Navegando por Assunto "Porto Trombetas - PA"

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Caracterização morfológica e antigênica do vírus Juruaçá, isolado de morcego no estado do Pará
(Universidade Federal do Pará, 2006) ARAÚJO, Tais Pinheiro de; VASCONCELOS, Pedro Fernando da Costa; http://lattes.cnpq.br/0973550817356564
Juruaçá virus (BE AN 401933) was isolated from pooled organs of an unidentified bat captured during field work in Porto Trombetas, Oriximiná, Pará State, in 1982, and remains unclassified/ungrouped. The aims of this work were to classify Juruaçá virus in a viral taxon taking in account its morphological, physicochemical, antigenic and molecular properties, as well as, to describe the pathological alterations. This agent is pathogenic only for infant mice, and the animal’s death occurs with eight days post-inoculation. It’s not related to any of the arthropod borne viruses with which it has been tested by serological tests, such as complement fixation (CF) and hemagglutination inhibition (HI). Positive reactions were only observed with its homologous serum. Juruaçá virus is not sensitive to sodium desoxicolate and can hemagglutinate goose cells at pH 5.75. The virus didn’t show any cytophatic effect and immunofluorescence was negative in Vero and C6/36 cell lines, but it replicates in brain tissue primary culture cell line (astrocytes and microglias), confirmed by immunofluorescent assay (IFA). Culture of neuronal cells appears not to be infected by Juruaçá virus; however, infection of these cells was confirmed by imunohistochemistry. By transmission electron microscopy and negative stain, the virus is a spherical particle, with mean diameter of 23-30nm. Pathological alterations were observed mainly in the central nervous system of newborn mice experimentally infected with Juruaçá virus. The molecular results of RT-PCR suggest that Juruaçá virus is a possible new virus belonging to the family Picornaviridae, genus Enterovirus.
Acesso aberto (Open Access)
Colonização por anfíbios e lagartos de áreas reflorestadas no Platô Saracá, região de Porto Trombetas-Pará
(Universidade Federal do Pará, 2008) SARMENTO, João Fabrício de Melo; GALATTI, Ulisses; http://lattes.cnpq.br/1040132527458660
Few studies have considered faunal colonization of reforested areas after mining. To determine patterns of colonization of reforestation areas in Porto Trombetas, Pará, we examined species composition, richness, abundance and biological characteristics of amphibian and lizard species. Also I evaluated the effect of vegetation structure and distance to native forests on the community of amphibians in reforested areas. Amphibians and lizards were sampled along eight occasions in four-eight reforestation areas and four areas of native forests through active search and using artificial ponds for amphibian reproduction. Twenty species of amphibians and 20 species of lizards were registered, with 14 species of amphibians and 11 species of lizards in reforestations and 19 species of amphibians and 16 species of lizards in native forests. Among amphibians, Leptodactylus sp., Osteocephalus oophagus e Allobates femoralis were the most abundant species in the two environments. Among lizards, Gonatodes humeralis and Leposoma guianense were the most abundant species in reforestations and native forests, respectively. Amphibians with terrestrial reproduction or which use small temporary ponds to spawn and arboreal lizards were the most abundant groups in the reforested areas. Fossorial and semifossorial amphibians and litter lizards were the main absent groups in the reforested areas, suggesting that the current stage of vegetation succession does not offer appropriate microhabitats for some species. Species richness of amphibians was higher in areas with larger canopy cover. Areas with larger canopy cover had also higher abundance of Leptodactylus sp., A. femoralis and O. oophagus. Only four species of amphibians have used the artificial ponds for spawning and there was no significant relationship between the number of species that used the ponds and the distance to native forest or the canopy cover. Osteocephalus oophagus spawn in ponds most farer and A. femoralis in ponds closer to the native forest. Results show that amphibian and lizard fauna in reforestation areas is a subgroup of the native forest fauna and encompasses forest species which indicate the relative importance of these areas for the conservation of the local fauna.
