collectively, there were no significant differences in the levels of vitamins and cholesterol in the liver tissues (p > 0.05). However, a marked disparity in cholesterol levels emerged when comparing intensive rearing systems to extensive ones, with the former demonstrating notably higher concentrations (p = 0.01). Additionally, the intensive rearing system was associated with elevated levels of β-carotene (p < 0.01), α-tocopherol (p = 0.01), and β-tocopherol (p = 0.01) relative to the extensive systems. No significant variations were observed amongst the different extensive systems (p > 0.05). These results suggest that, while all rearing systems yielded liver tissues with typical concentrations of vitamins and cholesterol, the intensive rearing system led to a higher accumulation of certain vitamin compounds. This study highlights the substantial nutritional implications of different cattle-rearing systems in the Eastern Amazon and provides valuable insights for developing dietary strategies to optimize the nutritional quality of bovine liver. Therefore, the generated results are groundbreaking in the Eastern Amazon, Brazil, and inspire the development of new research projects to address other demands in this field and achieve additional outcomes.

Methodological Approach for Assessing Impacts and Recovery of Selectively Logged Forests in Tropical Forests

Ecosystem structure and function depends on the local and regional species pools, climate, geology, and type and frequency of disturbances. Tropical rain forests have long been growing in relatively stable climatic conditions and little disturbances until recent decades, when large-scale of land conversion into croplands and forest impacts by selective logging activities and forest fires have been more frequently observed. Selective logging causes forest degradation, which requires a rigorous monitoring system to control and mitigate forest impacts and recovery. Overtime forest disturbances and recovery can be estimated by using vegetation indices derived from remotely sensed data that enable us to distinguish disturbed from undisturbed forests and estimate the degree of those disturbances. This study aimed to assess the suitability of the Modified Soil Adjusted Vegetation Index (MSAVI) to detect selectively logged forests and estimate the forest recovery structure in a study site in the state of Pará, Eastern Amazon region. We retrieved the MSAVI from Landsat imagery to assess forest impacts by selective logging before and after logging. The estimated MSAVI index before and after logging activities were significantly different and enabled us to distinguish forest recovery structures after selective logging in the study site. Our methodological approach can be used to monitor selective logging activities and support planning of Sustainable Forest Management in tropical regions.

Eryngium foetidum Reported as a New Host of Meloidogyne enterolobii in the State of Pará, in the Eastern Amazon Region, Brazil

Amazon chicory (Eryngium foetidum L. [Apiaceae]), also known as culantro, is native to Tropical America and the West Indies. It belongs to the unconventional food plants (UFPs) group, and in addition to be consumed as a spice herb, it possesses a wide range of ethnomedicinal uses (Paul et al. 2011). In 2019, in the eastern Amazon region of Brazil, state of Pará, producers of E. foetidum in the municipality of Castanhal (01°15'363” S 047°10'232” W) reported the occurrence of underdeveloped plants with leaf yellowing and a large number of galls in the root system, which are typical symptoms of root-knotting nematode. Soil and root samples were collected and sent to the Nematology Laboratory (LabNema) located at the Faculty of Agrarian and Veterinary Sciences, UNESP, Jaboticabal, São Paulo, Brazil. A total of 46 second-stage juveniles (J2s) were extracted per 100 cm3 of soil, and a total of 460 eggs and J2s Meloidogyne spp. were found per gram of root. Morphological and molecular techniques were used to identify the species. The analysis of the perineal patter of ten females revealed thin striations in an oval shape with a high and semi-trapezoidal dorsal arch. No striations were observed in the perivulvar region. The labial region of the ten males analyzed exhibited a non-prominent labial disc, fused and slightly recessed submedian lips, with no apparent annulations. The morphological characteristics observed in the adults were consistent with those originally described for Meloidogyne enterolobii (Yang; Eisenback, 1983), confirming the species purity of the recovered population. Three individual nematodes had their 18S rDNA region sequenced (Holterman et al. 2006) which showed an average identity of 99.7% with other sequences of M. enterolobii available in the GenBank database. A Bayesian phylogenetic tree was constructed, providing insights into the specific relationship of M. enterolobii recovered from E. foetidum with other related nematodes. Each of the three sequenced nematodes represented a unique haplotype, resulting in their separation into distinct clades. Moreover, the obtained sequences presented polymorphisms that differed from the M. enterolobii sequences already available in the database, highlighting the genetic diversity of this species in relation to its original host (Silva et al. 2021). The species M. enterolobii was also confirmed using species-specific primers for M. incognita, M. javanica, and M. enterolobii (Zijlstra et al. 2000; Tigano et al. 2010). To confirm the pathogenicity of M. enterolobii on E. foetidum, a modified Koch Postulate was conducted. Six seedlings of E. foetidum were transplanted individually to 10-liter pots containing autoclaved soil. Each pot was then inoculated with 5 mL of a suspension containing 3,000 eggs and J2s from the original population of M. enterolobii obtained from E. foetidum. After 90 days, the inoculated plants exhibited root galls with a plentiful egg mass, in contrast to the healthy non-inoculated plants. The average number of M. enterolobii nematodes recovered from the roots of the inoculated plants was 42,040 eggs and J2s, resulting in a reproduction factor (RF) of 14.0. The importance of reporting the occurrence of M. enterolobii in E. foetidum is due to the fact that this plant species is cultivated in a crop rotation system with other vegetables such as lettuce and coriander, which are also hosts of M. enterolobii. Consequently, different crop rotation strategies and control alternatives need to be considered in areas where E. foetidum is grown. This is the first report of E. foetidum serving as a host for the root-knot nematode M. enterolobii worldwide.

