236 research outputs found

    Assessing the Economical and Environmental Impact of Cultivating Genetically Modified (GM) crops in Ireland

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    End of Project ReportAt present, there is no GM crop cultivation in Ireland. This could change in the near future however, following the inclusion of several GM maize varieties on the EU Common Seed Catalogue in 2004. Before an Irish GM tillage sector develops, information must be provided to farmers/regulators in regard to the potential economic impact of the technology and the environmental issues associated with GM crops. This project (RMIS 5211) has examined: 1. The economic cost-benefit of cultivating several GM crops (Phytophthora resistant potato, Septoria resistant wheat, Rhynchosporium resistant barley, Fusarium resistant wheat and herbicide tolerant sugar beet) 2. The environmental issue of gene flow by modelling the propensity of seven crop species (wheat, barley, sugar beet, oilseed rape, maize, potato and ryegrass) to spread their genetic material (be it GM/non-GM) through pollen/seed-mediated gene flow. The cost-benefit analysis specifically examined the impact of reduced chemical input and indicated that each GM crop tested would be more cost efficient than their conventional equivalent. Inputting the regimes and subsequent costs for the 2002 and 2003 growing season into the analysis, farmers would have returned a greater cost savings in 2002 for each of the GM crops, with the exception of potato. While a significant increase in gross margin was recorded for all GM crops, the greatest savings (€ha-1) occurred in the case of herbicide tolerant sugar beet in the absence (9.8% saving) or presence (23.2% saving) of a yield effect. Modelling a crop’s propensity to spread its genetic material (‘gene flow’) was achieved through the creation of a composite gene flow index (GFI) model. Taking into account both pollen and seed mediated data, presence/absence of interfertile wild relatives and current farming practises, a GFI value was returned for each crop. Unless the GM event altered the seed/pollen production of the crop, it can be anticipated that the same GFI value will apply to a GM/non-GM variety of the particular crop. Crops that returned the highest GFI values were ryegrass, oilseed rape and sugar beet. Importantly, a high GFI score does not imply the prohibition of GM varieties of that crop. Rather, it highlights those crops that possess a higher propensity for gene flow and thus require greater management precautions in light of coexistence regulations. To facilitate the provision of this and other relevant research information, a website (www.gmoinfo.ie) has been provided to further public understanding of the issues. Structured in a non-scientific format, this resource will be updated on a regular basis in response to public requests for further information and with research findings from the risk assessment programme at Oak park

    Portable instrument for in-vivo infrared oxymetry using spread-spectrum modulation

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    Near Infrared Spectroscopy (NIRS) can be employed to monitor noninvasively and continuously local changes in hemodynamics and oxygenation of human tissues. A portable NIRS research-grade acquisition system, dedicated to measurements during muscular exercise, is presented. The instrument is able to control up to eight LED sources and two detectors. A digital correlation technique, implemented on a single-chip RISC microcontroller, performs source-to-detector multiplexing. Such algorithm is highly optimized for computational efficiency and ambient noise rejection. Software-configurable input stages allow for flexibility in instrument setup. As a result of the specific correlation technique employed, the instrument is compact, lightweight and efficient. Clinical tests on oxygen consumption show excellent performance

    Portable instrument for in-vivo infrared oxymetry using spread-spectrum modulation

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    Near Infrared Spectroscopy (NIRS) can be employed to monitor noninvasively and continuously local changes in hemodynamics and oxygenation of human tissues. A portable NIRS research-grade acquisition system, dedicated to measurements during muscular exercise, is presented. The instrument is able to control up to eight LED sources and two detectors. A digital correlation technique, implemented on a single-chip RISC microcontroller, performs source-to-detector multiplexing. Such algorithm is highly optimized for computational efficiency and ambient noise rejection. Software-configurable input stages allow for flexibility in instrument setup. As a result of the specific correlation technique employed, the instrument is compact, lightweight and efficient. Clinical tests on oxygen consumption show excellent performance

