997 resultados para Brazilian Amazon rainforest


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The Amazon basin is a region of constant scientific interest due to its environmental importance and its biodiversity and climate on a global scale. The seasonal variations in water volume are one of the examples of topics studied nowadays. In general, the variations in river levels depend primarily on the climate and physics characteristics of the corresponding basins. The main factor which influences the water level in the Amazon Basin is the intensive rainfall over this region as a consequence of the humidity of the tropical climate. Unfortunately, the Amazon basin is an area with lack of water level information due to difficulties in access for local operations. The purpose of this study is to compare and evaluate the Equivalent Water Height (Ewh) from GRACE (Gravity Recovery And Climate Experiment) mission, to study the connection between water loading and vertical variations of the crust due to the hydrologic. In order to achieve this goal, the Ewh is compared with in-situ information from limnimeter. For the analysis it was computed the correlation coefficients, phase and amplitude of GRACE Ewh solutions and in-situ data, as well as the timing of periods of drought in different parts of the basin. The results indicated that vertical variations of the lithosphere due to water mass loading could reach 7 to 5 cm per year, in the sedimentary and flooded areas of the region, where water level variations can reach 10 to 8 m.

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We measured the mixing ratios of NO, NO2, O-3, and volatile organic carbon as well as the aerosol light-scattering coefficient on a boat platform cruising on rivers downwind of the city of Manaus (Amazonas State, Brazil) in July 2001 (Large-Scale Biosphere-Atmosphere Experiment in Amazonia-Cooperative LBA Airborne Regional Experiment-2001). The dispersion and impact of the Manaus plume was investigated by a combined analysis of ground-based (boat platform) and airborne trace gas and aerosol measurements as well as by meteorological measurements complemented by dispersion calculations (Hybrid Single-Particle Lagrangian Integrated Trajectory model). For the cases with the least anthropogenic influence (including a location in a so far unexplored region similar to 150 km west of Manaus on the Rio Manacapuru), the aerosol scattering coefficient, sigma(s), was below 11 Mm(-1), NOx mixing ratios remained below 0.6 ppb, daytime O-3 mixing ratios were mostly below 20 ppb and maximal isoprene mixing ratios were about 3 ppb in the afternoon. The photostationary state (PSS) was not established for these cases, as indicated by values of the Leighton ratio, Phi, well above unity. Due to the influence of river breeze systems and other thermally driven mesoscale circulations, a change of the synoptic wind direction from east-northeast to south-southeast in the afternoon often caused a substantial increase of ss and trace gas mixing ratios (about threefold for sigma(s), fivefold for NOx, and twofold for O-3), which was associated with the arrival of the Manaus pollution plume at the boat location. The ratio F reached unity within its uncertainty range at NOx mixing ratios of about 3 ppb, indicating "steady-state" conditions in cases when radiation variations, dry deposition, emissions, and reactions mostly involving peroxy radicals (XO2) played a minor role. The median midday/afternoon XO2 mixing ratios estimated using the PSS method range from 90 to 120 parts per trillion (ppt) for the remote cases (sigma(s) < 11 Mm(-1) and NOx < 0.6 ppb), while for the polluted cases our estimates are 15 to 60 ppt. These values are within the range of XO2 estimated by an atmospheric chemistry box model (Chemistry As A Box model Application-Module Efficiently Calculating the Chemistry of the Atmosphere (CAABA/MECCA)-3.0).

