5,621 research outputs found

    An Enhanced Nonlinear Critical Gradient for Electron Turbulent Transport due to Reversed Magnetic Shear

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    The first nonlinear gyrokinetic simulations of electron internal transport barriers (e-ITBs) in the National Spherical Torus Experiment show that reversed magnetic shear can suppress thermal transport by increasing the nonlinear critical gradient for electron-temperature-gradient-driven turbulence to three times its linear critical value. An interesting feature of this turbulence is nonlinearly driven off-midplane radial streamers. This work reinforces the experimental observation that magnetic shear is likely an effective way of triggering and sustaining e-ITBs in magnetic fusion devices.Comment: 4 pages, 5 figure

    An Enhanced Nonlinear Critical Gradient for Electron Turbulent Transport due to Reversed Magnetic Shear

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    The first nonlinear gyrokinetic simulations of electron internal transport barriers (e-ITBs) in the National Spherical Torus Experiment show that reversed magnetic shear can suppress thermal transport by increasing the nonlinear critical gradient for electron-temperature-gradient-driven turbulence to three times its linear critical value. An interesting feature of this turbulence is nonlinearly driven off-midplane radial streamers. This work reinforces the experimental observation that magnetic shear is likely an effective way of triggering and sustaining e-ITBs in magnetic fusion devices.Comment: 4 pages, 5 figure

    A comparison of vertical drift‐envelopes to conventional drift‐bottles

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109919/1/lno19752010141.pd

    The Formal Dynamism of Categories: Stops vs. Fricatives, Primitivity vs. Simplicity

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    Minimalist Phonology (MP; Pöchtrager 2006) constructs its theory based on the phonological epistemological principle (Kaye 2001) and exposes the arbitrary nature of standard Government Phonology (sGP) and strict-CV (sCV), particularly with reference to their confusion of melody and structure. For Pöchtrager, these are crucially different, concluding that place of articulation is melodic (expressed with elements), while manner of articulation is structural. In this model, the heads (xN and xO) can license and incorporate the length of the other into their own interpretation, that is xN influences xO projections as well as its own and vice versa. This dynamism is an aspect of the whole framework and this paper in particular will show that stops and fricatives evidence a plasticity of category and that, although fricatives are simpler in structure, stops are the more primitive of the two. This will be achieved phonologically through simply unifying the environment of application of the licensing forces within Pöchtrager's otherwise sound onset structure. In doing so, we automatically make several predictions about language acquisition and typology and show how lenition in Qiang (Sino-Tibetan) can be more elegantly explained

    Light scattering and phase behavior of Lysozyme-PEG mixtures

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    Measurements of liquid-liquid phase transition temperatures (cloud points) of mixtures of a protein (lysozyme) and a polymer, poly(ethylene glycol) (PEG) show that the addition of low molecular weight PEG stabilizes the mixture whereas high molecular weight PEG was destabilizing. We demonstrate that this behavior is inconsistent with an entropic depletion interaction between lysozyme and PEG and suggest that an energetic attraction between lysozyme and PEG is responsible. In order to independently characterize the lysozyme/PEG interactions, light scattering experiments on the same mixtures were performed to measure second and third virial coefficients. These measurements indicate that PEG induces repulsion between lysozyme molecules, contrary to the depletion prediction. Furthermore, it is shown that third virial terms must be included in the mixture's free energy in order to qualitatively capture our cloud point and light scattering data. The light scattering results were consistent with the cloud point measurements and indicate that attractions do exist between lysozyme and PEG.Comment: 5 pages, 2 figures, 1 tabl

    Liquid-like behaviour of gold nanowire bridges

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    A combination of Focused Ion Beam (FIB) and Reactive Ion Etch (RIE) was used to fabricate free standing gold nanowire bridges with radii of 30 nm and below. These were subjected to point loading to failure at their mid-points using an Atomic Force Microscope (AFM), providing strength and deformation data. The results demonstrate a dimensionally dependent transition from conventional solid metallic properties to liquid-like behaviour including the unexpected reformation of a fractured bridge. The work reveals mechanical and materials properties of nanowires which could have significant impact on nanofabrication processes and nanotechnology devices such as Nano Electro Mechanical Systems (NEMS)

    Relationship between brachycephalic airway syndrome and gastrointestinal signs in three breeds of dog

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    Objectives: To assess the breed-specific prevalence of, and effects of corrective airway surgery on, gastrointestinal signs in French bulldogs, English bulldogs and pugs presenting with brachycephalic airway syndrome to a referral teaching hospital. Materials and Methods: In this retrospective study, ptyalism, regurgitation and vomiting were graded at presentation using a previously established scoring system. Staphylectomy and nares resection were performed on all dogs. Gastrointestinal signs were re-assessed via telephone follow-up at least 6 weeks after surgery. Results: Ninety-eight dogs were included: French bulldogs (n=43), English bulldogs (n=12) and pugs (n=43). Overall population prevalence of all gastrointestinal signs was 56%. Breed-specific prevalence for French bulldogs was 93%, English bulldogs 58% and pugs 16%. There was post-surgical clinical improvement in gastrointestinal signs for the whole study population, especially in French bulldogs. Clinical Significance: The prevalence of gastrointestinal signs in dogs presenting with brachycephalic airway syndrome and improvement in these clinical signs following corrective surgery may vary between breeds

    Projected shell model study of odd-odd f-p-g shell proton-rich nuclei

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    A systematic study of 2-quasiparticle bands of the proton-rich odd-odd nuclei in the mass A ~ 70-80 region is performed using the projected shell model approach. The study includes Br-, Rb-, and Y-isotopes with N = Z+2, and Z+4. We describe the energy spectra and electromagnetic transition strengths in terms of the configuration mixing of the angular-momentum projected multi-quasiparticle states. Signature splitting and signature inversion in the rotational bands are discussed and are shown to be well described. A preliminary study of the odd-odd N = Z nucleus, 74Rb using the concept of spontaneous symmetry breaking is also presented.Comment: 14 pages, 7 figures, final version accepted by Phys. Rev.
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