146 research outputs found

    A bounded upwinding scheme for computing convection-dominated transport problems

    Get PDF
    A practical high resolution upwind differencing scheme for the numerical solution of convection-dominated transport problems is presented. The scheme is based on TVD and CBC stability criteria and is implemented in the context of the finite difference methodology. The performance of the scheme is investigated by solving the 1D/2D scalar advection equations, 1D inviscid Burgers’ equation, 1D scalar convection–diffusion equation, 1D/2D compressible Euler’s equations, and 2D incompressible Navier–Stokes equations. The numerical results displayed good agreement with other existing numerical and experimental data

    Occurrence of Salmonella spp. in the broiler production chain

    Get PDF
    ABSTRACT Brazilian chicken meat is exported to more than 150 countries and consumed by consumer markets that demand high quality and food safety, thus, requiring very strict control of pathogens present in food to guarantee these rigorous safety standards. This study evaluates the reports from the Salmonella spp. Control and Monitoring Program of the Brazilian Ministry of Agriculture, Livestock and Food Supply of seven slaughterhouses inspected by the Federal Inspection Service from the western region of Paraná state, Brazil, from March 2017 to February 2019. The broiler litter swab and carcass analyses revealed a Salmonella spp. positivity ratio of 5.9% (19/319) and 23.5% (75/319), respectively. The concomitant presence of Salmonella spp. in the broiler litter swab and chicken carcasses occurred in 58% of the positive samples. The most frequently isolated serovar in the carcasses was Salmonella Heidelberg (85.3%) followed by Salmonella spp. (10.6%). During slaughter, carcass positivity to Salmonella spp. was significantly different (p=0.047) between the first (19.6%) and the second (29.4%) shifts. The results alert for the possibility of carcass contamination during slaughtering and, therefore, more stringent hygiene measures between shifts must be implemented to mitigate carcass contamination

    Degradação Fotocatalítica De Pesticida Organofosforado De Efluente Agrícola Por Tio2 Imobilizado Sob Radiação Solar

    Get PDF
    This paper describes solar heterogeneous photocatalysis using immobilized TiO2 applied in the treatment of agricultural waste resulting from the application of commercial formulations of methyl parathion. The disappearance of the insecticide, as well as the formation of its metabolite, was monitored by high-performance liquid chromatographytandem mass spectrometry (LC-MS/MS), while mineralization efficiency was monitored by measurements of total organic carbon (TOC). Toxicity studies were performed using the microcrustacean Artemia salina. The TOC removal efficiency by photocatalytic process was 48.5%. After 45 minutes of treatment, the removal efficiency of methyl parathion was 90%, being completely mineralized at the end of treatment. The formation and removal of the metabolite methyl paraoxon was observed during the photocatalytic process. The photocatalytic treatment resulted in increased microcrustacean mobility, indicating a reduction of acute toxicity. © 2016, Institute for Environmental Research in Hydrographic Basins (IPABHi). All rights reserved.11477878

    Grapevine yield prediction using image analysis - improving the estimation of non-visible bunches

    Get PDF
    Yield forecast is an issue of utmost importance for the entire grape and wine sectors. There are several methods for vineyard yield estimation. The ones based on estimating yield components are the most commonly used in commercial vineyards. Those methods are generally destructive and very labor intensive and can provide inaccurate results as they are based on the assessment of a small sample of bunches. Recently, several attempts have been made to apply image analysis technologies for bunch and/or berries recognition in digital images. Nonetheless, the effectiveness of image analysis in predicting yield is strongly dependent of grape bunch visibility, which is dependent on canopy density at fruiting zone and on bunch number, density and dimensions. In this work data on bunch occlusion obtained in a field experiment is presented. This work is set-up in the frame of a research project aimed at the development of an unmanned ground vehicle to scout vineyards for non-intrusive estimation of canopy features and grape yield. The objective is to evaluate the use of explanatory variables to estimate the fraction of non-visible bunches (bunches occluded by leaves). In the future, this estimation can potentially improve the accuracy of a computer vision algorithm used by the robot to estimate total yield. In two vineyard plots with Encruzado (white) and Syrah (red) varieties, several canopy segments of 1 meter length were photographed with a RGB camera and a blue background, close to harvest date. Out of these images, canopy gaps (porosity) and bunches’ region of interest (ROI) files were computed in order to estimate the corresponding projected area. Vines were then defoliated at fruiting zone, in two steps and new images were obtained before each step. Overall the area of bunches occluded by leaves achieved mean values between 67% and 73%, with Syrah presenting the larger variation. A polynomial regression was fitted between canopy porosity (independent variable) and percentage of bunches not occluded by leaves which showed significant R2 values of 0.83 and 0.82 for the Encruzado and Syrah varieties, respectively. Our results show that the fraction of non-visible bunches can be estimated indirectly using canopy porosity as explanatory variable, a trait that can be automatically obtained in the future using a laser range finder deployed on the mobile platforminfo:eu-repo/semantics/publishedVersio

    i-Farm: A exploração vitícola inteligente da sociedade da informação e do conhecimento