Prevalence and circulant genotypes of Chlamydia trachomatis in university women from cities in the Brazilian Amazon.

Approximately 80% of infected women infected by Chlamydia trachomatis are asymptomatic, although this infection can lead to serious complications in the female reproductive tract. Few data on Chlamydia infection and genotypes are available in Amazonian communities. To describe the prevalence of and associated factors and to identify the genotypes of sexual C. trachomatis infection in female university students in different urban centers (capital and interiors) in the Brazilian state of Pará, in the eastern Amazon region. A cross-sectional study was performed among young women attending public universities in four different urban centers in the eastern Amazon region. They were invited to participate in the studt and cervical secretions were collected for molecular diagnosis of C. trachomatis. We utilized amplification of the ompA gene by nested PCR. Positive samples were genotyped by nucleotide sequencing. Study participants completed a questionnaire on social, epidemiological, and reproductive health variables. A Qui-square and Binominal regression test were used to evaluate the degree of association of these variables with the infection. A total of 686 female students was included in the study. The overall prevalence of C. trachomatis was 11.2% (77/686). The prevalence of this infection was higher in interiors (15.2% vs 9.5%/ p: 0.0443). Female university students who do not have a sexual partner (11.8%/p <0.008), who do not use a condom in their sexual relations (17.8%/p <0.0001) and who reported having suffered a miscarriage (32%/p <0.0001) have high chances of acquiring this sexual infection. The ompA gene was sequenced in only 33 (42.8%) samples, revealing the genotype J was the most frequent (27.2% [9/33]), followed by genotypes D (24.2% [8/33]), and then genotypes F (18.2% [6/33]), E (15.1% [5/33]) K (6.1% [2/33]), Ia (6.1% [2/33]), and G (3.1% [1/33]). The high prevalence of sexual infection by C. trachomatis in the female university students from the interior of the state of Pará, individuals with no fixed sexual partner, those that had had a miscarriage, the students that do not use condoms in their sexual relations. The genotype J of C. trachomatis genotypes was the most frequent. These data are important to help defining the epidemiological effects of chlamydial infections in Amazonian populations.

First study on the metazoan parasite community of Crenicichla strigata (Cichliformes: Cichlidae).