Acesso aberto (Open Access)
Micromorfologia, mineralogia e geoquímica da bauxita nodular de Trombetas – PA
(Universidade Federal do Pará, 2018-10-18) LIMA, José Diogo de Oliveira; COSTA, Marcondes Lima da; http://lattes.cnpq.br/1639498384851302
Brazil's main bauxite deposits are concentrated in the Amazon region, specifically in the state of Pará. The three main mines are located in Trombetas, Paragominas and Juruti, and they’re responsible for 85% of Brazil's bauxite production. Even with the favorable mineral scenario in Brazil and especially in the state of Pará, there are already companies that are currently competitive in the current market, they are seeking to develop studies of the characterization and use of nodular bauxite in this type of deposit. The ore, so far, is considered as marginal, it means low-grade ore in the mineral industry. In this context, this work sought to evaluate Trombetas deposits’ nodular bauxite from their texture, mineralogical and chemical characteristics as a possible aluminum ore. In the field, seven lithographic profiles were described on the mining fronts of Bela Cruz and Monte Branco mines belonging to ‘Mineração Rio do Norte’. Then, 19 samples were collected, which were described, photographed and prepared for mineralogical and chemical analyzes. The mineralogical phases were identified by X-ray Diffraction (XRD) and Scanning Electron Microscopy coupled to the Dispersive Energy System (SEM/EDS). The textural aspects involved optical microscopy and Scanning Electron Microscopy coupled to the Dispersive Energy System (SEM/EDS). The chemical analyzes were performed by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), Inductively Coupled Plasma Mass Spectrometer (ICP-MS), X-ray Fluorescence (XRF), titulometry and gravimetry. The profiles investigated comprise from the base to the top the bauxite horizon (HBX) which is represented by gibbsite concretions surrounded by a clay matrix. The overlapped bauxite nodular horizon subdivided into HBNB, HBNI and HBNT, is formed by gibbsitic nodules, of fine texture, that impresses solid and porcelanate aspect and they are surrounded by a clayey matrix. The clay cover (CAR) at the top is formed by a yellow clay, corresponding to Belterra Clay. In the profiles, the fragments > 0.500 and ~0.500 mm of the HBX and HBNB, HBNI and HBNT are essentially composed of gibbsite associated with kaolinite, hematite and anatase. The dominance of gibbsite in the fragments > 0.500 and ~ 0.500 mm of the HBNB, HBNI and HBNT, presents a potential of nodular bauxite as a possible aluminum ore. However the fragments < 0.500 mm, clayey matrix of HBX and HBNB, HBNI, HBNT and CAR are mainly composed of kaolinite associated with gibbsite, hematite, quartz and anatase. The kaolinite domain in the HBNB, HBNI, HBNT fragments < 0.500 mm, makes it difficult to consider them as possible aluminum ore. As for the heavy minerals (zircon, rutile and tourmaline), no contrast was found between the horizons and the clayey cover. The chemical composition consists essentially of SiO2, Al2O3, Fe2O3 and TiO2, which reinforce the main minerals identified and as these the contents differ according to the horizons. The concentrations of the trace elements are variable, V, Cr, Ga, Se, Zr, Nb, Mo, Sn, Hf, Ta, W, Hg, Bi, Th and U are above the crustal average in all fragments, clayey matrix of HBX, HBNB, HBNT and CAR. Trace elements such as V, Cr, Ga, Mo, Hg and Bi correlate positively with Fe2O3 (hematite and goethite). While Nb, Sn, Hf, Ta, Th, U, correlate positively with zirconium (zircon) and titanium (anatase). When normalized to the chondrites, the distribution curves present parallelism between the various fragments, clayey matrix of HBX, HBNB, HBNT and CAR, with curves that exhibit Eu anomaly, as well as an enrichment of the heavy rare earth elements (HREE) in front of the light rare earths elements (LREE). The data obtained in the investigated profiles of Bela Cruz and Monte Branco mines demonstrate broad similarity to Belterra clay-type nodular lateritic-bauxite profiles found in Amazon, where the clayey matrix of the nodules resembles textural, chemical (larger elements and traces) and mineralogical (including heavy minerals) with this covering clay.