    Get PDF
    Neste trabalho explora-se o potencial das mais recentes inovações tecnológicas disponíveis no mercado para construir a i-Farm, a exploração agrícola inteligente da sociedade da informação e do conhecimento, aplicada à viticultura. A i-Farm, projecto financiado pelo Programa DEMTEC da Agência de Inovação, aplica ao nível da exploração agrícola, o potencial da utilização integrada de soluções móveis, redes de sensores, comunicações sem fios e imagens aéreas materializado num sistema de informação geo-referenciado que apoia, no campo ou no escritório, a tomada de decisão do empresário agrícola em tempo real. A i-Farm é suportada por um sistema de informação integrando de forma modular múltiplas funcionalidades, tais como sensores ambientais, fito-sensores, câmaras de vídeo e fotográficas, assistentes pessoais digitais, etc., acessíveis num ponto de acesso único na Web. A lógica modular que a i-Farm adopta permite assegurar a possibilidade de, a prazo, agregar ao sistema de informação sistemas de apoio à decisão de natureza diversa, como sejam ferramentas de apoio à gestão da rega, previsão de ocorrência de problemas com pragas e doenças, cálculo de necessidades de nutrientes, previsão de colheita, etc. Este sistema consegue “falar” com os restantes sistemas de informação sectoriais existentes na exploração, com sejam a gestão de stocks, facturação, contabilidade, recursos humanos, etc. Por último, sendo suportado pelas tecnologias Internet, assegura a possibilidade de recolher, armazenar e disponibilizar informação com origem no ambiente externo da exploração, incluindo informação de mercado, legal, administrativa, etc. O acesso à informação é efectuado numa interface amigável, sempre em ambiente Web, para duas plataformas distintas - computadores de secretária / portáteis e assistentes pessoais digitais com ligação à Internet, com ou sem fios. No caso dos assistentes pessoais digitais, o acesso à Internet sem fios permitirá o acesso através da própria rede local sem fios da i-Farm na exploração oferecendo, assim, a possibilidade do próprio técnico / empresário aceder ao sistema quando está a realizar a sua visita ao terrenoinfo:eu-repo/semantics/publishedVersio

    New insights on the effects of formulation type and compositional mixtures over the antioxidant and cytotoxic activities of dietary supplements based-on hepatoprotective plants

    Get PDF
    Artichoke (A), borututu (B) and milk thistle (M) are included in several supplements to provide beneficial effects. Different formulations (infusions, pills and syrups), as also different proportions of A, B and M (1:1:1, 2:1:1, 1:2:1, 1:1:2) within each formulation were assayed to optimize the desired benefits. The antioxidant activity, anti-hepatocellular carcinoma activity, hepatotoxicity and bioactive compounds contents were evaluated. Syrups tended to be the formulation with highest antioxidant activity and total phenolics and flavonoids content; otherwise, pills were the worst formulation. In what concerns A:B:M ratios, the results did not reveal so pronounced differences. None of the assayed mixtures resulted to be toxic (up to the maximum assayed dose) for liver primary cells (PLP2), but some samples, especially infusions, showed toxicity for the hepatocellular carcinoma cell line (HepG2). With no exception, the mixtures for all formulations gave synergistic effects in antioxidant activity, when compared to the activity of single plants.The authors are grateful to Fundação para a Ciência e a Tecnologia (FCT, Portugal) for financial support to CIMO (strategic project PEst-OE/AGR/UI0690/2011). J.C.M. Barreira and R.C. Calhelha thank FCT, POPH-QREN and FSE for their grants (SFRH/BPD/68344/2010 and SFRH/BPD/72802/2010, respectively). L. Barros thanks “Compromisso para a Ciência 2008” for her contract

    Bioactivity of Methanolic and Aqueous Extracts of Laurus nobilis L. from Different Origins

