1,067 research outputs found

    Library Event Matching event classification algorithm for electron neutrino interactions in the NOvA detectors

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    We describe the Library Event Matching classification algorithm implemented for use in the NOvA νμνe\nu_\mu \rightarrow \nu_e oscillation measurement. Library Event Matching, developed in a different form by the earlier MINOS experiment, is a powerful approach in which input trial events are compared to a large library of simulated events to find those that best match the input event. A key feature of the algorithm is that the comparisons are based on all the information available in the event, as opposed to higher-level derived quantities. The final event classifier is formed by examining the details of the best-matched library events. We discuss the concept, definition, optimization, and broader applications of the algorithm as implemented here. Library Event Matching is well-suited to the monolithic, segmented detectors of NOvA and thus provides a powerful technique for event discrimination.Comment: 10 pages, 7 figures. Minor fixe

    Results from MINOS and NOνA

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    The MINOS experiment, operating in the NuMI beam since 2005, has provided the most precise measurement of the atmospheric mass splitting |Δm^2_(32)|, and the recent combination of the ν_μ, ν_e, and atmospheric neutrino samples has provided some evidence of non-maximal mixing, and hints about the neutrino mass hierarchy and the Φ_(23) octant. Construction of the NOνA experiment, situated off-axis in the upgraded NuMI beam, is almost complete. Over the coming years it will have significant power to probe the questions of the mass hierarchy, Φ _(23) octant, and the possibility of CP violation in the lepton sector. This paper gives an overview of the results from MINOS, and of the sensitivity of the NOνA experiment

    A data summary file structure and analysis tools for neutrino oscillation analysis at the NOνA experiment

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    The NuMI Off-axis Neutrino Experiment (NOvA) is designed to study neutrino oscillations in the NuMI beam at Fermilab. Neutrinos at the Main Injector (NuMI) is currently being upgraded to provide 700 kW for NOvA. A 14 kt Far Detector in Ash River, MN and a functionally identical 0.3 kt Near Detector at Fermilab are positioned 810 km apart in the NuMI beam line. The fine granularity of the NOvA detectors provides a detailed representation of particle trajectories. The data volume associated with such granularity, however, poses problems for analyzing data with ease and speed. NOvA has developed a data summary file structure which discards the full event record in favor of higher-level reconstructed information. A general- purpose framework for neutrino oscillation measurements has been developed for analysis of these data summary files. We present the design methodology for this new file format as well as the analysis framework and the role it plays in producing NOvA physics results

    Calculating path algorithms

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    AbstractA calculational derivation is given of two abstract path algorithms. The first is an all-pairs algorithm, two well-known instances of which are Warshall's (reachability) algorithm and Floyd's shortest-path algorithm; instances of the second are Dijkstra's shortest-path algorithm and breadth-first/depth-first search of a directed graph. The basis for the derivations is the algebra of regular languages

    Study on Doping Prevention: A map of Legal, Regulatory and Prevention Practice Provisions in EU 28

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    Historically, anti-doping efforts have focused on the detection and deterrence of doping in elite and competitive sport. There is, however, a growing concern that doping is occurring outside the organised sporting system; giving rise to the belief that the misuse of doping agents in recreational sport has become a societal problem and a public health issue that must be addressed. The EU Commission awarded a contract (EAC/2013/0617) to a Consortium to undertake this Study with the aim of developing the evidence-base for policies designed to combat doping in recreational sport. Fourteen internationally recognised experts shaped the Study which comprised (i) the collection of primary data through a structured survey, and (ii) secondary data through literature searches and website analysis. All 28 Member States participated in the information-gathering process. Specifically, this involved a systematic study of the ethical considerations, legal position, prevention research landscape, and current practise in relation to the prevention of doping in recreational sport. The Study provides a comprehensive overview of current practice and legislation as it applies to the prevention of doping and promotes and supports the sharing of best practices in the EU regarding the fight against doping in recreational sport. It concludes with seven recommendations for future action that focus on the need for a coordinated response in relation to the problems arising from doping in recreational sport

    A 'moment-conserving' reformulation of GW theory

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    We show how to construct an effective Hamiltonian whose dimension scales linearly with system size, and whose eigenvalues systematically approximate the excitation energies of GWGW theory. This is achieved by rigorously expanding the self-energy in order to exactly conserve a desired number of frequency-independent moments of the self-energy dynamics. Recasting GWGW in this way admits a low-scaling O[N4]\mathcal{O}[N^4] approach to build this Hamiltonian, with a proposal to reduce this further to O[N3]\mathcal{O}[N^3]. This relies on exposing a novel recursive framework for the density response moments of the random phase approximation (RPA), where the efficient calculation of its starting point mirrors the low-scaling approaches to compute RPA correlation energies. The frequency integration of GWGW which distinguishes so many different GWGW variants can be performed directly and cheaply in this moment representation. Furthermore, the solution to the Dyson equation can be performed exactly, avoiding analytic continuation, diagonal approximations or iterative solutions to the quasiparticle equation, with the full-frequency spectrum of all solutions obtained in a complete diagonalization of this effective static Hamiltonian. We show how this approach converges rapidly with respect to the order of the conserved self-energy moments, and is applied across the GW100GW100 benchmark dataset to obtain accurate GWGW spectra in comparison to traditional implementations. We also show the ability to systematically converge all-electron full-frequency spectra and high-energy features beyond frontier excitations, as well as avoiding discontinuities in the spectrum which afflict many other GWGW approaches

    Yallalie: a Buried Structure of Possible Impact Origin in the Perth Basin, Western Australia

