192 research outputs found

    A new species of Corydoras Lacépède (Siluriformes: Callichthyidae) from the Rio Tapajós basin and its phylogenetic implications

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    A new species of Corydoras is described from tributaries of the rio Arinos, rio Teles Pires and rio Preto, all in the rio Tapajós basin. The new species is a member of a group that includes 36 species with spots on the body. Within this group, the new species can be readily distinguished by having a smaller dorsal-fin spine than the first three subsequent soft dorsal-fin rays; pectoral, pelvic and anal fins hyaline; dorsal-fin interradial membrane hyaline; rounded spots on trunk restricted to dorsolateral body plates and dorsal portion of ventrolateral body plates, not reaching the base of pelvic and anal fins. The new species can be further distinguished from Corydoras xinguensis by having spots with diffuse edges, and from all other species of spotted Corydoras except C.multimaculatus, by the absence of ventral platelets. A phylogenetic analysis recovered the new species plus Corydoras metae and C.araguaiensis in a clade sharing the presence of a pointed process on the maxilla for insertion of the retractor tentaculi muscle. In addition, the presence in the new species of an elongated anterior portion of the mesethmoid and a triangular uncinate process of the epibranchial 3 suggests a close relationship with Corydoras metae.Uma nova espécie de Corydoras é descrita dos tributários dos rios Arinos, Teles Pires e Preto, bacia do rio Tapajós. A nova espécie é membro de um grupo com pontilhados no corpo que inclui 36 espécies. Dentro desse grupo, a nova espécie pode ser facilmente distinguida pelo espinho dorsal menor que os três primeiros raios ramificados da nadadeira dorsal; nadadeiras peitorais, pélvicas e anal hialinas; membranas inter-radiais da nadadeira dorsal hialina; presença de pontilhados redondos no tronco restritas as placas dorsolaterais do corpo e porções dorsais das placas ventrolaterais não alcançando a base das nadadeiras pélvicas e anal. A nova espécie pode ser distinguida de Corydoras xinguensis por pontilhados com margens difusas e das demais espécies de Corydoras com pontilhado, exceto em C.multimaculatus, pela ausência de pequenas placas ventrais. Uma análise filogenética recuperou a nova espécie mais Corydoras metae e C.araguaiensis em um agrupamento compartilhando a presença de um processo pontiagudo para inserção do músculo retractor tentaculi no maxilar. A porção anterior do mesetmóide alongada e o processo uncinado do epibranquial 3 triangular indicam uma relação mais próxima com Corydoras metae

    Microbial activity in a degraded Latosol treated with sewage sludge

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    The degraded soil shows, in general, poor biological activity, considering its physical characteristics, low fertility and organic matter, mainly due to removal or degradation of its superficial layer. The sewage sludge, due to its high content of easily decomposed organic matter can be an alternate source of organic residues and combined to its high content of the principal nutrients for the plants can be an important factor to promote biological activities in degraded soil. In order to study the actions of the sewage sludge in the recovery of a degraded Latosol, the carbon in the microbial biomass (Cmic), the carbon released CO2 (C-CO2) and the relation between microbial and organic carbon (Cmic/Corg) were used as indicators of the effects. To do so, two doses (30 and 60 Mg ha-1) of sewer slime applied in topdressing and incorporated together with a mineral fertilizer treatment, using the eucalyptus as a test crop. A completely randomized design with 4 treatments and 4 repetitions was used. The sewage sludge promoted increase of liberated C-CO2 and the Cmic, which constitute the adequate quality indicators for monitoring the soil recovery.Em geral, os solos degradados se apresentam com fraca atividade biológica, tendo em vista suas características físicas, baixa fertilidade e teores de matéria orgânica, devido principalmente à remoção ou degradação de sua camada superficial. O elevado teor de matéria orgânica facilmente decomposta do lodo de esgoto, que é uma fonte alternativa de resíduos orgânicos, aliado à sua elevada taxa dos principais elementos nutrientes às plantas, pode ser um fator importante do retorno ou incremento da atividade biológica dos solos degradados. Com a finalidade de se estudar as ações do lodo de esgoto na recuperação de um Latossolo degradado, utilizaram-se, como indicadores dos efeitos, o carbono na biomassa microbiana (Cmic), o carbono do CO2 (C-CO2) liberado e a relação entre o carbono microbiano e o carbono orgânico (Cmic/Corg); para isto, foram definidas duas doses de lodo de esgoto aplicadas em cobertura e incorporada, de 30 e 60 Mg ha-1 à base seca, juntamente com um tratamento com fertilizante mineral, utilizando-se o eucalipto como cultura teste. O delineamento experimental foi o inteiramente casualizado, com 4 tratamentos e 4 repetições. O lodo de esgoto promove aumento do C-CO2 liberado e do Cmic, os quais constituem indicativos de qualidade adequados ao monitoramento da recuperação do solo.19519