This study provides the first report of metazoan parasites in Crenicichla strigata. From 31 hosts caught in the Jari River basin, in the eastern Amazon region of Brazil, a total of 1454 parasites were collected: Sciadicleithrum araguariensis, Sciadicleithrum joanae, Sciadicleithrum satanopercae, Posthodiplostomum sp., Genarchella genarchella, Contracaecum sp., Spirocamallanus peraccuratus, Acarina gen. sp. and Dolops geayi. However, the community was dominated by the three species of Sciadicleithrum (Monogenea) and there was similar presence of parasites in the larval and adult stages. The total prevalence was 100% and each of the hosts was parasitized by two or three species, which presented random dispersion. Brillouin diversity, parasite species richness, Berger-Parker dominance index and evenness were low. There was positive correlation between the abundance of Posthodiplostomum sp. the hosts' length, while the abundance of S. peraccuratus showed negative correlation with the body weight of fish. The abundance of S. araguariensis, S. joanae and S. satanopercae showed negative correlation with the hosts' length. The parasite community of C. strigata was characterized by low diversity, low richness, low intensity and low abundance of species.

Shifting cultivation in decline: An analysis of soil fertility and weed pressure in intensified cropping systems in Eastern Amazon

Reconciling forest preservation and agricultural production is a major challenge. In Brazil, environmental laws have been introduced to reduce forest degradation associated with the expansion of agriculture. However, these laws are constraining small-scale family farmers who rely on cassava produced in shifting cultivation. Faced by scarcity of land, farmers are reducing the fallow periods on their farms. In this study, our hypothesis was that the reduction of the fallow period in shifting cultivation systems leads to a depletion of soil fertility and an increase in weed pressure. In the Brazilian Eastern Amazon region, soil fertility and weed infestation indicators were assessed in 36 cassava fields under shifting cultivation with different land-use histories. The frequency of cultivation of the fields in the past 10 years ranged from 1 to 7 and averaged 3.7 ± 2.3. The results show that the most frequently cultivated fields had lower soil fertility, indicated by lower soil organic carbon, total nitrogen and exchangeable potassium and pH. In addition, labor input for weeding and weeding frequency increased with the frequency of cultivation of the fields, indicating that weed pressure increased with intensified crop cultivation and shorter fallow periods. The findings of this study make clear that the current trend of reducing the fallow period in the Eastern Amazon is a threat to the sustainability and productivity of the local shifting cultivation systems. There is an urgent need for alternative production systems that allow for a better weed control and that contribute to restoring and maintaining soil fertility.

Açaí palm intensification reorganizes woody plant assemblages at multiple spatial scales in an Amazonian estuarine forest

AbstractThe exploitation of nontimber forest products has been proposed as a sustainable way to exploit tropical forests, but such an opportunity remains to be examined case‐by‐case. We examine the impact of the intensification of the açaí palm (Euterpe oleracea) management for fruit production via increments in palm clumps/stems density on the woody plant assemblages (adult and regenerating) in an estuarine forest landscape in the eastern Amazon region, Brazil. Across 30 forest stands açaí stem density correlated negatively with stem density and taxonomic diversity considering both adult and regenerating woody plant assemblages, but it posed a positive effect on beta diversity via species turnover. Soil fertility and forest stand accessibility played a complementary role. Moreover, açaí clump density affected the abundance of particular woody plant species, including a set of species declining before the 400‐açaí clump density threshold imposed by current regulation. Accordingly, açaí clump density influenced the taxonomic organization of woody plant assemblages at the landscape spatial level. Finally, it is worth mentioning a group of 105 species, which were recorded across the regenerating assemblages but not in the adult assemblages. Among them, a large number of small‐statured woody plant species typical from the forest understory (i.e., the shade‐tolerant assemblage), such as those from Miconia, Piper, Bactris, Anonna and Geonoma genera. As intensification is still spreading it can be considered a threat to the integrity of the Amazon estuarine forest and thus questions the ecological sustainability through which the current Amazonian “black gold” is now produced.

GPR survey on underwater archaeological site: A case study at Jenipapo stilt village in the eastern Amazon region, Brazil

