319 research outputs found

    Mapping Orientalism: Representations and Pedagogies

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    In order to understand Orientalism it is necessary to realize, as Vincent T. Harlow has noted, that there were “two British empires.” The first empire consisted of the colonies in America and the West Indies and was established in the seventeenth century, with the explorations in the Pacific, and the trading networks that developed with Asia and Africa. The “second British empire” dates from 1783 and resulted from the loss of America, which in turn forced Britain to formulate new ideas about and approaches to its empire. The Colonial Office was set up in 1801, and, as Harlow observed, Britain experienced a “Swing to the East,” to India and the Asian colonies (Harlow, 2:1–11)

    A Fubini type theorem for rough integration

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    We develop the integration theory of two-parameter controlled paths YY allowing us to define integrals of the form \begin{equation} \int_{[s,t] \times [u,v]} Y_{r,r'} \;d(X_{r}, X_{r'}) \end{equation} where XX is the geometric pp-rough path that controls YY. This extends to arbitrary regularity the definition presented for 2p<32\leq p<3 in the recent paper of Hairer and Gerasimovi\v{c}s where it is used in the proof of a version of H\"{o}rmander's theorem for a class of SPDEs. We extend the Fubini type theorem of the same paper by showing that this two-parameter integral coincides with the two iterated one-parameter integrals [s,t]×[u,v]Yr,r  d(Xr,Xr)=stuvYr,r  dXr  dXr=uvstYr,r  dXr  dXr. \int_{[s,t] \times [u,v]} Y_{r,r'} \;d(X_{r}, X_{r'}) = \int_{s}^{t} \int_{u}^{v} Y_{r,r'} \;dX_{r'} \;dX_{r'} = \int_{u}^{v} \int_{s}^{t} Y_{r,r'} \;dX_{r} \;dX_{r'}. A priori these three integrals have distinct definitions, and so this parallels the classical Fubini's theorem for product measures. By extending the two-parameter Young-Towghi inequality in this context, we derive a maximal inequality for the discrete integrals approximating the two-parameter integral. We also extend the analysis to consider integrals of the form \begin{equation*} \int_{[s,t] \times [u,v]} Y_{r,r'} \; d(X_{r}, \tilde{X}_{r'}) \end{equation*} for possibly different rough paths XX and X~\tilde{X}, and obtain the corresponding Fubini type theorem. We prove continuity estimates for these integrals in the appropriate rough path topologies. As an application we consider the signature kernel, which has recently emerged as a useful tool in data science, as an example of a two-parameter controlled rough path which also solves a two-parameter rough integral equation.Comment: 40 page

    A Multi-Code Analysis Toolkit for Astrophysical Simulation Data

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    The analysis of complex multiphysics astrophysical simulations presents a unique and rapidly growing set of challenges: reproducibility, parallelization, and vast increases in data size and complexity chief among them. In order to meet these challenges, and in order to open up new avenues for collaboration between users of multiple simulation platforms, we present yt (available at http://yt.enzotools.org/), an open source, community-developed astrophysical analysis and visualization toolkit. Analysis and visualization with yt are oriented around physically relevant quantities rather than quantities native to astrophysical simulation codes. While originally designed for handling Enzo's structure adaptive mesh refinement (AMR) data, yt has been extended to work with several different simulation methods and simulation codes including Orion, RAMSES, and FLASH. We report on its methods for reading, handling, and visualizing data, including projections, multivariate volume rendering, multi-dimensional histograms, halo finding, light cone generation and topologically-connected isocontour identification. Furthermore, we discuss the underlying algorithms yt uses for processing and visualizing data, and its mechanisms for parallelization of analysis tasks.Comment: 18 pages, 6 figures, emulateapj format. Resubmitted to Astrophysical Journal Supplement Series with revisions from referee. yt can be found at http://yt.enzotools.org

    Reconceptualising temporality in young lives: exploring young people’s current and future livelihoods in AIDS-affected southern Africa

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    In recent years, anxieties have been expressed that the impacts of southern Africa's AIDS pandemic on young people today will damage their future livelihood prospects. Geographers have been remarkably reluctant to explore young people's future livelihoods, inspired by a concern to view young people as human beings, worthy of study in their own right rather than mere human becomings, of interest only as ‘adults in the making’. Yet there is growing acknowledgement that young people, like older people, are always both ‘being and becoming’. The connections between current and future lives merit much greater attention, both because experiences and actions in childhood and youth undoubtedly shape the futures of individuals and wider society, but also because young people's thoughts and actions are so often geared to the future, and this future orientation shapes their present worlds. This paper reports on research that set out to explore links between the impacts of AIDS and young people's livelihood prospects. Intensive case study research was undertaken, combining participatory methods and life history interviews with young people aged 10–24 in two villages, one in southern Malawi and the other in the mountains of Lesotho. By theorising a temporal dimension to de Haan and Zoomers’ concept of livelihood trajectories, the paper focuses on the ways in which young people respond to both the immediate sustenance requirements of themselves and their households and their need to accrue assets for future livelihoods. Some young people's trajectories appear to be disturbed by the influence of AIDS, but with no systematic patterns. Beyond addressing empirical questions concerning the impacts of AIDS, the paper contributes to our understanding of how livelihoods are produced and to the conceptualisation of youth transitions as produced through the iteration of present and future

