663 research outputs found

    Modern seawater acidification: The response of foraminifera to high-CO<inf>2</inf> conditions in the Mediterranean Sea

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    The seas around the island of Ischia (Italy) have a lowered pH as a result of volcanic gas vents that emit carbon dioxide from the sea floor at ambient seawater temperatures. These areas of acidified seawater provide natural laboratories in which to study the long-term biological response to rising CO2 levels. Benthic foraminifera (single-celled protists) are particularly interesting as they have short life histories, are environmentally sensitive and have an excellent fossil record. Here, we examine changes in foraminiferal assemblages along pH gradients at CO2 vents on the coast of Ischia and show that the foraminiferal distribution, diversity and nature of the fauna change markedly in the living assemblages as pH decreases. © 2010 Geological Society of London

    Consumer-based brand equity and brand performance

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    The relation between consumer-based brand equity and brand performance was investigated across 15 product categories in Brazil and the UK. Brand equity was conceptualized as related to the level of social benefit offered by each brand and was measured with a simple questionnaire that asked consumers to rate brands with respect to their familiarity and quality levels. These measures were then related to brand market share and revenue. Results showed that the relation between consumer-based brand equity and brand performance varies across product categories, indicating that products differ with respect to their level of brandability and suggesting ways to measure it

    Percolation approach to quark gluon plasma in high energy pp collisions

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    We apply continuum percolation to proton-proton collisions and look for the possible threshold to phase transition from confined nuclear matter to quark gluon plasma. Making the assumption that J/Psi suppression is a good signal to the transition, we discuss this phenomenon for pp collisions, in the framework of a dual model with strings.Comment: 8 pages, 3 figure

    Creating low-cost soil maps for tropical agriculture using gaussian processes

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    Study on the use of Typha spp. for the phytotreatment of water contaminated with ibuprofen

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    Several studies on phytotoxic effects caused by organic xenobiotics and their removal from water by macrophytes have already been performed to evaluate the usefulness of these plants for phytoremediation technologies. In this context, a study was conducted to assess Typha spp.’s ability to withstand and remove, from water, the non-steroidal anti-inflammatory drug ibuprofen. For an initial ibuprofen concentration of 20 mgL 1, Typha removed nearly 60% of it within the first 24 h, attaining over 99% removal by the end of the assay (21 days). Exposure to higher ibuprofen concentrations did affect Typha’s growth but, by the end of the assays, plants’ growth as well as photosynthetic pigments approached normal values. An alteration in antioxidant enzymes activities (superoxide dismutase, catalase, guaiacol peroxidase) indicated that both roots and leaves were affected by the xenobiotic. Eventually, Typha seemed able to cope with ibuprofen’s induced oxidative damage suggesting its ability for phytotreatment of waters contaminated with ibuprofen

    Explaining the Higgs Decays at the LHC with an Extended Electroweak Model

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    We show that the recent discovery of a new boson at the LHC, which we assume to be a Higgs boson, and the observed enhancement in its diphoton decays compared to the SM prediction, can be explained by a new doublet of charged vector bosons from an extended electroweak gauge sector model with SU(3)_C\otimesSU(3)_L\otimesU(1)_X symmetry. Our results show a good agreement between our theoretical expected sensitivity to a 126--125 GeV Higgs boson and the experimental significance observed in the diphoton channel at the 8 TeV LHC. Effects of an invisible decay channel for the Higgs boson are also taken into account, in order to anticipate a possible confirmation of deficits in the branching ratios into ZZZZ^*, WWWW^*, bottom quarks, and tau leptons.Comment: 16 pages, 5 figure

    Two-body ZZ' decays in the minimal 331 model

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    The two-body decays of the extra neutral boson Z_2 predicted by the minimal 331 model are analyzed. At the three-level it can decay into standard model particles as well as exotic quarks and the new gauge bosons predicted by the model. The decays into a lepton pair are strongly suppressed, with Br(Z2>l+l) 102Br(Z_2 --> l^+l^-) ~ 10^{-2} and Br(Z2>νˉlν) 103Br(Z_2 --> \bar{\nu}_l \nu) ~ 10^{-3}. In the bosonic sector, Z_2 would decay mainly into a pair of bilepton gauge bosons, with a branching ratio below the 0.1 level. The Z_2 boson has thus a leptophobic and bileptophobic nature and it would decay dominantly into quark pairs. The anomaly-induced decays Z2>Z1γZ_2 --> Z_1\gamma and Z2>Z1Z1Z_2 --> Z_1Z_1, which occurs at the one-loop level are studied. It is found that Br(Z2>Z1γ) 109Br(Z_2 --> Z_1\gamma) ~ 10^{-9} and Br(Z2>Z1Z1) 106Br(Z_2 --> Z_1Z_1) ~ 10^{-6} at most. As for the Z2>W+WZ_2 --> W^+W^- and Z2>Z1HZ_2 --> Z_1H decays, with H a relatively light Higgs boson, they are induced via Z'-Z mixing. It is obtained that Br(Z2>W+W) 102Br(Z_2 --> W^+W^-) ~ 10^{-2} and Br(Z2>Z1H) 105Br (Z_2 --> Z_1H) ~ 10^{-5}. We also examine the flavor changing neutral current decays Z2>tcZ_2 --> tc and Z2>tuZ_2 --> tu, which may have branching fractions as large as 10310^{-3} and 10510^{-5}, respectively, and thus may be of phenomenological interest.Comment: 14 pages, 3 figures, submitted to Physical Review

    Effect Of Pasteurization On The Decay Of Mycobacterium Bovis In Milk Cream

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    Milk cream must be pasteurized in order to be sold in Brazil. However, there are no specific legal requirements for this product, and producers set their own pasteurization parameters using the ones approved for milk as a reference. Considering that fat protects bacteria from heat, that no thermal inactivation studies have been performed on Mycobacterium bovis present in cream, and that bovine tuberculosis is endemic in Brazil, the aim of this study was to evaluate the inactivation of M. bovis in milk cream subjected to commercial parameters of pasteurization. Milk cream samples were contaminated and pasteurized in a water bath at 75, 80, 85, and 90°C for 5 and 15 s. M. bovis cells were plated onto Stonebrink-Leslie medium, incubated at 36°C for 45 days, and quantified; the result was expressed in log CFU mL-1. The fat content of the samples ranged from 34% to 37% and the average initial load of M. bovis was 8.0 Log CFU mL-1. The average decay of the M. bovis populations was 4.0, 4.3, 4.9 and 6.7 log CFU mL-1 when the cream was treated for 15 sec at 75, 80, 85 and 90°C, respectively, showing that the efficiency of the heat treatment was improved by increasing the temperature of the process. Given the lipophilic nature of M. bovis, the cream should be subjected to more intense parameters of pasteurization than those applied to milk.3753737374
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