    Manejo da irrigação no algodoeiro herbáceo cultivado na região semiárida, cultivares BRS 430 B2RF e BRS 368RF.

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    O manejo da irrigação na cultura do algodão constitui uma técnica muito importante do ponto de vista econômico e ambiental, possibilitando reduzir o risco de perda de safra, o aumento da produtividade, a melhoria na qualidade de fibra e, principalmente, a eficiência no uso da água, já que a região Nordeste é marcada pela escassez de chuvas, tornando imperativo a utilização da irrigação com uma alta eficiência, de modo a aproveitar melhor a água disponível. Nesse contexto, o trabalho teve como objetivo, avaliar a utilização de três métodos de manejo de irrigação visando a obtenção de altos rendimentos e uma maior eficiência de uso da água

    Warm stellar matter with deconfinement: application to compact stars

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    We investigate the properties of mixed stars formed by hadronic and quark matter in β\beta-equilibrium described by appropriate equations of state (EOS) in the framework of relativistic mean-field theory. We use the non- linear Walecka model for the hadron matter and the MIT Bag and the Nambu-Jona-Lasinio models for the quark matter. The phase transition to a deconfined quark phase is investigated. In particular, we study the dependence of the onset of a mixed phase and a pure quark phase on the hyperon couplings, quark model and properties of the hadronic model. We calculate the strangeness fraction with baryonic density for the different EOS. With the NJL model the strangeness content in the mixed phase decreases. The calculations were performed for T=0 and for finite temperatures in order to describe neutron and proto-neutron stars. The star properties are discussed. Both the Bag model and the NJL model predict a mixed phase in the interior of the star. Maximum allowed masses for proto-neutron stars are larger for the NJL model (1.9\sim 1.9 M_{\bigodot}) than for the Bag model (1.6\sim 1.6 M_{\bigodot}).Comment: RevTeX,14 figures, accepted to publication in Physical Review

    An Innovative Photoreactor, FluHelik, To Promote UVC/H2O2 Photochemical Reactions: Tertiary Treatment of an Urban Wastewater

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    This is the accepted manuscript of the following article: Espíndola et al. Science of the Total Environment, 2019, 667, 197-207. https://doi.org/10.1016/j.scitotenv.2019.02.335An innovative photoreactor, FluHelik, was used to promote the degradation of contaminants of emerging concern (CECs) by a photochemical UVC/H2O2 process. First, the system was optimized for the oxidation of a model antibiotic, oxytetracycline (OTC), using both ultrapure water (UPW) and a real urban wastewater (UWW) (collected after secondary treatment) as solution matrices. Following, the process was evaluated for the treatment of a UWW spiked with a mixture of OTC and 10 different pharmaceuticals established by the Swiss legislation at residual concentrations (∑CECs <660 μg L−1). The performance of the FluHelik reactor was analyzed both at lab and pre-pilot scale in multiple and single pass flow modes. The efficiency of the FluHelik photoreactor, at lab-scale, was evaluated at different operational conditions (H2O2 concentration, UVC lamp power (4, 6 and 11 W) and flow rate) and further compared with a conventional Jets photoreactor. Both photoreactors exhibited similar OTC removal efficiencies at the best conditions; however, the FluHelik reactor showed to be more efficient (1.3 times) in terms of mineralization when compared with the Jets reactor. Additionally, the efficiency of the UVC/H2O2 photochemical system using the FluHelik photoreactor in reducing the toxicity of the real effluent containing 11 pharmaceuticals was evaluated through zebrafish (Danio rerio) embryo toxicity bioassays. FluHelik scale-up from laboratory to pre-pilot to promote UVC/H2O2 photochemical process proved to be feasibleThis work was financially supported by: Associate Laboratory LSRE-LCM - UID/EQU/50020/2019 - funded by national funds through FCT/MCTES (PIDDAC). V.J.P. Vilar acknowledges the FCT Investigator 2013 Programme (IF/00273/2013). J.C.A. Espíndola acknowledges CNPq (Brazil) for his scholarship (205781/2014-4). R. Montes, R. Rodil and J.B. Quintana acknowledge the financial support of Spanish "Agencia Estatal de Investigación" (ref. CTM2017-84763-C3-R-2) and Xunta de Galicia (ref. ED431C2017/36), both confounded by FEDER/ERDFS

