160,936 research outputs found

    Magnets with stabilized conductors

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    Method fabricates stabilized composite conductor, for use in construction of magnets, using equal amounts of superconducting and metal materials, thus reducing weight, cost and size

    Active Gel Model of Amoeboid Cell Motility

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    We develop a model of amoeboid cell motility based on active gel theory. Modeling the motile apparatus of a eukaryotic cell as a confined layer of finite length of poroelastic active gel permeated by a solvent, we first show that, due to active stress and gel turnover, an initially static and homogeneous layer can undergo a contractile-type instability to a polarized moving state in which the rear is enriched in gel polymer. This agrees qualitatively with motile cells containing an actomyosin-rich uropod at their rear. We find that the gel layer settles into a steadily moving, inhomogeneous state at long times, sustained by a balance between contractility and filament turnover. In addition, our model predicts an optimal value of the gel-susbstrate adhesion leading to maximum layer speed, in agreement with cell motility assays. The model may be relevant to motility of cells translocating in complex, confining environments that can be mimicked experimentally by cell migration through microchannels.Comment: To appear in New Journal of Physic

    Teaching spoken discourse markers explicitly: A comparison of III and PPP

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    This article reports on mixed methods classroom research carried out at a British university. The study investigates the effectiveness of two different explicit teaching frameworks, Illustration, Interaction, Induction (III) and Present, Practice, Produce (PPP) used to teach the same spoken discourse markers (DMs) to two different groups of Chinese learners and compared to a control group. Univariate analysis of the pre and post tests indicated statistically significant differences between the PPP group and III/control groups in terms of a higher mean usage of the target DMs in the immediate post test. Qualitative results demonstrated that the PPP group generally found this method to be more useful, which tallied with their better performances in the tests. Both groups also articulated a desire for a different kind of practice to be used in class, based on rehearsal for real world tasks. This suggests a need to reconceptualise practice within III, PPP or other teaching frameworks

    The K Band Luminosity Functions of Galaxies in High Redshift Clusters

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    K band luminosity functions (LFs) of three, massive, high redshift clusters of galaxies are presented. The evolution of K*, the characteristic magnitude of the LF, is consistent with purely passive evolution, and a redshift of forma tion z = 1.5-2.Comment: 3 pages, to appear in Proceedings of IAU Colloquium 195 - Outskirts of Galaxy Clusters: intense life in the suburb
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