Federal Rural University of Amazonia

Paragominas, Brazil
Time filter
Source Type

Da Silva-Neto I.D.,Federal University of Rio de Janeiro | Da Silva Paiva T.,Federal University of Rio de Janeiro | Do Nascimento Borges B.,Federal Rural University of Amazonia | Harada M.L.,Federal University of Pará
Journal of Eukaryotic Microbiology | Year: 2016

Metopid armophoreans are ciliates commonly found in anaerobic environments worldwide; however, very little is known of their fine structure. In this study, the metopid Parametopidium circumlabens (Biggar and Wenrich 1932) Aescht, 1980, a common endocommensal of sea urchins, is investigated for the first time with emphasis on transmission electron microscopy, revealing several previously unknown elements of its morphology. Somatic dikinetids of P. circumlabens have a typical ribbon of transverse microtubules, an isolated microtubule near triplets 4 and 5 of the anterior kinetosome, plus two other microtubules between anterior and posterior kinetosomes, a short kinetodesmal striated fiber and long postciliary microtubules. In the dikinetids of the perizonal stripe, the kinetodesmal fiber is very pronounced, and there is a conspicuous microfibrillar network system associated with the kinetosomes. A new structure, shaped as a dense, roughly cylindrical mass surrounded by microtubules, is found associated with the posterior kinetosome of perizonal dikinetids. The paroral membrane is diplostichomonad and the adoral membranelles are of the "paramembranelle" type. Bayesian inference and maximum-likelihood analysis of the 18S-rDNA gene unambiguously placed P. circumlabens as sister group of the cluster formed by ((Atopospira galeata, Atopospira violacea) Metopus laminarius) + Clevelandellida, corroborating its classification within the Metopida. © 2015 The Author(s) Journal of Eukaryotic Microbiology.

Moscoso V.,Federal Rural University of Amazonia | Albernaz A.L.,Federal Rural University of Amazonia | Salomao R.D.P.,Coordination of Botany
Forest Ecology and Management | Year: 2013

Knowledge of the distribution of plant species is essential for planning management and conservation actions, especially for economically important species. Available data on plant species in the Amazon usually do not represent their whole area of occurrence. The most widely used approach to infer predictions on species occurrence is niche modelling, which consists of correlating records of species with environmental conditions in their occurrence areas, generating maps with the potential distribution based on a combination of environmental features suitable for each species. The main objective of this study was to evaluate the ability of modelling to improve knowledge on the distribution of six timber species and six palm trees in the Amazon, and whether these models can benefit from using data from field surveys added to those of biological collections. Models were generated using the Maxent algorithm. All models generated showed a low extrinsic omission rate (TOE) and AUC above 0.75. Areas predicted for timber species were more consistent with empirical knowledge than those predicted for palm trees, probably due to the greater amount of occurrence sites available for timber species, especially after adding data from field surveys. The extent of the predicted area and the Jaccard index were used to compare the maps after insertion of field survey data. There was a large difference in extent just for two species, one timber and one palm, and a reduction in the predicted area for one species, Swietenia macrophylla. The application of the Jaccard index resulted in values between 0.41 and 0.65 for timber species, reinforcing that the inclusion of field survey data changed predicted areas. For palms, the similar extent of predicted areas and Jaccard values above 0.80, indicated a subtle difference between maps generated before and after the inclusion of field survey records, probably due to the addition of fewer records. The exception was Astrocaryum murumuru, for which the new records increased the extent of the predicted area. The niche models associated with field studies can contribute enormously to increase knowledge concerning the current distribution of species, but new field surveys should be carefully designed to cover wide and undersampled areas. However, it is necessary to consider that this strategy can only be adopted for species with clearly distinctive features, for which field identifications are reliable. © 2013 Elsevier B.V.

Garcia A.M.,Grande Rio University | Vieira J.P.,Grande Rio University | Winemiller K.O.,Texas A&M University | Moraes L.E.,Grande Rio University | Paes E.T.,Federal Rural University of Amazonia
Marine Ecology Progress Series | Year: 2012

