19 research outputs found

    Eficiência da bioadição na remoção de matéria orgânica em sistemas aquaculturais

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    Several techniques are currently used to treat effluents. Bioaugmentation is a new bioremediation strategy and has been employed to improve effluent quality by treating the water during the production process. This technology consists basically of the addition of microorganisms able to degrade or remove polluting compounds, especially organic matter and nutrients. The objective of this study was to assess the effects of bioaugmentation on some parameters of organic matter and on the performance of juvenile tilapias in an intensive aquaculture production system. The combination of two bacterial consortiums in a complete randomized design was employed in a factorial analysis with two factors. Statistical differences between treatments were analyzed by the analysis of variance (ANOVA) and Tukey test at the 5% level. One of the treatments, heterotrophic bacterial supplementation, was able to reduce biochemical oxygen demand (BOD) by 23%, dissolved organic carbon (DOC) by 83.7% and phytoplanktonic biomass by 43%. On the other hand, no damage was done to either the physical-chemical indicators of water quality or to the growth performance of juvenile tilapias assessed in this study.Existem diversas tecnologias para tratamento de efluentes, o processo de bioadição consiste em uma vertente da biorremediação e tem sido empregado na melhoria da qualidade dos efluentes através do tratamento da água de produção. Esta tecnologia consiste basicamente na adição de microrganismos com a capacidade de degradar ou remover compostos poluentes, especialmente matéria orgânica e nutrientes. Este estudo objetivou avaliar os efeitos da suplementação de composto bioativo sobre alguns parâmetros de matéria orgânica e de desempenho de juvenis de tilápias em um sistema intensivo de produção aquacultural. Foi empregada a combinação de dois consórcios bacterianos em delineamento inteiramente aleatorizado, em um esquema fatorial com dois fatores. As diferenças estatísticas entre os tratamentos foram analisadas por meio da análise de variância (ANOVA) e do teste de Tukey ao nível de 5%. Verificou-se neste estudo, que a bioadição heterotrófica foi capaz de reduzir em 23% a demanda bioquímica de oxigênio (DBO); em 83,7%, o carbono orgânico dissolvido (COD); e em 43%, a biomassa fitoplanctônica. Por outro lado, não se observou nenhum prejuízo com relação aos parâmetros físico-químicos de qualidade de água bem como ao desempenho de crescimento para juvenis de tilápias avaliados neste estudo.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

    Effect of the composite photoactivation mode on microtensile bond strength and Knoop microhardness

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    Objective. This study evaluated the effect of the composite photoactivation mode on microtensile bond strength and Knoop microhardness. Methods. Standard class I cavities (3 x 4 x 3 mm) were restored with two adhesives systems, Single Bond (SB) and Clearfil SE Bond (CE), and the TPH composite. The photoactivation of the composite was carried out using three modes: Conventional (CO: 400 mW/cm(2) x 40s), Soft-Start (SS: 100 mW/cm(2) x 10s + 600 mW/cm(2) x 30s) and Pulse-Delay (PD: 100 mW/cm(2) x 3s + 3 min wait + 600 mW/cm(2) x 37 s). For the microtensite test, beams obtained from the buccal wall bond interface were tested under tension at 0.5 mm/min crosshead speed until failure. For the microhardness test, the restorations were sectioned in the mesio-distal direction and indentations were made on the internal composite surface of each half at three different depths. Data of two tests were analyzed using two-way ANOVA and LSMeans (alpha = 0.05). Results. In the microtensile test, SS presented the highest values. PD presented intermediate values without differing significantly from the other modes. For adhesives, SB presented the highest values. In the microhardness test, PD presented the highest values, differing significantly from SS. CO presented intermediate values but without any statistical difference from the others. The SS-CE interaction presented the lowest values with statistical differences from all the others. Significance. By the SS technique, the highest bond strength was obtained. However, this technique made it possible for the adhesive system to intervene with the hardness of the composite. (c) 2005 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.22320321

    Fracture resistance of premolars with bonded class II amalgams

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    This study evaluated the fracture resistance of maxillary premolars with MOD cavity preparation and simulated periodontal ligament. The teeth were restored with silver amalgam (G1), Scotchbond Multi-Purpose Plus and silver amalgam (G2) and Panavia F and silver amalgam (G3). After restorations were made, the specimens were stored at 37degreesC for 24 hours at 100% humidity and submitted to the compression test in the Universal Testing Machine (Instron). The statistical analysis of the results (ANOVA and Tukey Test) revealed that the fracture resistance of group 2 (G2=105.720 kgF) was superior to those of groups 1 (G1=72.433 kgF) and 3 (G3=80.505 kgF) that did not differ between them.27434935

