831 research outputs found

    Comparing Probabilistic Models for Melodic Sequences

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    Modelling the real world complexity of music is a challenge for machine learning. We address the task of modeling melodic sequences from the same music genre. We perform a comparative analysis of two probabilistic models; a Dirichlet Variable Length Markov Model (Dirichlet-VMM) and a Time Convolutional Restricted Boltzmann Machine (TC-RBM). We show that the TC-RBM learns descriptive music features, such as underlying chords and typical melody transitions and dynamics. We assess the models for future prediction and compare their performance to a VMM, which is the current state of the art in melody generation. We show that both models perform significantly better than the VMM, with the Dirichlet-VMM marginally outperforming the TC-RBM. Finally, we evaluate the short order statistics of the models, using the Kullback-Leibler divergence between test sequences and model samples, and show that our proposed methods match the statistics of the music genre significantly better than the VMM.Comment: in Proceedings of the ECML-PKDD 2011. Lecture Notes in Computer Science, vol. 6913, pp. 289-304. Springer (2011

    A Snapshot of Online Wildlife Trade : Australian e-commerce trade of native and non-native pets  

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    Funding This project was funded by the Centre for Invasive Species Solutions (Project PO1-I-001). Adam Toomes was additionally supported by the FJ Sandoz PhD Scholarship. Pablo GarcĂ­aDĂ­az was funded by NERC grants NE/S011641/1 (Newton LATAM programme) and 2022GCBCCONTAIN.Peer reviewedPublisher PD

    The kk-essence scalar field in the context of Supernova Ia Observations

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    A kk-essence scalar field model having (non canonical) Lagrangian of the form L=−V(ϕ)F(X)L=-V(\phi)F(X) where X=1/2gΌΜ∇Όϕ∇ΜϕX=1/2g^{\mu\nu}\nabla_{\mu}\phi\nabla_{\nu}\phi with constant V(ϕ)V(\phi) is shown to be consistent with luminosity distance-redshift data observed for type Ia Supernova. For constant V(ϕ)V(\phi), F(X)F(X) satisfies a scaling relation which is used to set up a differential equation involving the Hubble parameter HH, the scale factor aa and the kk-essence field ϕ\phi. HH and aa are extracted from SNe Ia data and using the differential equation the time dependence of the field ϕ\phi is found to be: ϕ(t)∌λ0+λ1t+λ2t2\phi(t) \sim \lambda_0 + \lambda_1 t + \lambda_2 t^2. The constants λi\lambda_i have been determined. The time dependence is similar to that of the quintessence scalar field (having canonical kinetic energy) responsible for homogeneous inflation. Furthermore, the scaling relation and the obtained time dependence of the field ϕ\phi is used to determine the XX-dependence of the function F(X)F(X).Comment: 8 pages, 5 figures, Late

    Proton propagation in nuclei studied in the (e,e’p) reaction

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    Proton propagation in nuclei was studied using the (e,e’p) reaction in the quasifree region. The coincidence (e,e’p) cross sections were measured at an electron angle of 50.4° and proton angles of 50.1°, 58.2°, 67.9°, and 72.9° for 12C, 27Al, 58Ni, and 181Ta targets at a beam energy of 779.5 MeV. The average outgoing proton energy was 180 MeV. The ratio of the (e,e’p) yield to the simultaneously measured (e,e’) yield was compared to that calculated in the plane-wave impulse approximation and an experimental transmission defined. These experimental transmissions are considerably larger (a factor of ∌2 for 181Ta) than those one would calculate from the free N-N cross sections folded into the nuclear density distribution. A new calculation that includes medium effects (N-N correlations, density dependence of the N-N cross sections and Pauli suppression) accounts for this increase

    The Weak Charge of the Proton and New Physics

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    We address the physics implications of a precision determination of the weak charge of the proton, QWP, from a parity violating elastic electron proton scattering experiment to be performed at the Jefferson Laboratory. We present the Standard Model (SM) expression for QWP including one-loop radiative corrections, and discuss in detail the theoretical uncertainties and missing higher order QCD corrections. Owing to a fortuitous cancellation, the value of QWP is suppressed in the SM, making it a unique place to look for physics beyond the SM. Examples include extra neutral gauge bosons, supersymmetry, and leptoquarks. We argue that a QWP measurement will provide an important complement to both high energy collider experiments and other low energy electroweak measurements. The anticipated experimental precision requires the knowledge of the order alpha_s corrections to the pure electroweak box contributions. We compute these contributions for QWP, as well as for the weak charges of heavy elements as determined from atomic parity violation.Comment: 22 pages of LaTeX, 5 figure

