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In this paper we post-process and evaluate the position estimation of pairs of template windows and geo-referenced images generated from LiDAR cloud point data using the Normalized Cross-Correlation (NCC) method. We created intensity, surface and terrain pairs of images for use with template matching, with 5 m pixel spacing, through binning. We evaluated square and circular binning approaches, without filtering the original data. Template matching achieved approximately 7 m root mean square error (RMSE) on intensity and surface templates on the respective geo-referenced images, while on terrain templates it had many mismatches due to insufficient terrain features over the assumed flight transect. Analysis of NCC showed the possibility of rejecting bad matches of intensity and surface templates, but terrain templates required an additional criteria of flatness for rejection. The combined NCC of intensity, surface and terrain proved stable for rejection of bad matches and had the lowest RMSE. Filtering outliers from surface images changed very little the accuracy of the matches, but greatly improved correlation values, indicating that the forest canopy might have the best features for geo-localization with template matching. Position estimation is essential for autonomous navigation of aerial vehicles and the these experiments with LiDAR data show potential for localization over densely forested regions where methods using optical camera data may fail to acquire distinguishable features. [ABSTRACT FROM AUTHOR]

The paper explores the evolution of the bilateral relations between Brazil and Suriname during the 1980s, especially with the so-called Venturini mission to Suriname. The text uses original documents from two Brazilian archives. The article shows that the main goals of Figueiredo's administration with respect to Suriname were fulfilled, especially concerning the avoidance of an East-West conflict in the sensitive north frontier of the country and in the Amazon region. [ABSTRACT FROM AUTHOR]

Construction and Demolition Waste (CDW) cause environmental impacts in a worldwide scale. The existing international concern regarding the adequate management of CDW is justified by the large amount of this waste produced in a daily basis, together with its potential hazardous effects on ecosystems and human health. In this scope, the application of Circular Economy principles to the construction industry is of the utmost importance to define management strategies regarding CDW. Although highly dependent on policies developed at the national level, the promotion of circularity in construction materials usage is also at the reach of local administration bodies. The present research identifies strategies for CDW management at the regional level, involving different stakeholders of the construction industry. These strategies were successfully operationalized through a case study focusing CDW management in the municipality of Manaus, in the centre of the Amazon Forest. The characterization of the reference situation regarding CDW management in Manaus revealed several deficiencies, namely the lack of reuse and recycling opportunities, the unsupervised disposal of CDW in illegal landfills, together with insufficient surveillance procedures and inadequate policies from regional authorities. Improved CDW management strategies were identified and operationalized: valorization of CDW through the enhancement of reuse and recycling opportunities, operationalized through a mobile phone application; reinforcement of training and surveillance practices; and alterations in the municipal policies regarding CDW disposal in the public landfill. The CDW management strategies described and validated in this research are applicable to other Brazilian municipalities or to other countries' realities, promoting sustainability-oriented practices that can co-exist with economic development. [ABSTRACT FROM AUTHOR]

Features of negative cloud‐to‐ground (CG) flashes in the eastern Amazon region of Brazil, near the equator line, were analyzed from their wideband (160 Hz–10 MHz) electric field records acquired at the UFPA‐Lightning Research Laboratory in Belem, Para, Brazil in the rainy season of 2020. Records of CG flashes were synchronized in time with the Geostationary Lightning Mapper (GLM) data. We found that the GLM relative detection efficiency for negative CG flashes in the region of study is 78.5%. For a subset of 613 flashes that were detected by the GLM, we segregate the events into three categories (close‐, intermediate‐ and distant‐range) according to the GLM reported locations. Flash multiplicity, interstroke time interval, flash duration, leader duration, preliminary‐breakdown (PB) pulse train duration, PB to first return‐stroke (RS) time interval, and the ratio of PB to first RS are determined for 781 negative CG flashes containing 2,383 strokes. The results were compared with previous results obtained in different parts of the globe with an emphasis on studies performed in similar regions such as in the tropics. For all flashes, the average number of strokes per flash is 3.1 and the percentage of single‐stroke flash is 30%. The geometric mean of interstroke intervals, flash duration, PB to first RS time interval, and PB pulse train duration are 63, 186, 10, and 1.5 ms, respectively. Key Points: For the first time, a detailed stroke count study is performed in the Brazilian Amazon region, using wideband electric field dataCharacteristics of cloud‐to‐ground (‐CG) lightning flashes including preliminary breakdown, leaders, and return‐strokes are analyzedThe results show no significant differences between ‐CG flashes that occur in the Amazon region and other regions of the globe [ABSTRACT FROM AUTHOR]

Ongoing studies of Neotropical Euphorbiaceae have uncovered a surprising number of new species belonging to Croton L. sect. Cleodora (Klotzsch) Baill., one of the better studied clades in the genus. Here we describe six new species and reclassify three others that were either misplaced to section or regarded as species of unknown phylogenetic affinity in previous studies. The new species are all from South America, and five of them are restricted to the Amazon region. We update the most recent taxonomic revision of Croton sect. Cleodora by providing a new taxon list and an identification key for the 27 currently recognized species. Sixteen species occur in lowland forested areas of the Amazon basin. Our finding calls attention to the Neotropics, and the Amazon region in particular, where information about the flora and species geographic ranges is still incomplete, even for relatively well-studied plant groups. [ABSTRACT FROM AUTHOR]