    Social determinants of content selection in the age of (mis)information

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    Despite the enthusiastic rhetoric about the so called \emph{collective intelligence}, conspiracy theories -- e.g. global warming induced by chemtrails or the link between vaccines and autism -- find on the Web a natural medium for their dissemination. Users preferentially consume information according to their system of beliefs and the strife within users of opposite narratives may result in heated debates. In this work we provide a genuine example of information consumption from a sample of 1.2 million of Facebook Italian users. We show by means of a thorough quantitative analysis that information supporting different worldviews -- i.e. scientific and conspiracist news -- are consumed in a comparable way by their respective users. Moreover, we measure the effect of the exposure to 4709 evidently false information (satirical version of conspiracy theses) and to 4502 debunking memes (information aiming at contrasting unsubstantiated rumors) of the most polarized users of conspiracy claims. We find that either contrasting or teasing consumers of conspiracy narratives increases their probability to interact again with unsubstantiated rumors.Comment: misinformation, collective narratives, crowd dynamics, information spreadin

    MadGraph/MadEvent v4: The New Web Generation

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    We present the latest developments of the MadGraph/MadEvent Monte Carlo event generator and several applications to hadron collider physics. In the current version events at the parton, hadron and detector level can be generated directly from a web interface, for arbitrary processes in the Standard Model and in several physics scenarios beyond it (HEFT, MSSM, 2HDM). The most important additions are: a new framework for implementing user-defined new physics models; a standalone running mode for creating and testing matrix elements; generation of events corresponding to different processes, such as signal(s) and backgrounds, in the same run; two platforms for data analysis, where events are accessible at the parton, hadron and detector level; and the generation of inclusive multi-jet samples by combining parton-level events with parton showers. To illustrate the new capabilities of the package some applications to hadron collider physics are presented: 1) Higgs search in pp \to H \to W^+W^-: signal and backgrounds. 2) Higgs CP properties: pp \to H jj$in the HEFT. 3) Spin of a new resonance from lepton angular distributions. 4) Single-top and Higgs associated production in a generic 2HDM. 5) Comparison of strong SUSY pair production at the SPS points. 6) Inclusive W+jets matched samples: comparison with the Tevatron data.Comment: 38 pages, 15 figure

    Exploring nu signals in dark matter detectors

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    We investigate standard and non-standard solar neutrino signals in direct dark matter detection experiments. It is well known that even without new physics, scattering of solar neutrinos on nuclei or electrons is an irreducible background for direct dark matter searches, once these experiments each the ton scale. Here, we entertain the possibility that neutrino interactions are enhanced by new physics, such as new light force carriers (for instance a "dark photon") or neutrino magnetic moments. We consider models with only the three standard neutrino flavors, as well as scenarios with extra sterile neutrinos. We find that low-energy neutrino--electron and neutrino--nucleus scattering rates can be enhanced by several orders of magnitude, potentially enough to explain the event excesses observed in CoGeNT and CRESST. We also investigate temporal modulation in these neutrino signals, which can arise from geometric effects, oscillation physics, non-standard neutrino energy loss, and direction-dependent detection efficiencies. We emphasize that, in addition to providing potential explanations for existing signals, models featuring new physics in the neutrino sector can also be very relevant to future dark matter searches, where, on the one hand, they can be probed and constrained, but on the other hand, their signatures could also be confused with dark matter signals.Comment: 38 pages, 8 figures, 1 table; v3: eq 3 and nuclear recoil plots corrected, footnote added, conclusions unchange

    Measurements of the Production, Decay and Properties of the Top Quark: A Review

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    With the full Tevatron Run II and early LHC data samples, the opportunity for furthering our understanding of the properties of the top quark has never been more promising. Although the current knowledge of the top quark comes largely from Tevatron measurements, the experiments at the LHC are poised to probe top-quark production and decay in unprecedented regimes. Although no current top quark measurements conclusively contradict predictions from the standard model, the precision of most measurements remains statistically limited. Additionally, some measurements, most notably the forward-backward asymmetry in top quark pair production, show tantalizing hints of beyond-the-Standard-Model dynamics. The top quark sample is growing rapidly at the LHC, with initial results now public. This review examines the current status of top quark measurements in the particular light of searching for evidence of new physics, either through direct searches for beyond the standard model phenomena or indirectly via precise measurements of standard model top quark properties

    Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

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    We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

    Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

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    The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter
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