    Get PDF
    Laurus nobilis L. (Laureaceae), commonly known as laurel, is a native plant from the Mediterranean region. Most widely used as culinary spice, it is also consumed as infusion to treat some gastrointestinal problems (Dall’Acqua et al., 2009) and has been reported as a rich source of bioactive compounds namely, essential oils and phenolic compounds (Dadalioğlu et al., 2004; Dias et al., 2013). In the present work, methanolic and aqueous extracts of wild and cultivated L. nobilis were studied for their in vitro antitumor (against five different human tumor cell lines) and antimicrobial (antibacterial and antifungal) activities. Furthermore, a two-dimensional principal component analysis (PCA) was used to understand how each extract act differentially towards specific bacterial and fungal species, and also selected human tumor cell lines. Both assayed factors, origin (wild or cultivated) and extract type (methanolic or aqueous) act in a differentiated manner; i.e., the same evaluated parameter gave sometimes statistically significant differences regarding laurel origin, but no effect at all from extract type, or vice versa. Nevertheless, the extract type induced the most marked changes in bioactivity of laurel samples. From the PCA biplot, it became clear that wild samples were more effective to inhibit tumor cell lines growth, especially HeLa, MCF7, NCI-H460 and HCT15. It was also observed that methanolic extracts tended to have higher antimicrobial activity, except for Aspergillus niger, Aspergillus. fumigatus and Penicillium verrucosum. The differences in bioactivity might be related to the higher phenolic compounds content (flavonols, flavones and even, total phenolic compounds) presented by methanolic extracts,. The most interesting finding in this work was the bioactive specificity of each laurel extract, considering its wild or cultivated origin. Moreover, from the PCA biplot obtained is possible to choose the combination extract type/origin with potentially highest effect against determined bacteria, fungi or tumor cell line, depending on the objective of the study.FCT for financial support, CIMO (strategic project PEst-OE/AGR/UI0690/2011), REQIMTE (PEst-C/EQB/LA0006/2011), M.I. Dias (SFRH/BD/84485/2012), R.C. Calhelha (SFRH/BPD/68344/2010) and J.C.M. Barreira (BPD/72802/2010

    Absolute Configuration of a Tetrahydrophenanthrene from Heliotropium ovalifolium by LC-NMR of Its Mosher Esters

    Get PDF
    A new tetrahydrophenanthrene (1, (1R,2R)-1-hydroxy-2-methoxy-6,9-dimethyl-2,3-dihydrophenanthren-4(1H)-one (heliophenanthrone)) has been isolated from the aerial parts of Heliotropium ovalifolium. Its structure was elucidated on the basis of spectroscopic data, and the absolute configuration of the asymmetric centers was determined from LC-NMR data of the Mosher ester derivatives

    Same-sign dileptons as a signature for heavy Majorana neutrinos in hadron-hadron collisions

    Get PDF
    We discuss the possibility of same-sign dileptons as a signature for Majorana neutrinos. The production mechanism is given by a single heavy neutrino production and decay proton-proton -> l^{\pm} N X -> l^{\pm} l^{\pm} X'. Cross section and distributions are presented for the LHC energies.Comment: 07 pages, LaTeX; to be published in Physics Letters

    Universality of the Crossing Probability for the Potts Model for q=1,2,3,4

    Full text link
    The universality of the crossing probability πhs\pi_{hs} of a system to percolate only in the horizontal direction, was investigated numerically by using a cluster Monte-Carlo algorithm for the qq-state Potts model for q=2,3,4q=2,3,4 and for percolation q=1q=1. We check the percolation through Fortuin-Kasteleyn clusters near the critical point on the square lattice by using representation of the Potts model as the correlated site-bond percolation model. It was shown that probability of a system to percolate only in the horizontal direction πhs\pi_{hs} has universal form πhs=A(q)Q(z)\pi_{hs}=A(q) Q(z) for q=1,2,3,4q=1,2,3,4 as a function of the scaling variable z=[b(q)L1ν(q)(ppc(q,L))]ζ(q)z= [ b(q)L^{\frac{1}{\nu(q)}}(p-p_{c}(q,L)) ]^{\zeta(q)}. Here, p=1exp(β)p=1-\exp(-\beta) is the probability of a bond to be closed, A(q)A(q) is the nonuniversal crossing amplitude, b(q)b(q) is the nonuniversal metric factor, ζ(q)\zeta(q) is the nonuniversal scaling index, ν(q)\nu(q) is the correlation length index. The universal function Q(x)exp(z)Q(x) \simeq \exp(-z). Nonuniversal scaling factors were found numerically.Comment: 15 pages, 3 figures, revtex4b, (minor errors in text fixed, journal-ref added
    corecore