    Structural and Spectroscopic Properties of Two New Isostructural Complexes of Lapacholate with Cobalt and Copper

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    The molecular structures of two isostructural complexes of lapacholate (Lap) anion and dimethylformamide (DMF), M(Lap)2(DMF)2 with M: Co Cu, were determined by X-ray diffraction methods. The substances crystallize in the triclinic space group P1 with one molecule per unit cell and cell constants a = 7.7591(3), b = 10.3560(3), c = 11.2224(4) A, α = 95.110(2), β = 94.310(2), and γ = 107.704(2)◦ for the Co complex and a = 7.9308(2), b = 10.0033(4), c = 10.7508(4), α = 97.387(2), β = 93.621(2), and γ = 103.980(2)◦ for the Cu complex. The structures were solved from 2933 (Co) and 2888 (Cu) reflections with I > 2σ (I) and refined by full matrix least squares to agreement R1-factors of 0.041 (Co) and 0.033 (Cu). The metal M(II) ion is sited on a crystallographic inversion center in a MO6 distorted octahedral environment. This ion is coordinated equatorially to two lapacholate anions through their adjacent carbonyl and phenol oxygen atoms [M–O bond distances of 2.134(1) and 2.008(1) A˚ (Co) and 2.301(1) and 1.914(1) A (Cu)] and axially to two DMF molecules through oxygen atoms [M–O bond lengths of 2.143(1) ˚ A (Co) and 2.069(1) ˚ A (Cu)]. The solid state IR transmittance and solution electronic absorption spectra of both Co and Cu ˚ compounds are also reported and compared to each other and to the corresponding spectra of other members of the lapacholate metal family of complexes.Instituto de Física La Plat

    Rendimento agronômico de consórcios entre pimentão e feijão-vagem arbustivo em sistema orgânico de cultivo.

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    bitstream/CNPAB-2010/34643/1/cot106.pdfParcerias: UFRRJ

    Not Only Toxic but Repellent: What Can Organisms’ Responses Tell Us about Contamination and What Are the Ecological Consequences When They Flee from an Environment?

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    The ability of aquatic organisms to sense the surrounding environment chemically and interpret such signals correctly is crucial for their ecological niche and survival. Although it is an oversimplification of the ecological interactions, we could consider that a significant part of the decisions taken by organisms are, to some extent, chemically driven. Accordingly, chemical contamination might interfere in the way organisms behave and interact with the environment. Just as any environmental factor, contamination can make a habitat less attractive or even unsuitable to accommodate life, conditioning to some degree the decision of organisms to stay in, or move from, an ecosystem. If we consider that contamination is not always spatially homogeneous and that many organisms can avoid it, the ability of contaminants to repel organisms should also be of concern. Thus, in this critical review, we have discussed the dual role of contamination: toxicity (disruption of the physiological and behavioral homeostasis) vs. repellency (contamination-driven changes in spatial distribution/habitat selection). The discussion is centered on methodologies (forced exposure against non-forced multi-compartmented exposure systems) and conceptual improvements (individual stress due to the toxic effects caused by a continuous exposure against contamination-driven spatial distribution). Finally, we propose an approach in which Stress and Landscape Ecology could be integrated with each other to improve our understanding of the threat contaminants represent to aquatic ecosystems.Versión del edito
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