In this work we present and discuss the results of a pioneering Ground Penetrating Radar (GPR) survey performed at the underwater archaeological stilt village called Jenipapo in the eastern Amazon region. Jenipapo stilt village is located on the Turiaçu River, Maranhão State, Northeast of Brazil. The region is known as the Maranhense wetland where settlements were built by indigenous populations that inhabited this region during the pre-colonial period (∼AD 1 – 1100). These settlements were built on the margin of rivers and lakes, being supported by wooden pillars, corresponding to prehistoric stilt houses. The objectives of this research are to refine the wooden pillars location at the Turiaçu River bottom and guide the search for underwater archaeological artifacts. A total of twelve GPR profiles were acquired with 270 MHz antennas using a rubber boat. The GPR results indicated clear signal reflection from the river bottom and several diffraction hyperbolas suspended over the river bottom related to the top of the wooden pillars. To support the interpretation of the results, a GPR numerical modeling was performed to simulate the diffraction hyperbolas suspended in the water related to the wooden pillars. The synthetic result presented a good agreement with real data. Finally, the location of several diffraction hyperbolas can guide the divers to find and collect archaeological artifacts around the underwater wooden pillars that are the best evidence of the stilt houses of indigenous settlements found in the eastern Amazon region. Several archaeological artifacts were found during previous work, including ceramic materials. The results of this research show the capability of the GPR method to map an underwater wooden pillar and increase the probability of finding archaeological artifacts on the river bottom, which contributes to improve the knowledge of the Amazonian archaeology in Brazil.

Physico-Chemical Properties of Brazilian Eastern Amazon Honey Assessed by Multivariate Principal Components Analysis

Honey from the Apis mellifera bee (Hymenoptera, Apidae) is one of the most consumed beehive products in the world, mainly due to its nutritional and therapeutic value. In poorer regions, its commercialization can be an essential source of income for families and communities. However, the quality of honey can change both during harvesting and processing, as well as by climatic conditionsand the type of vegetation. Therefore, implementing good production practices, with quality control in collection and processing, can add value to this product, promoting the development of the region in which it is produced. Thus, the objectives of this work were to characterize the honey of Africanized honeybees produced in the Eastern Amazon region in the cities of Nova Olinda do Maranhão(NO), Santa Luzia do Paruá (SL) and verify its correlation with a commercial honey sample (CH) – from São Luiz-MA. The physicochemical properties (color, moisture, solids insoluble in water, minerals, and ash, hydroxymethylfurfural, acidity, anddiastatic activity) were analyzed according to the methods of CODEX Alimentarius and the Association of Official Analytical Chemists, and these data were evaluated by the Principal Component Analysis (PCA). The results showed that commercial honey presented higher levels of insoluble solids, HMF, minerals, and ash than samples from NO and SL. Variables that differentiated NO and SL honey were HMF, moisture, and diastase index. Although the samples have different characteristics, the data comply with Brazilian legislation, which can strengthen the development of apiculture in the region.

Aspects of Sexuality in Quilombola Communities’ Young Adults in Eastern Brazilian Amazon

Quilombola communities are descended from African slaves who escaped in resistance to imperial rule in Brazil. Today, these communities suffer from inadequate health care and health promotion programs due to socioeconomic, geographic, and political factors. This generates greater vulnerability among these groups because they have limited information about prevention to improve their quality of life. This research aimed to analyze the sexuality of young quilombola adults and the impact on their quality of life through an observational, cross-sectional, quantitative study with descriptive and inferential analyses. Our study is the first to address these issues among quilombolas in the Eastern Amazon region. The participants were 79 individuals of both sexes, aged between 18 to 35 years, belonging to seven communities in the state of Pará. The questionnaires were designed to assess sexual behavior and satisfaction, values and beliefs about sexuality, prejudice regarding sexual and gender diversity, knowledge about sexually transmitted infections (STIs), beliefs about maternity, and quality of life. Women reported greater sexual dissatisfaction and lower quality of life than men. Men reported no dysfunctions; however, they were highly prejudiced towards sexual and gender diversity. Low education negatively impacts the health of quilombola populations, as knowledge about STIs and values and beliefs influence sexual behavior, exposing individuals to diseases. The research also confirms that, both among quilombolas and other groups, factors such as sexual satisfaction, values and beliefs about reproduction, and affectivity directly influence the quality of life.

