4,229 research outputs found

    Dynamical Complexity, Intermittent Turbulence, Coarse-Grained Dissipation, Criticality and Multifractal Processes

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    The ideas of dynamical complexity induced intermittent turbulence by sporadic localized interactions of coherent structures are discussed. In particular, we address the phenomenon of magnetic reconfiguration due to coarse-grained dissipation as well as the interwoven connection between criticality and multifractal processes. Specific examples are provided.Comment: 6 pages, 2 figures, submitted to AIP Conference Proceedings for the 6th Annual International Astrophysics Conference, Honolulu, March 16-22, 200

    Relativism and universalism in interrogation fairness: a comparative analysis between Europe and China

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    This paper addresses Chinese interrogation rules from historical and comparative perspectives by relating them to the very different development of interrogation procedure in Europe. A fuller understanding of the evolution of the rules in both contexts is relevant to the present day controversy concerning the universal versus relative nature of interrogation fairness. The comparative analysis reveals that, in fact, the influence of ancient Greek and Chinese civilizations resulted in a great difference between Europe and China regarding legal cultures and institutional arrangements for criminal interrogation procedure. Considering future legal reforms in China, and given the very different historical and institutional context, the likelihood seems low that an ‘autonomous version’ of the right to remain silent and the privilege against self-incrimination will develop on China’s very different soil. However, traditional native resources are also available to legal reformers to ensure a cooperative interviewing style in criminal questioning, and eliminate police-coerced confessions

    Pulsar timing in extreme mass ratio binaries: a general relativistic approach

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    The detection of a pulsar (PSR) in a tight, relativistic orbit around a supermassive or intermediate mass black hole - such as those in the Galactic centre or in the centre of Globular clusters - would allow for precision tests of general relativity (GR) in the strong-field, non-linear regime. We present a framework for calculating the theoretical time-frequency signal from a PSR in such an Extreme Mass Ratio Binary (EMRB). This framework is entirely relativistic with no weak-field approximations and so able to account for all higher-order strong-field gravitational effects, relativistic spin dynamics, the convolution with astrophysical effects and the combined impact on the PSR timing signal. Specifically we calculate both the spacetime path of the pulsar radio signal and the complex orbital and spin dynamics of a spinning pulsar around a Kerr black hole, accounting for spacetime curvature and frame dragging, relativistic and gravitational time delay, gravitational light bending, temporal and spatial dispersion induced by the presence of plasma along the line of sight and relativistic aberration. This then allows for a consistent time-frequency solution to be generated. Such a framework is key for assessing the use of PSR as probes of strong field GR, helping to inform the detection of an EMRB system hosting a PSR and, most essentially, for providing an accurate theoretical basis to then compare with observations to test fundamental physics.Comment: 19 pages, 15 Figures. Accepted for publication in MNRA

    Preferential Acceleration of Coherent Magnetic Structures and Bursty Bulk Flows in Earth's Magnetotail

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    Observations indicate that the magnetotail convection is turbulent and bi-modal, consisting of fast bursty bulk flows (BBF) and a nearly stagnant background. We demonstrate that this observed phenomenon may be understood in terms of the intermittent interactions, dynamic mergings and preferential accelerations of coherent magnetic structures under the influence of a background magnetic field geometry that is consistent with the development of an X-point mean-field structure.Comment: 12 pages, 5 Postscript figures, uses agums.st

    The Green500 List: Escapades to Exascale

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    Energy efficiency is now a top priority. The first four years of the Green500 have seen the importance of en- ergy efficiency in supercomputing grow from an afterthought to the forefront of innovation as we near a point where sys- tems will be forced to stop drawing more power. Even so, the landscape of efficiency in supercomputing continues to shift, with new trends emerging, and unexpected shifts in previous predictions. This paper offers an in-depth analysis of the new and shifting trends in the Green500. In addition, the analysis of- fers early indications of the track we are taking toward exas- cale, and what an exascale machine in 2018 is likely to look like. Lastly, we discuss the new efforts and collaborations toward designing and establishing better metrics, method- ologies and workloads for the measurement and analysis of energy-efficient supercomputing
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