2,091 research outputs found

    The mineral resources of the English Channel and Thames Estuary

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    This report accompanies the Marine mineral resource map the marine sand and gravel resources of the English Channel and Thames Estuary (Bide et al, 2012). It has been published as part of the research project Mineral Resource Assessment of the UK Continental Shelf commissioned by The Crown Estate. The map is one of a series that covers the UK Continental Shelf (UKCS). Knowledge of mineral resources is essential for effective and sustainable planning decisions. The marine mineral resource maps provide a comprehensive, relevant and accessible information base. This information will allow all stakeholders (planners, industry and members of the public) to visualise the distribution of offshore minerals to a common standard and at a common scale, an important requirement of an integrated marine planning system. The maps will also facilitate the conservation (safeguarding) of non-renewable mineral resources for future generations in accordance with the principles of sustainable development

    'I'd like to know what causes it, you know, anything I've done?' Are we meeting the information and support needs of patients with macular degeneration? A qualitative study

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    Objective: To examine patients' experiences of information and support provision for age-related macular degeneration (AMD) in the UK. Study design: Exploratory qualitative study investigating patient experiences of healthcare consultations and living with AMD over 18 months. Setting: Specialist eye clinics at a Birmingham hospital. Participants: 13 patients diagnosed with AMD. Main outcome measures: Analysis of patients' narratives to identify key themes and issues relating to information and support needs. Results: Information was accessed from a variety of sources. There was evidence of clear information deficits prior to diagnosis, following diagnosis and ongoing across the course of the condition. Patients were often ill informed and therefore unable to self-advocate and recognise when support was needed, what support was available and how to access support. Conclusions: AMD patients have a variety of information needs that are variable across the course of the condition. Further research is needed to determine whether these experiences are typical and identify ways of translating the guidelines into practice. Methods of providing information need to be investigated and improved for this patient group

    Current developments in gene therapy for amyotrophic lateral sclerosis.

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    INTRODUCTION: Amyotrophic lateral sclerosis (ALS) is a devastating adult neurodegenerative disorder characterized by motor neuron degeneration and death around 3 years from onset. So far, riluzole is the only treatment available, although it only offers a slight increase in survival. The complex etiology of ALS, with several genes able to trigger the disease, makes its study difficult. Areas covered: RNA-mediated or protein-mediated toxic gain-of-function leading to motor neuron degeneration appears to be likely common pathogenic mechanisms in ALS. Consequently, gene therapy technologies to reduce toxic RNA and/or proteins and to protect motor neurons by modulating gene expression are at the forefront of the field. Here, we review the most promising scientific advances, paying special attention to the successful treatments tested in animal models as well as analyzing relevant gene therapy clinical trials. Expert opinion: Despite broad advances in target gene identification in ALS and advances in gene therapy technologies, a successful gene therapy for ALS continues to elude researchers. Multiple hurdles encompassing technical, biological, economical and clinical challenges must be overcome before a therapy for patients becomes available. Optimism remains due to positive results obtained in several in vivo studies demonstrating significant disease amelioration in animal models of ALS

    The mineral resources of the East Inshore and East Offshore marine plan areas, southern North Sea

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    Minerals are naturally occurring raw materials essential for the development of a modern economy. However, mineral resources are finite and can only be worked where they occur. As their extraction is subject to many constraints, it is important that society uses minerals in the most efficient and sustainable manner. Identifying the distribution of known mineral resources on the UK Continental Shelf (UKCS) and presenting them in a consistent fashion at a national scale allows minerals to be considered in the marine spatial planning process and permits more effective and sustainable management strategies to be developed. The British Geological Survey (BGS) has undertaken a commission from The Crown Estate to prepare a series of mineral resource maps which cover the UKCS. Mineral resource information was compiled following a desk study of data held by the BGS and external sources. This report summarises the mineral resources depicted on the first of these maps - the East Inshore and East Offshore Marine Plan Areas in the southern North Sea. These are the first areas (Figure 1) for which the Marine Management Organisation is preparing marine plans (MMO, 2010). The map has been produced by the collation and interpretation of a wide range of information, much of which is spatially variable and not always available in a consistent and convenient form. The map depicts mineral resources of current or potential future economic interest in the area. It comprises a 1:500 000 scale map (which accompanies this report) depicting marine aggregate (sand and gravel) resources on the sea bed, and two 1:1 500 000 scale maps (as annexes in this report) depicting coal and evaporite resources at depth beneath the sea bed. These map scales are convenient for the overall display of the data. However, all the data are held digitally at larger scales using a Geographical Information System (GIS), which allows for revision, updating and customisation of the information, together with integration with other datasets

