3,446 research outputs found

    Extraction, quantification and degree of polymerization of yacon (Smallanthus sonchifolia) fructans

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    Yacon tubers have been a distinguished alternative of fructans, drawing the attention of researchers and food industries. Since fructans are carbohydrate reserves storage can reduce their contents. Additionally, the type of extraction used can provide a higher yield of fructans. Therefore, it was necessary to study yacon storage and its influence on the extraction and quantification of fructans. Thus, the objective of this study was to evaluate three fructan extractions (water 75°C, water 95°C, ethanol 90°C) in yacon with 3 sizes (large, medium, small), stored for 20 days, at room temperature as well as to compare two quantification techniques. The three extractions can be used when fructans are quantified by high performance liquid chromatography (HPLC). For quantification by spectrometry, the best extraction method was ethanol at 90°C. Medium and small-sized tubers presented the highest contents of fructans that large tubers, and storage negatively influenced these contents. Fructan quantification by HPLC was higher than the spectrophotometric technique. All treatments showed a degree of polymerization in the range from 3 to 7, allowing numerous technological applications for fructans present in yacon.Key words: Fructooligosaccharides, storage, tuber size

    Noncommutative Particles in Curved Spaces

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    We present a formulation in a curved background of noncommutative mechanics, where the object of noncommutativity ΞΌΜ\theta^{\mu\nu} is considered as an independent quantity having a canonical conjugate momentum. We introduced a noncommutative first-order action in D=10 curved spacetime and the covariant equations of motions were computed. This model, invariant under diffeomorphism, generalizes recent relativistic results.Comment: 1+15 pages. Latex. New comments and results adde

    Search for dark matter in association with a Higgs boson decaying to b-quarks in pp collisions at s=13 TeV with the ATLAS detector

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    A search for dark matter pair production in association with a Higgs boson decaying to a pair of bottom quarks is presented, using 3.2 fb−1 of pp collisions at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the LHC. The decay of the Higgs boson is reconstructed as a high-momentum bbÂŻ system with either a pair of small-radius jets, or a single large-radius jet with substructure. The observed data are found to be consistent with the expected backgrounds. Results are interpreted using a simplified model with a Zâ€Č gauge boson mediating the interaction between dark matter and the Standard Model as well as a two-Higgs-doublet model containing an additional Zâ€Č boson which decays to a Standard Model Higgs boson and a new pseudoscalar Higgs boson, the latter decaying into a pair of dark matter particles

    Search for resonances in the mass distribution of jet pairs with one or two jets identified as b-jets in proton–proton collisions at s=13 TeV with the ATLAS detector

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    © 2016 The AuthorSearches for high-mass resonances in the dijet invariant mass spectrum with one or two jets identified as b-jets are performed using an integrated luminosity of 3.2 fb−1 of proton–proton collisions with a centre-of-mass energy of s=13 TeV recorded by the ATLAS detector at the Large Hadron Collider. No evidence of anomalous phenomena is observed in the data, which are used to exclude, at 95% credibility level, excited b⁎ quarks with masses from 1.1 TeV to 2.1 TeV and leptophobic Zâ€Č bosons with masses from 1.1 TeV to 1.5 TeV. Contributions of a Gaussian signal shape with effective cross sections ranging from approximately 0.4 to 0.001 pb are also excluded in the mass range 1.5–5.0 TeV

    Classical and semi-classical energy conditions

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    The standard energy conditions of classical general relativity are (mostly) linear in the stress-energy tensor, and have clear physical interpretations in terms of geodesic focussing, but suffer the significant drawback that they are often violated by semi-classical quantum effects. In contrast, it is possible to develop non-standard energy conditions that are intrinsically non-linear in the stress-energy tensor, and which exhibit much better well-controlled behaviour when semi-classical quantum effects are introduced, at the cost of a less direct applicability to geodesic focussing. In this article we will first review the standard energy conditions and their various limitations. (Including the connection to the Hawking--Ellis type I, II, III, and IV classification of stress-energy tensors). We shall then turn to the averaged, nonlinear, and semi-classical energy conditions, and see how much can be done once semi-classical quantum effects are included.Comment: V1: 25 pages. Draft chapter, on which the related chapter of the book "Wormholes, Warp Drives and Energy Conditions" (to be published by Springer), will be based. V2: typos fixed. V3: small typo fixe

    Search for flavour-changing neutral currents in processes with one top quark and a photon using 81 fb−1 of pp collisions at s=13TeV with the ATLAS experiment

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    A search for flavour-changing neutral current (FCNC) events via the coupling of a top quark, a photon, and an up or charm quark is presented using 81 fb−1 of proton–proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Events with a photon, an electron or muon, a b-tagged jet, and missing transverse momentum are selected. A neural network based on kinematic variables differentiates between events from signal and background processes. The data are consistent with the background-only hypothesis, and limits are set on the strength of the tqγ coupling in an effective field theory. These are also interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tuγ coupling of 36 fb (78 fb) and on the branching ratio for t→γu of 2.8×10−5 (6.1×10−5). In addition, they are interpreted as 95% CL upper limits on the cross section for FCNC tγ production via a left-handed (right-handed) tcγ coupling of 40 fb (33 fb) and on the branching ratio for t→γc of 22×10−5 (18×10−5)
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