66 research outputs found

    Diet, nutrition, obesity and their role in arthritis

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    Obesity and poor nutrition, individually and together, have created costly musculoskeletal disease epidemic in the United States. Processed food, with abundant empty calories, has contributed greatly to our dietary woes. Much of the food consumed today is packed with calories but refined to the point that essential nutrients are lacking. Even worse, processed food may have ingredients added that are detrimental to good health. Abundant research has documented a close relationship between obesity, poor diet and orthopaedic problems. Dietary supplements have been proven to provide both disease prevention and therapeutic benefits. Unfortunately, many weight loss programs and methods are ineffective and possibly dangerous. Additionally, the FDA does not regulate the nutritional supplement industry and product quality is high variable. It is imperative that physicians treating patients with musculoskeletal complaints understand these disease producing relationships and have a network in place to refer patients to reputable weight loss entities and for high quality nutritional supplements

    Nonlinear lattice model of viscoelastic Mode III fracture

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    We study the effect of general nonlinear force laws in viscoelastic lattice models of fracture, focusing on the existence and stability of steady-state Mode III cracks. We show that the hysteretic behavior at small driving is very sensitive to the smoothness of the force law. At large driving, we find a Hopf bifurcation to a straight crack whose velocity is periodic in time. The frequency of the unstable bifurcating mode depends on the smoothness of the potential, but is very close to an exact period-doubling instability. Slightly above the onset of the instability, the system settles into a exactly period-doubled state, presumably connected to the aforementioned bifurcation structure. We explicitly solve for this new state and map out its velocity-driving relation

    Role of confined phonons in thin film superconductivity

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    We calculate the critical temperature TcT_c and the superconducting energy gaps Δn\Delta_n of a thin film superconductor system, where Δn\Delta_n is the superconducting energy gap of the nn-th subband. Since the quantization of both the electron energy and phonon spectrum arises due to dimensional confinement in one direction, the effective electron-electron interaction mediated by the quantized confined phonons is different from that mediated by the bulk phonon, leading to the modification of TcT_c in the thin film system. We investigate the dependence of TcT_c and Δn\Delta_n on the film thickness dd with this modified interaction.Comment: 4 pages, 2 figure

    Effects of crack tip geometry on dislocation emission and cleavage: A possible path to enhanced ductility

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    We present a systematic study of the effect of crack blunting on subsequent crack propagation and dislocation emission. We show that the stress intensity factor required to propagate the crack is increased as the crack is blunted by up to thirteen atomic layers, but only by a relatively modest amount for a crack with a sharp 60∘^\circ corner. The effect of the blunting is far less than would be expected from a smoothly blunted crack; the sharp corners preserve the stress concentration, reducing the effect of the blunting. However, for some material parameters blunting changes the preferred deformation mode from brittle cleavage to dislocation emission. In such materials, the absorption of preexisting dislocations by the crack tip can cause the crack tip to be locally arrested, causing a significant increase in the microscopic toughness of the crack tip. Continuum plasticity models have shown that even a moderate increase in the microscopic toughness can lead to an increase in the macroscopic fracture toughness of the material by several orders of magnitude. We thus propose an atomic-scale mechanism at the crack tip, that ultimately may lead to a high fracture toughness in some materials where a sharp crack would seem to be able to propagate in a brittle manner. Results for blunt cracks loaded in mode II are also presented.Comment: 12 pages, REVTeX using epsfig.sty. 13 PostScript figures. Final version to appear in Phys. Rev. B. Main changes: Discussion slightly shortened, one figure remove

    Resistance through realism : Youth subculture films in 1970s (and 1980s) Britain

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    This document is the Accepted Manuscript version of the following article: Nathaniel Weiner, ‘Resistance through realism: Youth subculture films in 1970s (and 1980s) Britain’. The final, definitive version of this paper has been published in European Journal of Cultural Studies, November 2015, DOI: https://doi.org/10.1177/1367549415603376. Published by SAGE Publishing.Film scholars have argued that the British social realist films of the late 1950s and early 1960s reflect the concerns articulated by British cultural studies during the same period. This article looks at how the social realist films of the 1970s and early 1980s similarly reflect the concerns of British cultural studies scholarship produced by the University of Birmingham’s Centre for Contemporary Cultural Studies during the 1970s. It argues that the Centre for Contemporary Cultural Studies’ approach to stylised working-class youth subcultures is echoed in the portrayal of youth subcultures in the social realist films Pressure (1976), Bloody Kids (1979), Babylon (1980) and Made in Britain (1982). This article explores the ways in which these films show us both the strengths and weaknesses of the Centre for Contemporary Cultural Studies’ work on subcultures.Peer reviewe
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