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    An enigmatic buried structure, located in Mesozoic sedimentary rocks in the Perth Basin, Western Australia, was discovered in 1990 by Ampol Exploration. The basin-like Yallalie structure (centred on 30 26' 40.3'' S, 115 46' 16.4'' E) is circular in plan view and about 12 km in diameter. High resolution,seismic-reflection profiles across the structure show a basin-shaped area of chaotic reflections that extend to a depth of approximately 2 km below the surface. The structure has sharp boundaries with surrounding faulted, but otherwise relatively undisturbed, rocks. In the centre of the structure there is an uplifted area approximately 3?4 km across, similar to those described from complex meteorite impact structures. The seismically defined structure coincides with a circular topographic depression, and image processing of digital elevation data has allowed recognition of concentric and radial structures extending as far as 40 km from the centre of the depression. Gravity surveys show the structure to be associated with a positive gravity anomaly of about 30 gu. Aeromagnetic surveys have defined annular anomalies associated with the central uplifted section, and possibly margins, of the structure. A search for siderophile element enrichments (by neutron activation analysis) in the rocks of the structure, which would indicate the presence of a meteorite component, proved negative. Quartz grains in cores that penetrate the structure show the development of prismatic cleavage fractures and irregular, slightly curved planes formed by brittle fracture. An allochthonous breccia of Late Cretaceous rocks occurs a few kilometres west of the western margin of the structure. Quartz grains from a thin veneer of Tertiary sediments that drape the structure are essentially undeformed. However, multiple sets of closely spaced planar deformation features in quartz, characteristic of highly shocked rocks, have yet to be observed in the rocks of the Yallalie structure and the allochthonous breccia. The morphology of the Yallalie structure determined from topographic and geophysical data suggests strongly that it is of impact origin. Geological and geochemical evidence is equivocal, but is not inconsistent with this interpretation

    Capturing accelerometer outputs in healthy volunteers under normal and simulated-pathological conditions using ML classifiers

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    Wearable devices offer a possible solution for acquiring objective measurements of physical activity. Most current algorithms are derived using data from healthy volunteers. It is unclear whether such algorithms are suitable in specific clinical scenarios, such as when an individual has altered gait. We hypothesized that algorithms trained on healthy population will result in less accurate results when tested in individuals with altered gait. We further hypothesized that algorithms trained on simulated-pathological gait would prove better at classifying abnormal activity.We studied healthy volunteers to assess whether activity classification accuracy differed for those with healthy and simulated-pathological conditions. Healthy participants (n=30) were recruited from the University of Leeds to perform nine predefined activities under healthy and simulated-pathological conditions. Activities were captured using a wrist-worn MOX accelerometer (Maastricht Instruments, NL). Data were analyzed based on the Activity-Recognition-Chain process. We trained a Neural-Network, Random-Forests, k-Nearest-Neighbors (k-NN), Support-Vector-Machines (SVM) and Naive Bayes models to classify activity. Algorithms were trained four times; once with 'healthy' data, and once with 'simulated-pathological data' for each of activity-type and activity-task classification. In activity-type instances, the SVM provided the best results; the accuracy was 98.4% when the algorithm was trained and then tested with unseen data from the same group of healthy individuals. Accuracy dropped to 52.8% when tested on simulated-pathological data. When the model was retrained with simulated-pathological data, prediction accuracy for the corresponding test set was 96.7%. Algorithms developed on healthy data are less accurate for pathological conditions. When evaluating pathological conditions, classifier algorithms developed using data from a target sub-population can restore accuracy to above 95%.Clinical Relevance - This method remotely establishes health-related data of objective outcome measures of activities of daily living

    X-ray Fluorescence Analysis of Feldspars and Silicate Glass: Effects of Melting Time on Fused Bead Consistency and Volatilisation

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    Reproducible preparation of lithium tetraborate fused beads for XRF analysis of glass and mineral samples is of paramount importance for analytical repeatability. However, as with all glass melting processes, losses due to volatilisation must be taken into account and their effects are not negligible. Here the effects of fused bead melting time have been studied for four Certified Reference Materials (CRM’s: three feldspars, one silicate glass), in terms of their effects on analytical variability and volatilisation losses arising from fused bead preparation. At melting temperatures of 1065 °C, and for feldspar samples, fused bead melting times shorter than approximately 25 min generally gave rise to a greater deviation of the XRF-analysed composition from the certified composition. This variation might be due to incomplete fusion and/or fused bead inhomogeneity but further research is needed. In contrast, the shortest fused bead melting time for the silicate glass CRM gave an XRF-analysed composition closer to the certified values than longer melting times. This may suggest a faster rate of glass-in-glass dissolution and homogenization during fused bead preparation. For all samples, longer melting times gave rise to greater volatilisation losses (including sulphates and halides) during fusion. This was demonstrated by a linear relationship between SO3 mass loss and time1/2, as predicted by a simple diffusion-based model. Iodine volatilisation displays a more complex relationship, suggestive of diffusion plus additional mechanisms. This conclusion may have implications for vitrification of iodine-bearing radioactive wastes. Our research demonstrates that the nature of the sample material impacts on the most appropriate fusion times. For feldspars no less than ~25 min and no more than ~60 min of fusion at 1065 °C, using Li2B4O7 as the fusion medium and in the context of feldspar samples and the automatic fusion equipment used here, strikes an acceptable (albeit non-ideal) balance between the competing factors of fused bead quality, analytical consistency and mitigating volatilisation losses. Conversely, for the silicate glass sample, shorter fusion times of less than ~30 min under the same conditions provided more accurate analyses whilst limiting volatile losses
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