563 research outputs found

    The beginnings of geography teaching and research in the University of Glasgow: the impact of J.W. Gregory

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    J.W. Gregory arrived in Glasgow from Melbourne in 1904 to take up the post of foundation Professor of Geology in the University of Glasgow. Soon after his arrival in Glasgow he began to push for the setting up of teaching in Geography in Glasgow, which came to pass in 1909 with the appointment of a Lecturer in Geography. This lecturer was based in the Department of Geology in the University's East Quad. Gregory's active promotion of Geography in the University was matched by his extensive writing in the area, in textbooks, journal articles and popular books. His prodigious output across a wide range of subject areas is variably accepted today, with much of his geomorphological work being judged as misguided to varying degrees. His 'social science' publications - in the areas of race, migration, colonisation and economic development of Africa and Australia - espouse a viewpoint that is unacceptable in the twenty-first century. Nonetheless, that viewpoint sits squarely within the social and economic traditions of Gregory's era, and he was clearly a key 'Establishment' figure in natural and social sciences research in the first half of the twentieth century. The establishment of Geography in the University of Glasgow remains enduring testimony of J.W. Gregory's energy, dedication and foresight

    Regulation, sensory domains and roles of two Desulfovibrio desulfuricans ATCC27774 Crp family transcription factors, HcpR1 and HcpR2, in response to nitrosative stress

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    In silico analyses identified a Crp/Fnr family transcription factor (HcpR) in sulfate-reducing bacteria that controls expression of the hcp gene, which encodes the hybrid cluster protein and contributes to nitrosative stress responses. There is only one hcpR gene in the model sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough, but two copies in D. desulfuricans 27774, which can use nitrate as an alternative electron acceptor to sulfate. Structures of the D. desulfuricans hcpR1, hcpR2 and hcp operons are reported. We present evidence that hcp expression is regulated by HcpR2, not by HcpR1, and that these two regulators differ in both their DNA-binding site specificity and their sensory domains. HcpR1 is predicted to be a b-type cytochrome. HcpR1 binds upstream of the hcpR1 operon and its synthesis is regulated coordinately with hcp in response to NO. In contrast, hcpR2 expression was not induced by nitrate, nitrite or NO. HcpR2 is an iron-sulfur protein that reacts with NO and O2 . We propose that HcpR1 and HcpR2 use different sensory mechanisms to regulate subsets of genes required for defense against NO-induced nitrosative stress, and that diversification of signal perception and DNA recognition by these two proteins is a product of D. desulfuricans adaptation to its particular environmental niche. This article is protected by copyright. All rights reserved

    Binding of biexcitons in GaAs/AlxGa1-xAs superlattices

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    Binding of the heavy-hole excitons and biexcitons in GaAs/Al0.3Ga0.7As superlattices is studied using linear and nonlinear optical techniques. High biexciton binding energies characteristic of quasi two-dimensional biexcitons are observed in superlattices with considerable miniband dispersion

    Ultrafast Coulomb-induced dynamics of 2D magnetoexcitons

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    We study theoretically the ultrafast nonlinear optical response of quantum well excitons in a perpendicular magnetic field. We show that for magnetoexcitons confined to the lowest Landau levels, the third-order four-wave-mixing (FWM) polarization is dominated by the exciton-exciton interaction effects. For repulsive interactions, we identify two regimes in the time-evolution of the optical polarization characterized by exponential and {\em power law} decay of the FWM signal. We describe these regimes by deriving an analytical solution for the memory kernel of the two-exciton wave-function in strong magnetic field. For strong exciton-exciton interactions, the decay of the FWM signal is governed by an antibound resonance with an interaction-dependent decay rate. For weak interactions, the continuum of exciton-exciton scattering states leads to a long tail of the time-integrated FWM signal for negative time delays, which is described by the product of a power law and a logarithmic factor. By combining this analytic solution with numerical calculations, we study the crossover between the exponential and non-exponential regimes as a function of magnetic field. For attractive exciton-exciton interaction, we show that the time-evolution of the FWM signal is dominated by the biexcitonic effects.Comment: 41 pages with 11 fig

    All the way from … authenticity and distance in world music production

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    World music and the narratives it produces are at the very centre of a formerly transnational production and consumption process. However, the shortened distance between the sites of production and consumption of this good, brought on by migration and greater participation, has created a dilemma for the UK-based artists who perform it: how to maintain authenticity without the added value of ‘distance’. Therefore, the aim of this article is to examine the ways in which musicians and other participants attempt to overcome this problem and in doing so (re)-construct particular aspects of their identity. Rather than being just another critique on authenticity, this article uses distance as an organizing concept in understanding the challenges facing world music production in the UK

    Rescaling employment support accountability: from negative national neoliberalism to positively integrated city-region ecosystems

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    Waves of successive Devolution Deals are transforming England’s landscape of spatial governance and transferring new powers to city-regions, facilitating fundamental qualitative policy reconfigurations and opening up new opportunities as well as new risks for citizens and local areas. Focused on city-region’s recently emerging roles around employment support policies the article advances in four ways what are currently conceptually and geographically underdeveloped literatures on employment support accountability levers. Firstly, the paper dissects weaknesses in the accountability framework of Great Britain’s key national contracted-out employment support programme and identifies the potential for city-regions to respond to these weaknesses. Secondly, the article highlights the centrality of the nationally neglected network accountability lever in supporting these unemployed individuals and advances this discussion further by introducing to the literature for the first time a conceptual distinction between what we term ‘positive’ and ‘negative’ forms of these accountably levers that currently remain homogenised within the literature. Crucially, the argument sets out for the first time in the literature why analytically it is the positive version of network accountability that is the key – and currently missing at national-level – ingredient to the design of effective employment support for the priority group of ‘harder-to-help’ unemployed people who have more complex and/or severe barriers to employment. Thirdly, the paper argues from a geographical perspective that it is city-regions that are uniquely positioned in the English context to create the type of positively networked integrated employment support ‘ecosystem’ that ‘harder-to-help’ individuals in particular require. Finally, the discussion situates these city-region schemes within their broader socio-economic and political context and connects with broader debates around the lurching development of neoliberalism. In doing so it argues that whilst these emerging city-region ecosystem models offer much progressive potential their relationship to the problematic neoliberal employment support paradigm remains uncertain given that they refine, embed and indeed buttress that same neoliberal employment policy paradigm rather than fundamentally challenging or stepping beyond it
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