34,978 research outputs found

    The evolution of electron density and temperature distributions in the topside ionosphere during magnetic storms

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    The latitudinal distributions of electron density and temperature during geomagnetic storms in the mid-latitude topside ionosphere are observed to change in a manner than can be related to the evolution of ring current particle populations. The region of auroral precipitation is characterized by correlated increases in electron temperature and density. Equatorwards of this region, there is a broad belt of elevated electron temperatures and depressed electron densities which is usually much broader than any stable auroral red arc distinguishable from the ground, but which is nevertheless the same basic physical phenomenon. The changes of position of this belt can be related to prior bursts of geomagnetic activity and injection of ring current particles into the magnetosphere

    Beyond capitalism and liberal democracy: on the relevance of GDH Cole’s sociological critique and alternative

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    This article argues for a return to the social thought of the often ignored early 20th-century English thinker GDH Cole. The authors contend that Cole combined a sociological critique of capitalism and liberal democracy with a well-developed alternative in his work on guild socialism bearing particular relevance to advanced capitalist societies. Both of these, with their focus on the limitations on ‘free communal service’ in associations and the inability of capitalism to yield emancipation in either production or consumption, are relevant to social theorists looking to understand, critique and contribute to the subversion of neoliberalism. Therefore, the authors suggest that Cole’s associational sociology, and the invitation it provides to think of formations beyond capitalism and liberal democracy, is a timely and valuable resource which should be returned to

    Parity effect and single-electron injection for Josephson-junction chains deep in the insulating state

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    We have made a systematic investigation of charge transport in 1D chains of Josephson junctions where the characteristic Josephson energy is much less than the single-island Cooper-pair charging energy, EJECPE_\mathrm{J}\ll E_{CP}. Such chains are deep in the insulating state, where superconducting phase coherence across the chain is absent, and a voltage threshold for conduction is observed at the lowest temperatures. We find that Cooper-pair tunneling in such chains is completely suppressed. Instead, charge transport is dominated by tunneling of single electrons, which is very sensitive to the presence of BCS quasiparticles on the superconducting islands of the chain. Consequently we observe a strong parity effect, where the threshold voltage vanishes sharply at a characteristic parity temperature TT^*, which is significantly lower than the the critical temperature, TcT_c. A measurable and thermally-activated zero-bias conductance appears above TT^*, with an activation energy equal to the superconducting gap, confirming the role of thermally-excited quasiparticles. Conduction below TT^* and above the voltage threshold occurs via injection of single electrons/holes into the Cooper-pair insulator, forming a non-equilibrium steady state with a significantly enhanced effective temperature. Our results explicitly show that single-electron transport dominates deep in the insulating state of Josephson-junction arrays. This conduction process has mostly been ignored in previous studies of both superconducting junction arrays and granular superconducting films below the superconductor-insulator quantum phase transition.Comment: 8 pages, 6 figure

    Measurements of the top-quark-pair production cross section in the dilepton channel at LHC

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    Measurements of the total top-quark-pair production cross section at 7TeV are presented, using data collected at the LHC by the ATLAS and CMS experiments in 2011. The total cross section is measured in the dilepton decay channels of the t¯t pair into two opposite-sign charged leptons and additional jets. The results are compared with the theory predictions

    Operation of solar cell arrays in dilute streaming plasmas

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    Operation of solar cell arrays in dilute streaming plasma
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