879 research outputs found

    Re-negotiating Ideologies of Bilingualism on the Margins of Education

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    This article reports on an ethnographic study carried out in three interrelated sites: two contrasting secondary schools and a Youth-Club (the principal focus of this article), in an area of southwest Wales. This article highlights the incongruence between the language at home and the language of the school and posits that the relationship between language use at school and in the wider community needs to be problematised and questioned far more than has been done thus far. This study questions whether school-based ideologies and school-based practices are re-negotiated or contested on the margins of education and whether this re-negotiation and contestation plays an important role in whether a young person chooses to use Welsh or English outside of school. It will be argued that recreational spaces, even though loosely connected to schools as institutions, function as more open spaces where institutional ideologies are actively reworked and renegotiated, either through choosing to use English or by mixing and blending different aspects of linguistic resources, or by re-negotiating and questioning which version of Welshness is more valuable, ‘the removed and authentic’ (as seen at the Welsh school) or the ‘new and hybrid’ as seen at the Youth-Club

    Enhanced conformational space sampling improves the prediction of chemical shifts in proteins.

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    A biased-potential molecular dynamics simulation method, accelerated molecular dynamics (AMD), was combined with the chemical shift prediction algorithm SHIFTX to calculate (1)H(N), (15)N, (13)Calpha, (13)Cbeta, and (13)C' chemical shifts of the ankyrin repeat protein IkappaBalpha (residues 67-206), the primary inhibitor of nuclear factor kappa-B (NF-kappaB). Free-energy-weighted molecular ensembles were generated over a range of acceleration levels, affording systematic enhancement of the conformational space sampling of the protein. We have found that the predicted chemical shifts, particularly for the (15)N, (13)Calpha, and (13)Cbeta nuclei, improve substantially with enhanced conformational space sampling up to an optimal acceleration level. Significant improvement in the predicted chemical shift data coincides with those regions of the protein that exhibit backbone dynamics on longer time scales. Interestingly, the optimal acceleration level for reproduction of the chemical shift data has previously been shown to best reproduce the experimental residual dipolar coupling (RDC) data for this system, as both chemical shift data and RDCs report on an ensemble and time average in the millisecond range

    Distinct ubiquitin binding modes exhibited by SH3 domains: Molecular determinants and functional implications

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    SH3 domains constitute a new type of ubiquitin-binding domains. We previously showed that the third SH3 domain (SH3-C) of CD2AP binds ubiquitin in an alternative orientation. We have determined the structure of the complex between first CD2AP SH3 domain and ubiquitin and performed a structural and mutational analysis to decipher the determinants of the SH3-C binding mode to ubiquitin. We found that the Phe-to-Tyr mutation in CD2AP and in the homologous CIN85 SH3-C domain does not abrogate ubiquitin binding, in contrast to previous hypothesis and our findings for the first two CD2AP SH3 domains. The similar alternative binding mode of the SH3-C domains of these related adaptor proteins is characterised by a higher affinity to C-terminal extended ubiquitin molecules. We conclude that CD2AP/CIN85 SH3-C domain interaction with ubiquitin constitutes a new ubiquitin-binding mode involved in a different cellular function and thus changes the previously established mechanism of EGF-dependent CD2AP/CIN85 mono-ubiquitination. © 2013 Ortega Roldan et al

    Edulingualism: linguistic repertoires, academic tasks and student agency in an English-dominant university

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    This article reports on a study that examined how a group of plurilingual students use their linguistic repertoires to achieve a number of purposes such as performing identity, learning and socialising, and negotiating with structure in an English-dominant university. In order to capture the dynamic relationship between language-as-resource, academic tasks and agency in this particular context, the article proposes ‘edulingualism’ as a conceptual and analytic lens. To this end, the article examines multiple data sets (narratives, reflective accounts, recorded interactions and texts) that show how, by mobilising their multilingual resources, these students achieve their purposes and take ownership of their learning experiences within a monolingual learning space

    Tides on Other Earths: Implications for Exoplanet and Palaeo-Tidal Simulations

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    A key controller of a planet's rotational evolution, and hence habitability, is tidal dissipation, which on Earth is dominated by the ocean tides. Because exoplanet or deep‐time Earth topographies are unknown, a statistical ensemble is used to constrain possible tidal dissipation rates on an Earth‐like planet. A dedicated tidal model is used together with 120 random continental configurations to simulate Earth's semidiurnal lunar tide. The results show a possible ocean tidal dissipation range spanning 3 orders of magnitude, between 2.3 GWto 1.9 TW (1 TW=1012 W). When model resolution is considered, this compares well with theoretical limits derived for the energetics of Earth's present‐day deep ocean. Consequently, continents exert a fundamental control on tidal dissipation rates and we suggest that plate tectonics on a planet will induce a time‐varying dissipation analogous to Earth's. This will alter rotational periods over millions of years and further complicate the role of tides for planetary evolution. Plain Language Summary The daylength of a planet is key for habitability because it regulates the rate with which solar radiation is received and redistributed at the surface. A main controller of a planet's daylength is the ocean tide, because the dissipation of tidal energy works as a brake on the planet's spin, increasing the daylength. Tides are sensitive to the continental arrangement on a planet, but there are no details of the surface of any exoplanet and only limited information of what Earth looked like in the distant past. The change in Earth's daylength forces the Moon to recede into a higher orbit, but the present‐day recession rate is very high and does not fit our age models of the moon, implying that the tides must have been much weaker in the distant past. Here, we use a series of tidal predictions for random continental configurations of Earth to provide a range of tidal dissipation rates and thus an estimate of how the tides in the deep past may have evolved as Earth's continents grew more and more complex. This research also provides a range of dissipation rates that can be used for simulations of the rotational and orbital evolution of exoplanets
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