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Duque de Caxias, Brazil

Dos Dourado E.C.S.,Instituto Federal do Maranhao | Nunes J.L.S.,Federal University of Maranhao | Piorski N.M.,Federal University of Maranhao
Cybium | Year: 2015

Acestrorhynchus falcatus (Bloch, 1794) and A. heterolepis (Cope, 1878) are two species frequently found in rivers from Baixada Maranhense, Maranhão State, northeastern of Brazil. The ecomorphological adaptations of these species were studied based on a collection of 445 specimens using morphometric tools. Seventeen landmarks were defined on the lateral side of the individuals and digitalized by the TPS Dig program. The data matrix was submitted to a Relative Warps Analysis (RWA) and a Canonical Variables Analysis (CVA) in order to identify the morphological patterns of each species. In addition, observations about the digestive tract of each species and diet comparison through the feeding ecology are provided. The main differences between A. falcatus and A. heterolepis, as indicated by the analysis, were associated with swimming agility and prey size. A. heterolepis has a shallow body, close to a fusiforme profile, deep caudal fin and low caudal peduncle. In contrast, A. falcatus possesses a shorter head and a lower caudal fin, better adapted to capture small preys and to live in mid-lower region of the water column. According to these traits, the two species probably avoid competition by catching prey of different sizes and using distinct strategies for this procedure. © SFI. Source

This paper presents a comparative chemical and mineralogical study of birnessite (BIR-AZ) collected from Azul mine (Carajás Province, Brazil) and its synthetic analogous synthesized by sol-gel method. The products were characterized by X-ray diffraction, FT-Raman spectroscopy, thermal analysis (TG-DTA), scanning electron microscopy (SEM) and ICP-MS techniques. The results obtained confirm the presence of well-defined layer structures having monoclinic system, C2/m space group and the unit cell parameters are: BIR-AZ, a = 5.148 Å; b=2.843 Å, c=7.175 Å, and = 100.75°; K-OL-SG, a = 5.150 Å;β= 2.846 Å, c = 7.214 Å, and = 101.29°. The birnessite from Azul mine ores shows thermal stability up to 600 °C, whereas its synthetic analogous, above 900 °C. FT-Raman bands at 635, 570 and 410 cm-1 were identified and attributed to the Mn-O and K-O bond deformations in the birnessite structure. SEM images reveals that the manganese oxide mineral consist of platy packed particles of about 1 to 5 μm. By contrast, the morphology of the synthetic compound displays randomly arranged globules (<1 μm). Source

Marques L.J.P.,Instituto Federal do Maranhao | Bianco S.,Sao Paulo State University | Filho A.B.C.,Sao Paulo State University | Bianco M.S.,Sao Paulo State University
Planta Daninha | Year: 2016

Eggplants are vegetables of great importance in the South and Southeast regions of Brazil, which are subject to interference from weeds. In order to collaborate with weed management in this vegetable, this study was carried out to determine the periods of weed interference in growing eggplants. The study was conducted in the Brazilian municipality of Jaboticabal, SP, at the Faculty of Agricultural and Veterinary Sciences, UNESP [Universidade Estadual Paulista “Júlio de Mesquita Filho” (São Paulo State University)], in the period from February to July 2013. The experiment was arranged in a randomized block design with 22 treatments, three replications divided in 11 periods of coexistence and weed control with eggplants: 14, 28, 42, 56, 70, 84, 98, 112, 126, 140 and 154 days after transplanting (DAT). In each treatment, a phytosociological study was carried out to identify the important species of weeds in eggplant crops. The main weeds were Eleusine indica, Nicandra physaloides, Portulaca oleracea and Cyperus rotundus due to their high relative importance. The interference of these weeds caused losses of up to 96% to the standard commercial fruit yield. The period before interference was 6 DAT and the total period of interference was 102 DAT. Therefore, it is concluded that after the initial six days after transplanting eggplants, the crop should be free of weeds within the next 96 days. © 2016, Sociedade Brasileira da Ciencia das Plantas Daninha. All Rights Reserved. Source

Figueira B.A.M.,Federal University of Para | Angelica R.S.,Federal University of Para | Costa M.L.,Federal University of Para | Poellmann H.,Martin Luther University of Halle Wittenberg | Mercury J.M.R.,Instituto Federal do Maranhao
Ceramica | Year: 2013

The tunnel-structure manganese oxide minerals, hollandite (Apuí, Amazonas state, Brazil, area in prospection) and cryptomelane (Urucum, Mato do Sul Grosso state, Brazil) were isolated and characterized chemical, mineralogical, thermal and morphologically. The following techniques were employed: scanning electron microscopy-EDS, thermal analysis (DTA-TG), X-ray diffraction with continuous-heating. The empirical formula, were calculated on the basis 16 oxygen gave as (Ba0.18K0.12Ca 0.02Pb0.04)0.76 (Mn6.34Al 0.61Si0.25Fe0.24Ti 0.08)7.54O160.4H2O for hollandite and (K0.9Na0.04Ca0.03Sr0.04) 1.04 (Mn7.38Fe0.28Al 0.27Si0.08)8O16 for cryptomelane. The SEM investigations allowed the differentiation of the morphologies for hollandite and cryptomelane. The minerals were thermally treated among 100-900 °C and X-ray diffraction patterns in situ were collected. The analysis of X-ray diffractions experiments showed that a hollandite-crytomelane mineral has a thermal stability up to 900 °C. Source

Cintra C.L.D.,Av. Getulio Vargas 04 | Cintra C.L.D.,University of Washington | Paiva A.E.M.,Instituto Federal do Maranhao | Baldo J.B.,University of Washington
Ceramica | Year: 2014

In this study it is presented some relevant properties of light masonry mortars composed of cement, lime, washed river sand, vermiculite and recycled rubber aggregates from wasted tires. The properties of these mortars were comparatively evaluated to similar ones using the same components except recycled rubber aggregates. The properties in the fresh condition such as; consistency, mass density, mixing water, entrained air content, final set time and the properties in the hardened state such as apparent density, compressive strength and adherence tensile strength, were the comparison parameters. The results indicate that the properties in fresh condition of the rubber containing mortars were similar to those of mortars without rubber aggregates. On the other hand, in the hardened condition the axial compressive strength and adherence tensile strength of the rubber containing mortars were superior to those of mortars without rubber aggregates. The apparent densities of the rubber containing mortars were bigger than the ones without rubber aggregates, however, they still could be categorized as light weight mortars, fully satisfying the Brazilian standards requirements. These findings indicate that the vermiculite and rubber combination are a feasible, cheaper and sustainable alternative for light weight masonry mortars compared to the ones containing only vermiculite. Source

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