We employed a new approach linking multivariate and time series analyses to identify common versus unique spatiotemporal components of abundance variation of marine spawning fishes recruiting into a subtropical Western Atlantic estuary. Based on a 10 yr standardized monthly data set, we also investigated patterns of association for local and regional factors with annual and inter-annual variation in abundance of 5 dominant marine estuarine-dependent fishes. The total amount of variation in fish abundance explained by environmental variables was 22.4%. After factoring out shared spatiotemporal variation (0.8%), our analysis showed that temporal components had an almost 5-fold greater contribution (28.0%) than spatial components (6.4%) in explaining the variation in abundance of the 5 species. Most of the variation across the temporal scale (58.5%) was associated with annual (from 0.5 to 1.3 yr) rather than multi-year oscillations (>2 yr). Such annual patterns were probably associated with adaptations of marine estuarine- dependent fishes for exploiting predictable pulses in seasonal productivity typically found in subtropical estuaries. In contrast, inter-annual variation in abundance occurring at a scale of 3 to 7 yr could be attributed to rainfall anomalies associated with El Niño Southern Oscillation (ENSO) events, whereas those occurring at a scale of 2 yr could be influenced by the Southern Annular Mode (SAM). Our findings corroborate the hypothesis that prevalent annual patterns of variation in the abundance of marine estuarine-dependent fishes are associated with predictable productivity pulses linked to the annual temperature regime, whereas inter-annual variations in fish abundance are associated with the influence of large-scale climatic phenomena. © Inter-Research 2012 · www.int-res.com.

De Souza Braz A.M.,University of Sao Paulo | Fernandes A.R.,Federal Rural University of Amazonia | Alleoni L.R.F.,University of Sao Paulo
Land Degradation and Development | Year: 2013

The conversion from forest to grassland is drastically changing soil characteristics in Amazon, leading to land degradation when it is poorly managed. Chemical and physical changes of a Typic Hapludox were evaluated as a function of the conversion (by means of fire) from forest to Brachiaria brizantha cultivation. Samples from the remaining forest were also sampled. Treatments were made to pastures eight (P8), thirteen (P13) and fifteen (P15) years after conversion, and to land under continuous grazing, and to a remaining forest area (control). The forest soil was more acidic than the pasture soils. Soil density and Ca+2 increased after the conversion, regardless of the period of grazing. Carbon stocks varied from 31·2tha-1 in the forest soil to 37·4 (P8), 33·5 (P13) and 30·7tha-1 (P15). Copyright © 2011 John Wiley & Sons, Ltd. © 2011 John Wiley & Sons, Ltd.

Fabris J.C.,Federal University of Espirito Santo | Marques G.T.,Federal Rural University of Amazonia
European Physical Journal C | Year: 2012

The d-dimensional scalar field action may be reduced, in the background geometry of a black hole, to a two-dimensional effective action. In the near-horizon region, it appears a gravitational anomaly: the energy-momentum tensor of the scalar field is not conserved anymore. This anomaly is removed by introducing a term related to the Hawking temperature of the black hole. Even if the temperature term introduced is not covariant, a gauge transformation may restore the covariance. We apply this method to compute the temperature of the dilatonic non-asymptotically flat black holes. We compare the results with those obtained through other methods. © 2012 Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica.

Marques G.T.,Federal Rural University of Amazonia | Rodrigues M.E.,Federal University of Espirito Santo
European Physical Journal C | Year: 2012

The conformal invariance of the Hawking temperature, conjectured for the asymptotically flat and stationary black holes by Jacobson and Kang, is semiclassically evaluated for a simple particular case of symmetrical spherically and non-asymptotically flat black hole. By using the Bogoliubov coefficients, the metric euclideanization, the reflection coefficient and the gravitational anomaly, as methods of calculating the Hawking temperature, we find that it is invariant under a specific conformal transformation of the metric. We briefly discuss the results for each method. © Springer-Verlag / Società Italiana di Fisica 2012.

Mitja D.,IRD Montpellier | Miranda I.S.,Federal Rural University of Amazonia
Weed Research | Year: 2010

To explain the dynamics of the weed vegetation in the Amazonian pastures after clearing of the rainforest, the diversity and floristic composition of 15 Brachiaria brizantha pastures and seven Panicum maximum pastures of various ages were studied. These pastures reflect the original forest, from which they retain a high species richness (from 20 to 73 species on average per 50 m2), a high proportion of forest woody species (from 26% to 65%) and rare species (>50%). The four ecological groups of plants, namely forest woody species, pioneer/secondary woody species, forest herbaceous species and secondary herbaceous species, are present in all pastures immediately after the clearing and burning of the forest and have to compete with the two sown forage species, B. brizantha and P. maximum. Because of its erect habit, P. maximum is rapidly invaded by secondary herbaceous weeds, whereas B. brizantha with its spreading habit slows down their proliferation, which therefore takes about 10 years to complete. The study showed the importance of factors such as the initial vegetation, manual-clearing practices, duration of cropping and species grown in influencing the floristic composition of the pastures and on the diversity of weeds. These results show the response of weeds faced with human disturbance. The results also demonstrate that farmers can manage pastures in a spirit of conservation of diversity or for weed control. © 2010 The Authors. Journal Compilation © 2010 European Weed Research Society.

