4,772 research outputs found

    Slip statistics of dislocation avalanches under different loading modes

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    Slowly compressed microcrystals deform via intermittent slip events, observed as displacement jumps or stress drops. Experiments often use one of two loading modes: an increasing applied stress (stress driven, soft), or a constant strain rate (strain driven, hard). In this work we experimentally test the influence of the deformation loading conditions on the scaling behavior of slip events. It is found that these common deformation modes strongly affect time series properties, but not the scaling behavior of the slip statistics when analyzed with a mean-field model. With increasing plastic strain, the slip events are found to be smaller and more frequent when strain driven, and the slip-size distributions obtained for both drives collapse onto the same scaling function with the same exponents. The experimental results agree with the predictions of the used mean-field model, linking the slip behavior under different loading modes

    Identification And Characterization Of A Second Encephalitogenic Determinant Of Myelin Proteolipid Protein (Residues 178-191) For SJL Mice

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    We previously described a synthetic peptide of myelin proteolipid protein (PLP), peptide 139-151, which induces experimental allergic encephalomyelitis in SJL/J (H-2s) mice. We have now identified an additional determinant, PLP residues 178-191, that is also a potent encephalitogen in this strain. When PLP peptide 178-191 was compared with peptide 139-151 on an equimolar basis, the day of onset of disease induced by PLP 178-191 was earlier, but the incidence, severity, and histologic features were indistinguishable. Lymph node cells from animals immunized with the whole PLP molecule responded to both PLP 178-191 and 139-151, suggesting immunologic codominance of the two epitopes. PLP 178-191 elicited stronger proliferative responses and this may relate to the earlier onset of disease induced with this peptide. Two CD4+, peptide-specific, I-A(s)-restricted T cell lines, selected by stimulation of lymph node cells with either PLP 178-191 or 139-151, were each encephalitogenic in naive syngeneic mice. The presence of multiple encephalitogenic codominant PLP epitopes within a single mouse strain emphasizes the complexity of the immune response to PLP and its potential as a target Ag in autoimmune demyelinating diseases

    Policy instruments in the Common Agricultural Policy

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    Policy changes in the Common Agricultural Policy (CAP) can be explained in terms of the exhaustion and long-term contradictions of policy instruments. Changes in policy instruments have reoriented the policy without any change in formal Treaty goals. The social and economic efficacy of instruments in terms of evidence-based policy analysis was a key factor in whether they were delegitimized. The original policy instruments were generally dysfunctional, but reframing the policy in terms of a multifunctionality paradigm permitted the development of more efficacious instruments. A dynamic interaction takes place between the instruments and policy informed by the predominant discourses

    The functional analysis of nonsense suppressors derived from in vitro engineered \u3ci\u3eSaccharomyces cerevisiae\u3c/i\u3e tRNA\u3csup\u3eTrp\u3c/sup\u3e genes

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    Nonsense suppressors derived from Saccharomyces cerevisiae tRNATrp genes have not been identified by classical genetic screens, although one can construct efficient amber (am) suppressors from them by making the appropriate anticodon mutation in vitro. Herein, a series of in vitro constructed putative suppressor genes was produced to test if pre-tRNATrp processing difficulties could help to explain the lack of classical tRNATrp-based suppressors. It is clear that inefficient processing of in-trons from precursor tRNATrp, or inaccurate overall processing, may explain why some of these constructs fail to promote nonsense suppression in vivo. However, deficient processing must be only one of the reasons why classical tRNATrp-based suppressors have not been characterized, as suppres-sion may still be extremely weak or absent in instances where the in vitro construct can lead to an accumulation of mature tRNATrp. Furthermore, suppression is also very weak in strains transformed with an intronless derivative of a putative tRNATrp ochre (oc) suppressor gene, wherein intron removal cannot pose a problem

    The functional analysis of nonsense suppressors derived from in vitro engineered \u3ci\u3eSaccharomyces cerevisiae\u3c/i\u3e tRNA\u3csup\u3eTrp\u3c/sup\u3e genes

    Get PDF
    Nonsense suppressors derived from Saccharomyces cerevisiae tRNATrp genes have not been identified by classical genetic screens, although one can construct efficient amber (am) suppressors from them by making the appropriate anticodon mutation in vitro. Herein, a series of in vitro constructed putative suppressor genes was produced to test if pre-tRNATrp processing difficulties could help to explain the lack of classical tRNATrp-based suppressors. It is clear that inefficient processing of in-trons from precursor tRNATrp, or inaccurate overall processing, may explain why some of these constructs fail to promote nonsense suppression in vivo. However, deficient processing must be only one of the reasons why classical tRNATrp-based suppressors have not been characterized, as suppres-sion may still be extremely weak or absent in instances where the in vitro construct can lead to an accumulation of mature tRNATrp. Furthermore, suppression is also very weak in strains transformed with an intronless derivative of a putative tRNATrp ochre (oc) suppressor gene, wherein intron removal cannot pose a problem

    A Multi-Wavelength Mass Analysis of RCS2 J232727.6-020437, a ~3x1015^{15}M⊙_{\odot} Galaxy Cluster at z=0.7

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    We present an initial study of the mass and evolutionary state of a massive and distant cluster, RCS2 J232727.6-020437. This cluster, at z=0.6986, is the richest cluster discovered in the RCS2 project. The mass measurements presented in this paper are derived from all possible mass proxies: X-ray measurements, weak-lensing shear, strong lensing, Sunyaev Zel'dovich effect decrement, the velocity distribution of cluster member galaxies, and galaxy richness. While each of these observables probe the mass of the cluster at a different radius, they all indicate that RCS2 J232727.6-020437 is among the most massive clusters at this redshift, with an estimated mass of M_200 ~3 x10^15 h^-1 Msun. In this paper, we demonstrate that the various observables are all reasonably consistent with each other to within their uncertainties. RCS2 J232727.6-020437 appears to be well relaxed -- with circular and concentric X-ray isophotes, with a cool core, and no indication of significant substructure in extensive galaxy velocity data.Comment: 19 pages, 15 figures, submitted to ApJ on March 5, 2015; in press. Manuscript revised following the referee revie

    Nanometallic Glasses: Size Reduction Brings Ductility, Surface State Drives Its Extent

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    We report tensile experiments on Ni_(80)P_20 metallic glass samples fabricated via a templated electroplating process and via focused ion beam milling, which differed only in their surface energy states: Ga-ion-irradiated and as-electroplated. Molecular dynamics simulations on similar Ni_(80)Al_20 systems corroborate the experimental results, which suggest that the transition from brittle to ductile behavior is driven by sample size, while the extent of ductility is driven by surface state

    Media justice: Madeleine McCann, intermediatization and "trial by media" in the British press

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    Three-year-old Madeleine McCann disappeared on 3 May 2007 from a holiday apartment in Portugal. Over five years and multiple investigations that failed to solve this abducted child case, Madeleine and her parents were subject to a process of relentless ‘intermediatization’. Across 24–7 news coverage, websites, documentaries, films, YouTube videos, books, magazines, music and artworks, Madeleine was a mediagenic image of innocence and a lucrative story. In contrast to Madeleine’s media sacralization, the representation of her parents, Kate and Gerry McCann, fluctuated between periods of vociferous support and prolonged and libellous ‘trial by media’. This article analyses how the global intermediatization of the ‘Maddie Mystery’ fed into and fuelled the ‘trial by media’ of Kate and Gerry McCann in the UK press. Our theorization of ‘trial by media’ is developed and refined through considering its legal limitations in an era of ‘attack journalism’ and unprecedented official UK inquiries into press misconduct and criminality
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