This is an observational study of the large-scale moisture transport over South America, with some analyses on its relation to subtropical rainfall. The concept of aerial rivers is proposed as a framework: it is an analogy between the main pathways of moisture flow in the atmosphere and surface rivers. Opposite to surface rivers, aerial rivers gain (lose) water through evaporation (precipitation). The magnitude of the vertically integrated moisture transport is discharge, and precipitable water is like the mass of the liquid column-multiplied by an equivalent speed it gives discharge. Trade wind flow into Amazonia, and the north/northwesterly flow to the subtropics, east of the Andes, are aerial rivers. Aerial lakes are the sections of a moisture pathway where the flow slows down and broadens, because of diffluence, and becomes deeper, with higher precipitable water. This is the case over Amazonia, downstream of the trade wind confluence. In the dry season, moisture from the aerial lake is transported northeastward, but weaker flow over southern Amazonia heads southward toward the subtropics. Southern Amazonia appears as a source of moisture to this flow. Aerial river discharge to the subtropics is comparable to that of the Amazon River. The variations of the amount of moisture coming from Amazonia have an important effect over the variability of discharge. Correlations between the flow from Amazonia and subtropical rainfall are not strong. However, some months within the set of dry seasons observed showed a strong increase (decrease) occurring together with an important increase (decrease) in subtropical rainfall. [ABSTRACT FROM AUTHOR]

This article examines the relationship between increased metal mining and sustainable development in the eastern section of the Amazonian state of Pará in Brazil. Since the early 1980s, mining has grown rapidly in Pará and local mining operations have become global leaders in the production of iron, manganese, bauxite, aluminum, gold, copper and — in the near future — nickel. To stay in tune with global standards, these companies have committed themselves to the principles of sustainability and have obtained certification for both social and environmental aspects of their activities. The article looks into whether such certification is linked to sustainable development of the relatively poor regions where these companies operate. The main findings are that: (1) there is a visible association between certification and improved performance by the companies, but not with the development of nearby areas; and (2) social-environmental certification processes place more emphasis on ecological variables than on social ones. [ABSTRACT FROM AUTHOR]

Mercury in the aquatic biota and geologic materials in areas without anthropogenic sources has been stimulating the discussion about the possibility of natural Hg occurrence in the Amazon region. In this study the dispersion of Hg in different geologic materials as well as its relationship with high Hg levels, detected in some species of carnivorous fish consumed in the Rio Branco city, is evaluated. Bottom and suspended sediments, river water and fishes were sampled in the Acre and Purus Rivers and in some of their tributaries. Total mercury as well as physical and chemical characterization of the waters were done. Hg on top soil and upper horizons samples were also determined to evaluate the potential Hg accumulation in these materials. In addition the dominant minerals were determined by X-ray Diffraction analysis. Furthermore, ten samples of fossilized material were analyzed. The Hg analysis were carried out by CVAAS. The Hg mean levels in the bottom and suspensed sediments were 0.042 and 0.060 μg g-1, respectively. In the river water samples, the Hg levels were below the detection limit. The Hg mean values in the different soil samples were as follow: soil samples (0.077 μ g-1), lower (50–60 cm depth) horizons samples (0.117 μ g-1), ferruginous nodules within the clayey matrix (0.190 μ g-1) and fossilized material (0.379 μ g-1). In the fishes the Hg levels are high with mean of the 1.287 μ g-1 in the carnivorous species. These levels indicate a possible bioaccumulation of Hg mostly in the carnivorous fishes. Although low concentrations of Hg were found in the river waters, it is assumed here that the bioavailable Hg can is original large from the ferruginous nodules and fossilized materials. [ABSTRACT FROM AUTHOR]

The lack of usable aggregates for civil construction in Rio Branco (capital of Acre, a Federal State in the Amazon region) makes the production and use of recycled aggregates from construction and demolition waste (CDW) an alternative of great interest. In this study, a comprehensive characterization of CDW collected from 24 construction sites of six building types and three different construction phases (structures, masonry, and finishing) was carried out. The fine and coarse recycled aggregates were produced and evaluated in 10 different compositions. The aggregates' performance was evaluated in four mixtures designed for laying and coating mortars with a total replacement of conventional aggregates and a mixture designed for a C25 concrete with 50% and 100% replacement of conventional aggregates. CDW mortars showed lower densities and greater water retention, initial adhesion, and mechanical strength than conventional mortars. CDW concretes presented lower densities and greater resistance to chloride penetration than conventional concrete, with a small mechanical strength reduction. The recycled CDW aggregates proved to be technologically feasible for safe application in mortars and concrete; for this reason, it is believed that the alternative and proposed methodology is of great interest to the Amazonian construction industry, considering the high costs of raw materials and the need for defining and consolidating a sustainable development model for the Amazon region. [ABSTRACT FROM AUTHOR]