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Rainfall, throughfall and stemflow were monitored on an event basis in an undisturbed open tropical rainforest with a large number of palm trees located in the southwestern Amazon basin of Brazil. Stemflow samples were collected from 24 trees with a diameter at breast height (DBH) > 5 cm, as well as eight young and four full-grown babassu palms (Attalea speciosa Mart.) for 5 weeks during the peak of the wet season. We calculated rainfall, throughfall and stemflow concentrations and fluxes of Na+, K+, Ca2+, Mg2+,, Cl-, SO42-, NO3- and H+ and stemflow volume-weighted mean concentrations and fluxes for three size classes of broadleaf trees and three size classes of palms. The concentrations of most solutes were higher in stemflow than in rainfall and increased with increasing tree and palm size. Concentration enrichments from rainfall to stemflow and throughfall were particularly high (81-fold) for NO3-. Stemflow fluxes of NO3- and H+ exceeded throughfall fluxes but stemflow fluxes of other solutes were less than throughfall fluxes. Stemflow solute fluxes to the forest soil were dominated by fluxes on babassu palms, which represented only 4% of total stem number and 10% of total basal area. For NO3-, stemflow contributed 51% of the total mass of nitrogen delivered to the forest floor (stemflow + throughfall) and represented more than a 2000-fold increase in NO3- flux compared what would have been delivered by rainfall alone on the equivalent area. Because these highly localized fluxes of both water and NO3- persist in time and space, they have the potential to affect patterns of soil moisture, microbial populations and other features of soil biogeochemistry conducive to the creation of hotspots for nitrogen leaching and denitrification, which could amount to an important fraction of total ecosystem fluxes. Because these hotspots occur over very small areas, they have likely gone undetected in previous studies and need to be considered as an important feature of the biogeochemistry of palm-rich tropical forest. (C) 2011 Elsevier B.V. All rights reserved.

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The dynamics, over the last 7500 years, of a mangrove at Marajo Island in northern Brazil were studied by pollen and sedimentary facies analyses using sediment cores. This island, located at the mouth of the Amazon River. is influenced by riverine inflow combined with tidal fluctuations of the equatorial Atlantic Ocean. Herbaceous vegetation intermingled with rainforest dominates the central area of the island, while varzea is the main vegetation type along the littoral. In particular, the modem northeastern coastal zone is covered by a mosaic of dense rainforest, herbaceous vegetation, mangroves, varzea, and restinga. The integration of pollen data and fades descriptions indicates a tidal mud flat colonized by mangroves in the interior of Marajo Island between similar to 7500 cal yr BP and similar to 3200 cal yr BP. During the late Holocene, mangroves retracted to a small area (100-700 m in width) along the northeastern coastal plain. Mangrove expansion during the early and mid Holocene was likely caused by the post-glacial sea-level rise which, combined with tectonic subsidence, led to a rise in tidal water salinity. Salinity must have further increased due to low river discharge resulting from increased aridity during the early and mid Holocene. The shrinking of the area covered by mangrove vegetation during the late Holocene was likely caused by the increase in river discharge during the late Holocene, which has maintained relatively low tidal water salinity in Marajo Island. Tidal water salinity is relatively higher in the northeastern part of the island than in others, due to the southeast-northwest trending current along the littoral. The mixing of marine and riverine freshwater inflows has provided a refuge for mangroves in this area. The increase in flow energy during the last century is related to landward sand migration, which explains the current retraction of mangroves. These changes may indicate an increased exposure to tidal influence driven by the relative sea-level rise, either associated with global fluctuations or tectonic subsidence, and/or by an increase in river water discharge. (C) 2012 Elsevier B.V. All rights reserved.

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Brazil is one of the world's largest countries with a rich diversity of wildlife, including resident and migratory wild birds, which may be natural reservoirs of the Newcastle disease virus (NDV). Because Brazil is a major global exporter of chicken meat, the emergence of such a disease may have a huge negative impact not only on the economy due to trade restrictions and embargoes, but also on the quality of life of the population. Samples were collected from 1,022 asymptomatic domestic and wild birds from the Brazilian coast and the Amazon region using tracheal/cloacal swabs and tested by RT-qPCR. The results showed 7 (0.7%) birds were positive for NDV. The positive samples were then isolated in embryonated chicken eggs and their matrix protein genes were partially sequenced, revealing a low-pathogenicity NDV. This study confirms the maintenance of the velogenic-NDV free status of Brazil.