    Quantifying intraclass correlations for nonnegative traits

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    Fracture resistance of teeth restored with the bonded amalgam technique

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    This study evaluated the fracture resistance of maxillary premolars; with MOD Class II cavity preparations restored with silver amalgam (Gl), Scotchbond Multi Purpose Plus and silver amalgam (G2) and Panavia F and silver amalgam (G3). After the restorations were made, the specimens were stored at 37 degreesC for 24 hours at 100% humidity and submitted to the compression test. Statistical analysis of the data (ANOVA and Tukey Test) revealed no significant differences among the three groups that were studied.26551151

    Negative variance components for non-negative hierarchical data with correlation, over-, and/or underdispersion

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    © 2016 Informa UK Limited, trading as Taylor & Francis Group. The concept of negative variance components in linear mixed-effects models, while confusing at first sight, has received considerable attention in the literature, for well over half a century, following the early work of Chernoff [7] and Nelder [21]. Broadly, negative variance components in linear mixed models are allowable if inferences are restricted to the implied marginal model. When a hierarchical view-point is adopted, in the sense that outcomes are specified conditionally upon random effects, the variance–covariance matrix of the random effects must be positive-definite (positive-semi-definite is also possible, but raises issues of degenerate distributions). Many contemporary software packages allow for this distinction. Less work has been done for generalized linear mixed models. Here, we study such models, with extension to allow for overdispersion, for non-negative outcomes (counts). Using a study of trichomes counts on tomato plants, it is illustrated how such negative variance components play a natural role in modeling both the correlation between repeated measures on the same experimental unit and over- or underdispersion.peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=cjas20status: publishe

    Effects of glycerol on the metabolism of broilers fed increasing glycerine levels

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    This study evaluated the metabolic response of broilers fed diets containing increasing crude glycerine levels in two bioassays. Birds were house in metabolic cages, and were distributed according to a completely randomized experimental design with five treatments of 4 replicates each (1st assay: 5 birds/ cage; 2nd assay: 1-20 days = 8 birds/ cage, and 21-42 days = 4 birds/cage). Treatments consisted of a control diet based on corn and soybean meal, and four other diets containing 2.5%, 5.0%, 7.5% and 10.0% glycerine derived from biodiesel. In experiment I, there was no effect (p&gt;0.05) of glycerol level on liver weight or blood parameters. Serum blood glycerol levels of the birds fed 10% crude glycerine increased during the first nine days of diet intake (p<0.05). In experiment II, water intake increased (p<0.05) in the birds fed 7.5 and 10.0% crude glycerine at 4 and 8 days of age. Feed intake increased (p<0.05) on days 8 and 12 in birds fed 2.5 and 7.5% glycerine. Fecal moisture increased (p<0.05) in birds fed diets with 5.0, 7.5, and 10.0% crude glycerine on days 16 and 20. Ileal content moisture was not different (p&gt;0.05) among treatments when birds were 42 days old. High dietary glycerine levels may induce metabolic change in broilers, such as increased blood glycerol level, water intake and fecal moisture

    Influence of photo-curing distance on bond strength and nanoleakage of self-etching adhesive bonds to enamel and dentin

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    Objectives. To assess the influence of light-curing unit tip distance on the microtensile bond strength (mu TBS) and nanoleakage of self-etching adhesives to enamel and dentin. Materials and methods. Flat buccal surfaces were prepared on 198 bovine incisors. The teeth were randomly assigned into nine groups for mu TBS (n = 8) and nanoleakage (n = 3) testing according to the adhesive system (Clearfil Protect Bond, Clearfil Tri-S Bond or One Up Bond F Plus) and distance from the light-curing tip (0, 3 or 6 mm). The bonded samples were tested in tension (0.5 mm/min) and nanoleakage was analyzed using SEM. Results. Clearfil Protect Bond exhibited the highest tensile strength on both enamel and dentin. Leakage was higher in samples exposed at a distance of 6 mm on enamel and 0 mm on dentin. One Up Bond F Plus experienced the greatest amount of nanoleakage on both substrates. Conclusions. Light-curing unit distance did not influence the mu TBS of the adhesives, but nanoleakage increased on enamel samples when photoactivation occurred at a distance of 6 mm.72211311
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