11,920 research outputs found

    The plastic limit of clays

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    The plastic limit of soils was first described by Atterberg in 1911. The thread-rolling test was standardised at the US Public Roads Bureau in the 1920s and 1930s, and has subsequently become one of the standard tests of soil mechanics. This paper reviews the original definitions of plastic limit as proposed by Atterberg, and proposes that the brittle failure observed in the plastic limit test is caused by either air entry or cavitation in the clay. Critical state soil mechanics is used to show that the observed range of undrained shear strengths of soils at plastic limit is consistent with this hypothesis. The fallacy that strength at plastic limit is a constant is highlighted, and the implications for geotechnical practice are discussed. </jats:p

    Correspondence: British Thoracic Society guideline on pulmonary rehabilitation in adults: Does objectivity have a sliding scale?

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    This article is made available through the Brunel Open Access Publishing Fund. Copyright © 2014 BMJ Publishing Group Ltd & British Thoracic Society. This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 3.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is noncommercial. See: http://creativecommons.org/licenses/ by-nc/3.0/No abstract available (Letter

    Towards Laser Driven Hadron Cancer Radiotherapy: A Review of Progress

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    It has been known for about sixty years that proton and heavy ion therapy is a very powerful radiation procedure for treating tumours. It has an innate ability to irradiate tumours with greater doses and spatial selectivity compared with electron and photon therapy and hence is a tissue sparing procedure. For more than twenty years powerful lasers have generated high energy beams of protons and heavy ions and hence it has been frequently speculated that lasers could be used as an alternative to RF accelerators to produce the particle beams necessary for cancer therapy. The present paper reviews the progress made towards laser driven hadron cancer therapy and what has still to be accomplished to realise its inherent enormous potential.Comment: 40 pages, 24 figure

    The Sloan Lens ACS Survey. IX. Colors, Lensing and Stellar Masses of Early-type Galaxies

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    We present the current photometric dataset for the Sloan Lens ACS (SLACS) Survey, including HST photometry from ACS, WFPC2, and NICMOS. These data have enabled the confirmation of an additional 15 grade `A' (certain) lens systems, bringing the number of SLACS grade `A' lenses to 85; including 13 grade `B' (likely) systems, SLACS has identified nearly 100 lenses and lens candidates. Approximately 80% of the grade `A' systems have elliptical morphologies while ~10% show spiral structure; the remaining lenses have lenticular morphologies. Spectroscopic redshifts for the lens and source are available for every system, making SLACS the largest homogeneous dataset of galaxy-scale lenses to date. We have developed a novel Bayesian stellar population analysis code to determine robust stellar masses with accurate error estimates. We apply this code to deep, high-resolution HST imaging and determine stellar masses with typical statistical errors of 0.1 dex; we find that these stellar masses are unbiased compared to estimates obtained using SDSS photometry, provided that informative priors are used. The stellar masses range from 10^10.5 to 10^11.8 M_\odot and the typical stellar mass fraction within the Einstein radius is 0.4, assuming a Chabrier IMF. The ensemble properties of the SLACS lens galaxies, e.g. stellar masses and projected ellipticities, appear to be indistinguishable from other SDSS galaxies with similar stellar velocity dispersions. This further supports that SLACS lenses are representative of the overall population of massive early-type galaxies with M* >~ 10^11 M_\odot, and are therefore an ideal dataset to investigate the kpc-scale distribution of luminous and dark matter in galaxies out to z ~ 0.5.Comment: 20 pages, 18 figures, 5 tables, published in Ap

    Neural processes of proactive and reactive controls modulated by motor-skill experiences

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    This study investigated the experience of open and closed motor skills on modulating proactive and reactive control processes in task switching. Fifty-four participants who were open-skilled

    T cells and dendritic cells in glomerular disease: the new glomerulotubular feedback loop

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    A newly described glomerulotubular feedback loop may explain the relationship between glomerular damage, epitope spreading, tubulointerstitial nephritis, proteinuria as a progression factor, and the importance of the local milieu in kidney damage. It also opens the horizons for exciting innovative approaches to therapy of both acute and chronic kidney diseases

    Extension of the Receptance Technique to Accommodate Distributed Connections

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    The receptance techniques has been used most frequently to analyze the vibrational response of structures that may be idealized as a set of substructures connected at one or more discrete points. However, the receptance technique can also be used to analyze the response of structures connected along particular types of line junctions. In this paper, an extension of the the receptance technique is presented that makes use of a generalized Fourier series approach to allow the evaluation of both the free and forced response of systems comprising components connected through spatially distributed junctions. The present extension is shown to reduce to the previous line receptance definition in the appropriate limit. The general distributed receptance formulation is demonstrated here through application to two problems involving coupled rods. The results obtained using the distributed receptance technique were found to compare well with the matching analytical solutions

    Economists' perspectives on leadership

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    What is leadership to an economist? This article provides an overview of formal models of leadership in economics. After briefly reviewing the role of formal control rights and the delegation of authority, the article puts in perspective economic models that capture several key functional aspects of leadership. The article also outlines a conceptual framework that includes five key elements of leadership: vision, communication, execution, integrity, and empowering others

    Sequences of Willmore surfaces

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    In this paper we develop the theory of Willmore sequences for Willmore surfaces in the 4-sphere. We show that under appropriate conditions this sequence has to terminate. In this case the Willmore surface either is the twistor projection of a holomorphic curve into complex projective space or the inversion of a minimal surface with planar ends in 4-space. These results give a unified explanation of previous work on the characterization of Willmore spheres and Willmore tori with non-trivial normal bundles by various authors.Comment: 10 page
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