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Lebiasina marilynae n. sp., L. melanoguttata n. sp., and L. minuta n. sp. are described from the headwaters of the rio Curuá, in Serra do Cachimbo, Pará, Brazil, and represent the only members of the Lebiasininae in the Brazilian Shied, so far. A close relationship among these species is proposed based on: 1) the presence of a pair of foramina through which the ramus palatinus of the facial nerve passes, a modification unique in Lebiasinidae and apparently in the Characiformes, 2) the enlargement of the extrascapular bone, 3) the absence of the secondary stripe, and 4) the nearly equal length of caudal-fin lobes. Lebiasina marilynae additionally differs from all congeners in having the primary stripe extending from the tip of the snout to the distal border of the caudal-fin peduncle, the possession of two series of dark blotches parallel to the primary stripe, and a rounded dorsal surface of the mesethmoid. Lebiasina melanoguttata and Lebiasina minuta additionally differ from all congeners in the absence of the primary stripe and the caudal blotch, and the presence of three longitudinal series of dark blotches at the base of the scales of series 3-5. Lebiasina melanoguttata differs from Lebiasina minuta in the absence of a dark blotch at the base of the median rays of the dorsal fin, second infrapharyngobranchial bearing conical teeth, the reddish overall coloration of the eye and fins, and the dark blotches never coalescing (vs. dark dorsal-fin blotch present; the second infrapharyngobranchial being edentulous; dark, olive green eyes, and the yellowish overall color of body and fins; and the dark blotches of longitudinal series 3 and 4 coalescing where scales of adjacent longitudinal series overlap). The occurrence of species of the Lebiasininae on the Brazilian Shield is discussed, and the distribution pattern of the species described herein is compared to that of other endemic species of the Serra do Cachimbo, a highly biodiverse area isolated from the rest of the Amazon basin.

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A 67-year-old plantation of Flindersia brayleyana F. Muell. in the wet tropics of north-cast Queensland had developed with minimal management. Before thinning, the stand had a canopy stem density of 770 stems ha(-1) of which 564 were F brayleyana, a stand basal area of 78 m(2) ha(-1), a mean stem diameter at breast height (dbh) of 36 cm, and a mean dbh increment of 5.2 mm year(-1) over the life of the plantation and 0.5 mm year I at the time of thinning. Sixty-three percent of the trees had crown ratios (crown diameter determined from foliage projected area: dbh) of less than 12. Thinning treatments removed 57% of the canopy stems and 45% of the stand basal area. Mean dbh increment over 2.5 years after thinning on basaltic soil was 5.8 +/- 0.3 mm year(-1), but for trees with crown ratio

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The Andean and the amazon, comprised of Venezuela, Colombia, Bolivia, Peru and Ecuador, have recently undertaken significant modernization efforts ranging from equipment, logistics, doctrine, training, deployment and the re-definition of the roles and missions of their forces. In most cases, motivations to modernize have been internal, such as continuing operations against armed groups as in the case of Colombia and Peru, enhance border control and sovereignty enforcement, as in the case of Ecuador and Brazil or regime control in Venezuela. However, they are complemented by perceptions of external threats, including traditional intra-state conventional wars. The increased tensions between Colombia and Venezuela and Ecuador as well as the historic Peru-Chile tensions are the most salient examples. Although diplomacy –especially defence diplomacy- has worked to a good degree in creating and strengthening confidence building measures, the potential for inter-state conflict is higher in this region of the Americas. This region has seen the recent emergence of long-term modernization plans, initially in Colombia followed by Venezuela and Ecuador and probably best embodied in scope and scale by the Brazilian National Defence Plan (for its long term vision). Although it has been speculated that high allocation of funds to retirement pension systems has had an impact on delaying modernization plans, this comparative study on the allocation of pension and social funds in these particular countries concludes that there is no direct linkage between the poor funding of military modernization plans and the diversion of funds to military pension systems.