    Gold nanorod reshaping in vitro and in vivo using a continuous wave laser

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    Funding for this project was provided by ERC grant 242991 (D. Elson), and by Cancer Research UK via the CRUK Cancer Imaging Centre at the Institute of Cancer Research (ICR) to J. Bamber. We acknowledge an ERC starting grant (project number 257182) to A. Porter, and BRC funding (project number P46143) to A. Porter, D. Elson and P. Ruenraroengsak. We acknowledge NHS funding to the NIHR Biomedical Research Centre at The Royal Marsden (J. Bamber) and at Imperial College London, as well as support provided by the Cancer Research UK Imperial Centre.Gold nanorods (GNRs) are increasingly being investigated for cancer theranostics as they possess features which lend themselves in equal measures as contrast agents and catalysts for photothermal therapy. Their optical absorption spectral peak wavelength is determined by their size and shape. Photothermal therapy using GNRs is typically established using near infrared light as this allows sufficient penetration into the tumour matrix. Continuous wave (CW) lasers are the most commonly applied source of near infrared irradiation on GNRs for tumour photothermal therapy. It is perceived that large tumours may require fractionated or prolonged irradiation. However the true efficacy of repeated or protracted CW irradiation on tumour sites using the original sample of GNRs remains unclear. In this study spectroscopy and transmission electron microscopy are used to demonstrate that GNRs reshape both in vitro and in vivo after CW irradiation, which reduces their absorption efficiency. These changes were sustained throughout and beyond the initial period of irradiation, resulting from a spectral blue-shift and a considerable diminution in the absorption peak of GNRs. Solid subcutaneous tumours in immunodeficient BALB/c mice were subjected to GNRs and analysed with electron microscopy pre- and post-CW laser irradiation. This phenomenon of thermally induced GNR reshaping can occur at relatively low bulk temperatures, well below the bulk melting point of gold. Photoacoustic monitoring of GNR reshaping is also evaluated as a potential clinical aid to determine GNR absorption and reshaping during photothermal therapy. Aggregation of particles was coincidentally observed following CW irradiation, which would further diminish the subsequent optical absorption capacity of irradiated GNRs. It is thus established that sequential or prolonged applications of CW laser will not confer any additional photothermal effect on tumours due to significant attenuations in the peak optical absorption properties of GNRs following primary laser irradiation.Publisher PDFPeer reviewe

    Clinical, angiographic and procedural correlates of quantitative coronary dimensions after directional coronary atherectomy

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    AbstractTo define the clinical, angiographic and procedural correlates of quantitative coronary dimensions after directional coronary atherectomy, 400 lesions in 378 patients were analyzed with use of qualitative morphologic and quantitative angiographic methods. Successful atherectomy, defined by a <75% residual area stenosis, tissue retrieval and the absence of in-hospital ischemic complications, was performed in 351 lesions (87.7%). After atherectomy, minimal cross-sectional area increased from 1.2 ± 1.1 to 6.6 ± 4.4 mm2(p < 0.001) and percent area stenosis was reduced from 87 ± 10% to 31 ± 42% (p < 0.001).By univariate analysis, device size (p < 0.001) and left circumflex artery lesion location (p = 0.004) were associated with a larger final minimal cross-sectional area. Conversely, restenotic lesion (p = 0.002), lesion length ≥ 10 mm (p = 0.018) and lesion calcification (p = 0.035) were quantitatively associated with a smaller final minimum cross-sectional area. With use of stepwise multivariate analysis to control for the reference area, atherectomy device size (p = 0.003) and left circumflex lesion location (p = 0.007) were independently associated with a larger final minimal cross-sectional area, whereas restenotic lesion (p = 0.010), diffuse proximal disease (p = 0.033), lesion length ≥ 10 mm (p = 0.026) and lesion calcification (p = 0.081) were significantly correlated with a smaller final minimal cross-sectional area. The number of specimens excised, the number of atherectomy passes and atherectomy balloon inflation pressure did not correlate with the final minimal cross-sectional area.Thus, directional atherectomy results in marked improvement of coronary lumen dimensions, at least in part correlated with the presence of certain clinical, angiographic and procedural factors at the time of atherectomy
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