    The spiritual organization: critical reflections on the instrumentality of workplace spirituality

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    Authors' draft of article. Final version published by Routledge in Journal of Management, Spirituality and Religion available online at: http://www.tandf.co.uk/journals/titles/14766086.aspThis paper offers a theoretical contribution to the current debate on workplace spirituality by: (a) providing a selective critical review of scholarship, research and corporate practices which treat workplace spirituality in performative terms, that is, as a resource or means to be manipulated instrumentally and appropriated for economic ends; (b) extending Ezioni’s analysis of complex organizations and proposing a new category, the ‘spiritual organization’, and; (c) positing three alternative positions with respect to workplace spirituality that follow from the preceding critique. The spiritual organization can be taken to represent the development of a trajectory of social technologies that have sought, incrementally, to control the bodies, minds, emotions and souls of employees. Alternatively, it might be employed to conceptualize the way in which employees use the workplace as a site for pursuing their own spiritualities (a reverse instrumentalism). Finally, we consider the possible incommensurability of ‘work organization’ and ‘spirituality’ discourses

    Elected Mayors: Leading Locally?

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    The directly elected executive mayor was introduced to England a decade ago. Drawing inspiration from European and American experience, the elected mayor appealed to both New Labour and Conservative commentators in offering a solution to perceived problems of local leadership. There was a shared view that governance of local areas was failing and that elected mayors were the answer. The first local referendums were held in 2001. Most have continued to reject the idea of the elected mayor. During 2012, the coalition government initiated 10 further mayoral referendums in England's largest cities but only one, Bristol, opted for an elected mayor. Overall, there is no evidence of widespread public support, yet the prospect of more mayors - with enhanced powers - remains firmly on the policy agenda. Drawing from a decade of research, this paper considers reasons for the persistence of the mayoral experiment, the importance of local factors in the few areas where mayors hold office and the link to current policy debates. Using the authors' analytical leadership grid, this paper links the governmental, governance and allegiance roles of mayors to the problematic nature of local leadership. It then draws tentative conclusions about the strange case of the elected mayor in England

    Tensor polarization in elastic electron-deuteron scattering in the momentum transfer range 3.8≀Q≀4.6 fm-1

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    The tensor polarization of the recoil deuteron in elastic electron-deuteron scattering has been measured at the Bates Linear Accelerator Center at three values of four-momentum transfer Q=3.78, 4.22, and 4.62 fm-1, corresponding to incident electron energies of 653, 755, and 853 MeV. The scattered electrons and the recoil deuterons were detected in coincidence. The recoil deuterons were transported to a liquid hydrogen target to undergo a second scattering. The angular distribution of the d→-p scattering was measured using a polarimeter. The polarimeter was calibrated in an auxiliary experiment using a polarized deuteron beam at the Laboratoire National Saturne. A Monte Carlo procedure was used to generate interpolated calibration data because the energy spread in the deuteron energies in the Bates experiment spanned the range of deuteron energies in the calibration experiment. The extracted values of t20 are compared to predictions of different theoretical models of the electromagnetic form factors of the deuteron: nonrelativistic and relativistic nucleon-meson dynamics, Skyrme model, quark models, and perturbative quantum chromodynamics. Along with the world data the structure functions A(Q) and B(Q) are used to separate the charge monopole and charge quadrupole form factors of the deuteron. A node in the charge monopole form factor is observed at Q=4.39±0.16 fm-1

    Measurement of tensor polarization in elastic electron-deuteron scattering in the momentum-transfer range 3.8≀q≀4.6 fm-1

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    The tensor polarization t20 of the recoil deuteron in elastic e-d scattering has been measured for three values of four-momentum transfer, q=3.78, 4.22, and 4.62 fm-1. The data have been used to locate the first node in the charge monopole form factor of the deuteron at q=4.39±0.16 fm-1. The results for t20 are in reasonable agreement with expectations based on the nucleon-meson description of nuclear dynamic
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