Barbieri E.,Institute Pesca APTA SAA SP | Paes E.T.,Federal Rural University of Amazonia
Chemosphere | Year: 2011

The main purpose of the present study was to detect the acute toxicity of cadmium (Cd) in F. paulensis and to investigate its effect on oxygen consumption and ammonium excretion different salinities. First, we examined the acute toxicity of Cd in F. paulensis at 24, 48, 72, and 96-h lethal concentration (LC50). Cd was significantly more toxic at 5 salinity than at 20 and 36. The oxygen consumption and ammonium excretion were estimated through experiments performed on each of the twelve possible combinations of three salinities (36, 20 and 5), at temperature 20°C. Cd showed a reduction in oxygen consumption at 5 salinity, the results show that the oxygen consumption decreases with respect to the Cd concentration. At the highest Cd concentration employed (2mgL-1), the salinity 5 and the temperature at 20°C, oxygen consumption decreases 53.7% in relation to the control. In addition, after separate exposure to Cd, elevation in ammonium excretion was obtained, wish were 72%, 65% and 95% higher than the control, respectively. The results show that Cd is more toxic to F. paulensis at lower salinities. © 2011 Elsevier Ltd.

Araujo F.R.,Federal Rural University of Amazonia | Lopes M.A.,Federal Rural University of Amazonia
Biodiversity and Conservation | Year: 2012

Ethnobotanical information can clarify how dependent a community is on local plant resources and provide evidence about the consequences of resource exploitation. We performed a quantitative analysis on different aspects of knowledge and use of palms by the residents of the surrounding the Tucuruí Hydroelectric Power Station reservoir, eastern Amazonia, and their relationship with socioeconomic factors, adopting the methodology of consensus among informants. We based the study on accidental sampling of the 232 families and data were gathered through semi-structured forms. We evaluated correlations between the effective use and importance of species and the effect of socioeconomic factors on the knowledge and use of palms as cited by the informants. Informants know 27 species of palms and use 20 of these in eight different categories, the main ones being for food, utensils and construction. The species most widely used and cited as most important were Attalea speciosa, Oenocarpus bacaba, Euterpe oleracea, A. maripa and Socratea exorrhiza. For the informants, the value of a palm species is directly related to the different types of uses that it offers. The knowledge about palms is greater among farmers than fishermen and, when considering the medicinal aspect, it is greater among women than among men. © 2011 Springer Science+Business Media B.V.

Fernandes A.R.,Federal Rural University of Amazonia | de Matos G.S.B.,University of Amazon
Revista Brasileira de Fruticultura | Year: 2013

The peach palm (Bactrisgasipaes Kunth) cultivation has increased according to increasing demand of its products; however there are few studies, as well as knowledge about nutritional requirement of this specie. The objective was to evaluate the nutritional symptoms deficiencies, dry matter production, nutrient content and accumulation in peach palm seedlings, according to macronutrients and Na omission. The experiment was realized in greenhouse in randomized blocks design. The treatments were: complete nutrient solution; omission of N, P, K, Ca, Mg, S and Na. The omissions promoted morphological alterations in shoots and roots characterized by visual symptoms easily interpretable. The elements N, P and K were the most limiting and the S and Na were the least limiting to leaves, stem, roots, shoots and total dry matter. The shoot/root relationship was K>Mg>Ca=P and P=complete=S=Na>N and the relative growth was complete>Na>S>Ca>Mg>K>P>N. The nutrient contents and accumulations follow mainly the sequence N>K>Ca>P>Mg>S>Na. The omissions caused symptoms typical to those observed in other species. The dry matter and relative growth were most limiting by N, P and K. The K, Mg, Ca and P were most limiting to roots and others nutrients were most limiting to shoots. The Na was important to peach palm, in the absence of Na of growth on reduced 10.6%. The nutrients in higher amounts in the specie are N, K and Ca.

Loading Federal Rural University of Amazonia collaborators
Loading Federal Rural University of Amazonia collaborators