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In this work humic substances (HS) extracted from non-flooded (Araca) and flooded (Iara) soils were characterized through the calculation of stability and activation energies associated with the dehydration and thermal decomposition of HS using TGA and DTA, electronic paramagnetic resonance and C/H, C/N and C/O atomic ratios. For HS extracted from flooded soils, there was evidence for the influence of humidity on the organic matter humification process. Observations of thermal behaviour, with elemental analysis, indicated the presence of fossilized organic carbon within clay particles, which only decomposed above 800 C. This characteristic could explain the different thermal stability and pyrolysis activation energies for Iara HS compared to Araca HS.

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The aim of this study was to investigate the component community of parasite metazoans of Piaractus brachypomus in the lower Amazon River, northern Brazil. From 34 necropsied fish, 27,384 metazoan parasites were collected, such as Anacanthorus spathulatus, Mymarothecium viatorum and Notozothecium janauachensis (Monogenoidea); Spectatus spectatus and Contracaecum sp (Nematoda); Clinostomum marginatum and Dadaytrema oxycephala (Digenea); and Argulus carteri and Ergasilus sp. (Crustacea). The dominant species was S. spectatus followed by monogenoidean species, and there was aggregated dispersion of parasites, except for D. oxycephala and Contracaecum sp., which presented random dispersion. Positive correlation among the abundance of the three monogenoideans species were found, thus indicating that there was no competition between the species of these parasites on the gills of hosts. The abundances of some parasite species showed positive correlations with the size of the hosts, but the condition factor of the fish was not affected by the parasitism levels. It showed that this host had a metazoan community characterized by high species richness of metazoans, low evenness and high diversity of parasites, with prevalence of endoparasites, including larval stages. This was the first record of C. marginatum, A. carteri, Ergasilus sp. and Contracaecum sp. for P. brachypomus.

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Neste trabalho faz-se a divulgação do potencial de carvões e resíduos orgânicos parcialmente carbonizados visando obter materiais que mimetizam a matéria orgânica do solo das Terras Pretas de Índio da Amazônia, e que sirvam como condicionadores de solo e seqüestrem carbono de forma recalcitrante e reativa. Pesquisas desenvolvidas por grupos brasileiros e estrangeiros têm contribuído para o entendimento do surgimento e utilização das Terras Pretas de Índio da Amazônia. Aqui são divulgados resultados de estudos químicos no sentido do desenvolvimento do conhecimento científico e tecnológico e de inovação no aproveitamento de subprodutos orgânicos, principalmente de indústrias de biocombustíveis, carvão vegetal metalúrgico e outros, buscando imitar a excelente performance da chamada Terras Pretas de Índio da Amazônia.

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The aim of the study was to analyze the frequency of epidermal growth factor receptor (EGFR) mutations in Brazilian non-small cell lung cancer patients and to correlate these mutations with response to benefit of platinum-based chemotherapy in non-small cell lung cancer (NSCLC). Our cohort consisted of prospective patients with NSCLCs who received chemotherapy (platinum derivates plus paclitaxel) at the [UNICAMP], Brazil. EGFR exons 18-21 were analyzed in tumor-derived DNA. Fifty patients were included in the study (25 with adenocarcinoma). EGFR mutations were identified in 6/50 (12 %) NSCLCs and in 6/25 (24 %) adenocarcinomas; representing the frequency of EGFR mutations in a mostly self-reported White (82.0 %) southeastern Brazilian population of NSCLCs. Patients with NSCLCs harboring EGFR exon 19 deletions or the exon 21 L858R mutation were found to have a higher chance of response to platinum-paclitaxel (OR 9.67 [95 % CI 1.03-90.41], p = 0.047). We report the frequency of EGFR activating mutations in a typical southeastern Brazilian population with NSCLC, which are similar to that of other countries with Western European ethnicity. EGFR mutations seem to be predictive of a response to platinum-paclitaxel, and additional studies are needed to confirm or refute this relationship.