Adulteration of the Fuel Sold at Gas Stations in Two Towns in the Eastern Amazon Region of Northern Brazil

Purpose: The aimed witch of this study was to verify the quality of the fuel sold by gas stations in the Amazonian towns of Bragança and Tracuateua (Brazil). Method: It were applied physicochemical analyses to verify the anhydrous ethyl alcohol content of samples of gasoline, as well as the specific mass of samples of diesel and gasoline. Result and conclusion: Just over a quarter (26.47%) of the samples of gasoline collected in Bragança contained more ethanol than permitted by Brazilian law and were thus classified as in non-conformity. Three (75%) of the four gasoline samples from Tracuateua were non-conformity. In addition, 11.76% of the gasoline samples collected in Bragança were less dense at 20 °C than specified by the Brazilian legislation, and were thus considered as in non-conformity. Based on this same criterion, half (50%) of the gasoline samples collected in Tracuateua were also non-conformity. Diesel was the only fuel that presented no alteration in specific mass in either town. Research implications: There is a lack of academic studies related to this serious problem in the surveyed sites. This pioneering study is of great importance because it will alert local authorities about the problem of marketing fuels that do not meet the current specifications of the Brazilian legislation and whose emission of gases causes atmospheric pollution besides being harmful to life and to the environment. Originality/value: This study indicated that both types of gasoline (regular and premium) may be subject to adulteration in both Amazonian towns (Pará, Brazil).

Persistent olfactory dysfunction associated with poor sleep quality and anxiety in patients with long COVID.

Poor sleep quality have been widely reported in patients with long COVID. Determining the characteristics, type, severity, and relationship of long COVID with other neurological symptoms is essential for the prognosis and management of poor sleep quality. This cross-sectional study was conducted at a public university in the eastern Amazon region of Brazil between November 2020 and October 2022. The study involved 288 patients with long COVID with self-report neurological symptoms. One hundred thirty-one patients were evaluated by using standardised protocols: Pittsburgh sleep quality index (PSQI), Beck Anxiety Inventory, Chemosensory Clinical Research Center (CCRC), and Montreal Cognitive Assessment (MoCA). This study aimed to describe the sociodemographic and clinical characteristics of patients with long COVID with poor sleep quality and their relationship with other neurological symptoms (anxiety, cognitive impairment, and olfactory disorder). Patients with poor sleep quality were mainly women (76.3%), 44.04 ± 12.73 years old, with >12 years of education (93.1%), and had monthly incomes of up to US $240.00 (54.2%). Anxiety and olfactory disorder were more common in patients with poor sleep quality. Multivariate analysis shows that the prevalence of poor sleep quality was higher in patients with anxiety, and olfactory disorder is associated with poor sleep quality. In this cohort of patients with long COVID, the prevalence of poor sleep quality was highest in the group tested by PSQI and were associated with other neurological symptoms, such as anxiety and olfactory dysfunction. A previous study indicates a significant association between poor sleep quality and psychological disorders over time. Recent studies involving neuroimaging found functional and structural changes in Long COVID patients with persistent olfactory disfunction. Poor sleep quality are integral part of complex changes related to Long COVID and should be part of patient's clinical management.

Hepatozoon Miller, 1908 parasites in the Colubridae snakes Clelia clelia (Daudin, 1803) and Drymarchon corais (Boie, 1827) from the Eastern Amazonia

Based on the genetic, morphological, and morphometric data of blood gamonts, we identified Hepatozoon parasites in colubrid snakes sampled in the Eastern Amazon region. Hepatozoon trigeminum was detected in the mussurana snake Clelia clelia and exhibited wide and elongated gamonts (mean dimensions: 14.25±0.65 × 4.31±0.43 μm) with an evident parasitophorous vacuole. Hepatozoon odwyerae sp. nov. was described in the indigo snake Drymarchon corais, whose gamonts have elongated and thin bodies (mean dimensions: 13.41±0.79 × 3.72±0.35 μm) with one end more tapered than the other. Phylogenetic analyses, based on the amplification of a 441 bp fragment of the 18S rRNA gene, revealed that the novel sequences of Hepatozoon spp. from our study were closely related to hemogregarine lineages found in lizards and snakes from Brazil, forming a well-supported monophyletic clade with them. The present study provides the first species description of Hepatoozon in D. corais and a new record of a host species for C. clelia using the integrated taxonomic data. We also highlight the importance of further investigations into the diversity of Hepatozoon in snakes, a rich but underestimated group of parasites, especially in the Amazonian biome.