    Boundary Effects on Dynamic Behavior of Josephson-Junction Arrays

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    The boundary effects on the current-voltage characteristics in two-dimensional arrays of resistively shunted Josephson junctions are examined. In particular, we consider both the conventional boundary conditions (CBC) and the fluctuating twist boundary conditions (FTBC), and make comparison of the obtained results. It is observed that the CBC, which have been widely adopted in existing simulations, may give a problem in scaling, arising from rather large boundary effects; the FTBC in general turn out to be effective in reducing the finite-size effects, yielding results with good scaling behavior. To resolve the discrepancy between the two boundary conditions, we propose that the proper scaling in the CBC should be performed with the boundary data discarded: This is shown to give results which indeed scale well and are the same as those from the FTBC.Comment: RevTex, Final version to appear in Phys. Rev.

    Using optical spectroscopy to map the geometry and structure of the irradiated accretion discs in low-mass X-ray binaries:the pilot study of MAXI J0637-430

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    The recurring transient outbursts in low-mass X-ray binaries (LMXBs) provide us with strong test-beds for constraining the poorly understood accretion process. While impossible to image directly, phase-resolved spectroscopy can provide a powerful diagnostic to study their highly complex, time-dependent accretion discs. We present an 8-month long multi-wavelength (UV, optical, X-ray) monitoring campaign of the new candidate black hole LMXB MAXI J0637-430 throughout its 2019/2020 outburst, using the {\em Neil Gehrels Swift Observatory}, as well as three quasi-simultaneous epochs of Gemini/GMOS optical spectroscopy. We find evidence for the existence of a correlation between the X-ray irradiation heating the accretion disc and the evolution of the He {\sc ii} 4686 \AA emission line profiles detected in the optical spectra. Our results demonstrate a connection between the line emitting regions and physical properties of the X-ray irradiation heating the discs during outburst cycles of LMXBs. Further, we are able to show that changes in the physical properties of the irradiation heating the disc in outburst can be imprinted within the H/He emission line profiles themselves in these systems.Comment: 23 pages (including 3 appendices), 10 figures, supplementary figures included in the appendices, accepted for publication in MNRA

    Dynamics of earthquake nucleation process represented by the Burridge-Knopoff model

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    Dynamics of earthquake nucleation process is studied on the basis of the one-dimensional Burridge-Knopoff (BK) model obeying the rate- and state-dependent friction (RSF) law. We investigate the properties of the model at each stage of the nucleation process, including the quasi-static initial phase, the unstable acceleration phase and the high-speed rupture phase or a mainshock. Two kinds of nucleation lengths L_sc and L_c are identified and investigated. The nucleation length L_sc and the initial phase exist only for a weak frictional instability regime, while the nucleation length L_c and the acceleration phase exist for both weak and strong instability regimes. Both L_sc and L_c are found to be determined by the model parameters, the frictional weakening parameter and the elastic stiffness parameter, hardly dependent on the size of an ensuing mainshock. The sliding velocity is extremely slow in the initial phase up to L_sc, of order the pulling speed of the plate, while it reaches a detectable level at a certain stage of the acceleration phase. The continuum limits of the results are discussed. The continuum limit of the BK model lies in the weak frictional instability regime so that a mature homogeneous fault under the RSF law always accompanies the quasi-static nucleation process. Duration times of each stage of the nucleation process are examined. The relation to the elastic continuum model and implications to real seismicity are discussed.Comment: Title changed. Changes mainly in abstract and in section 1. To appear in European Physical Journal

    Edge effects in a frustrated Josephson junction array with modulated couplings

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    A square array of Josephson junctions with modulated strength in a magnetic field with half a flux quantum per plaquette is studied by analytic arguments and dynamical simulations. The modulation is such that alternate columns of junctions are of different strength to the rest. Previous work has shown that this system undergoes an XY followed by an Ising-like vortex lattice disordering transition at a lower temperature. We argue that resistance measurements are a possible probe of the vortex lattice disordering transition as the linear resistance RL(T)A(T)/LR_{L}(T)\sim A(T)/L with A(T)(TTcI) A(T) \propto (T-T_{cI}) at intermediate temperatures TcXY>T>TcIT_{cXY}>T>T_{cI} due to dissipation at the array edges for a particular geometry and vanishes for other geometries. Extensive dynamical simulations are performed which support the qualitative physical arguments.Comment: 8 pages with figs, RevTeX, to appear in Phys. Rev.
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