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To assess the prevalence of Climacteric Syndrome (CS) in women from a municipality of Northeastern Brazil which is less developed socioeconomically. A prospective household survey was performed in São Luís, Maranhão, Brazil with 1,210 climacteric women aged 45 to 60 years. Interviews were applied using previously tested standard questionnaires from April to July 2008. The severity of climacteric symptoms was analyzed by circulatory and psychological indexes and the latter were associated with menopausal status. Multiple correspondence analysis was used to assess the relation among climacteric symptoms. Most patients were 55 to 60 years old (35.3%), mulatto (37.9%), with 9-11 years of schooling (39.8%), with a partner (56%), Catholic (73.9%) and belonged to the socioeconomic class C (51.1%). The prevalence of CS was 85.9%, and hot flashes (56.4%) and sweating (50.4%) were the most prevalent symptoms. The most frequent psychological symptoms were nervousness (45%) and emotional liability (44.8%). The severity of vasomotor and psychological symptoms was significantly higher during the peri and postmenopausal period (p<0.05). Vaginal dryness (62.7%) was the most prevalent urogenital complaint. The prevalence of CS was high among women from São Luís, Maranhão, Brazil.

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Few studies have evaluated the profile of use of disease modifying drugs (DMD) in Brazilian patients with spondyloarthritis (SpA). A common research protocol was applied prospectively in 1505 patients classified as SpA by criteria of the European Spondyloarthropathies Study Group (ESSG), followed at 29 referral centers in Rheumatology in Brazil. Demographic and clinical variables were obtained and evaluated, by analyzing their correlation with the use of DMDs methotrexate (MTX) and sulfasalazine (SSZ). At least one DMD was used by 73.6% of patients: MTX by 29.2% and SSZ by 21.7%, while 22.7% used both drugs. The use of MTX was significantly associated with peripheral involvement, and SSZ was associated with axial involvement, and the two drugs were more administered, separately or in combination, in the mixed involvement (p < 0.001). The use of a DMD was significantly associated with Caucasian ethnicity (MTX , p = 0.014), inflammatory back pain (SSZ, p = 0.002) , buttock pain (SSZ, p = 0.030), neck pain (MTX, p = 0.042), arthritis of the lower limbs (MTX, p < 0.001), arthritis of the upper limbs (MTX, p < 0.001), enthesitis (p = 0.007), dactylitis (MTX, p < 0.001), inflammatory bowel disease (SSZ, p < 0.001) and nail involvement (MTX, p < 0.001). The use of at least one DMD was reported by more than 70% of patients in a large cohort of Brazilian patients with SpA, with MTX use more associated with peripheral involvement and the use of SSZ more associated with axial involvement.

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Long-acting reversible contraceptives (LARCs) include the copper-releasing intrauterine device (IUD), the levonorgestrel-releasing intrauterine system (LNG-IUS) and implants. Despite the high contraceptive efficacy of LARCs, their prevalence of use remains low in many countries. The objective of this study was to assess the main reasons for switching from contraceptive methods requiring daily or monthly compliance to LARC methods within a Brazilian cohort. Women of 18-50 years of age using different contraceptives and wishing to switch to a LARC method answered a questionnaire regarding their motivations for switching from their current contraceptive. Continuation rates were evaluated 1 year after method initiation. Sample size was calculated at 1040 women. Clinical performance was evaluated by life table analysis. The cutoff date for analysis was May 23, 2013. Overall, 1167 women were interviewed; however, after 1 year of use, the medical records of only 1154 women were available for review. The main personal reason for switching, as reported by the women, was fear of becoming pregnant while the main medical reasons were nausea and vomiting and unscheduled bleeding. No pregnancies occurred during LARC use, and the main reasons for discontinuation were expulsion (in the case of the IUD and LNG-IUS) and a decision to undergo surgical sterilization (in the case of the etonogestrel-releasing implant). Continuation rate was ~95.0/100 women/year for the three methods. Most women chose a LARC method for its safety and for practical reasons, and after 1 year of use, most women continued with the method.