3,206 research outputs found

    Compactness of derivations from commutative Banach algebras

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    We consider the compactness of derivations from commutative Banach algebras into their dual modules. We show that if there are no compact derivations from a commutative Banach algebra, AA, into its dual module, then there are no compact derivations from AA into any symmetric AA-bimodule; we also prove analogous results for weakly compact derivations and for bounded derivations of finite rank. We then characterise the compact derivations from the convolution algebra â„“1(Z+)\ell^1(\Z_+) to its dual. Finally, we give an example (due to J. F. Feinstein) of a non-compact, bounded derivation from a uniform algebra AA into a symmetric AA-bimodule

    Once upon a time there was a consumer…: stories of magic and the magic of stories

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    This paper explores how the centrality of narrative to people’s understandings of the world, and the power of stories of enchantment in particular, colour consumer culture. Specifically, it analyses the ways in which fantastic themes of magic and heroism are used in the discourses of marketing scholars and practitioners, as well as consumers to shape views of consumption and marketing. It further illuminates the role that marketers and consumers each have in imbuing consumption with a sense of enchantment and situates this phenomenon within the dominant neoliberal ideology. Finally, it discusses implications for marketing theory and for practices aimed at reducing excessive consumption related to such enchantment

    Electroencephalographic evidence of vector inversion in antipointing

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    Mirror-symmetrical reaching movements (i.e., antipointing) produce a visual-field-specific pattern of endpoint bias consistent with a perceptual representation of visual space (Heath et al. in Exp Brain Res 192:275-286, 2009a; J Mot Behav 41:383-392 2009b). The goal of the present investigation was to examine the concurrent behavioural and event-related brain potentials (ERP) of pro- and antipointing to determine whether endpoint bias in the latter task is related to a remapping of the environmental parameters of a target (i.e., vector inversion hypothesis) or a shift of visual attention from a veridical to a cognitively represented target location (i.e., reallocation of attention hypothesis). As expected, results for antipointing-but not propointing-yielded a visual-field-specific pattern of endpoint bias. In terms of the ERP findings, an early component (i.e., the N100) related to the orienting of visuospatial attention was comparable across pro- and antipointing. In contrast, a later occurring component (i.e., the P300) demonstrated a reliable between-task difference in amplitude. Notably, the P300 has been linked to the revision of a 'mental model' when a mismatch is noted between a stimulus and a required task goal (so-called context-updating). Thus, we propose that the between-task difference in the P300 indicates that antipointing is associated with a remapping of a target's veridical location in mirror-symmetrical space (i.e., vector inversion). Moreover, our combined behavioural and ERP findings provide evidence that vector inversion is mediated via perception-based visual networks

    Postal survey of contacts between cattle farms on the Isle of Lewis

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    The British Cattle Movement Service (BCMS) database contains an unprecedented quantity of data on the movement of cattle within the UK. These data may be used to construct models of the contact structure of the UK cattle herd, for epidemiological purposes. There are two significant potential sources of inaccuracy within such models: movements that are not reported or are reported inaccurately to the BCMS, and contacts between farms that might transmit infection, but are not animal movements. This field study addressed these issues. Cattle farmers on the Isle of Lewis were recruited with the assistance of the local veterinary surgeon, and asked to record a range of potential risk behaviours for a one-month period. They were also asked questions about husbandry practices on their farm. Comparison of the BCMS contact data with that reported by Lewis' farmers highlighted use of common grazing land as a significant source of contact, and potential disease transmission, between cattle that currently goes unreported; around half of responding holdings on Lewis use common grazing land at some point during the year, and these movements are not reported to the BCMS

    REALIZATION OF A DC MICROGRID USING A HAMILTONIAN BASED CONTROLS SOLUTION

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    Future power grids are envisioned to be serviced by heterogeneous arrangements of renewable energy sources. Due to their stochastic nature, energy storage distribution and management are pivotal in realizing microgrids serviced heavily by renewable energy assets. Identifying the required response characteristics to meet the operational requirements of a power grid are of great importance and must be illuminated in order to discern optimal hardware topologies. Hamiltonian Surface Shaping and Power Flow Control (HSSPFC) presents the tools to identify such characteristics. By using energy storage as actuation within the closed loop controller, the response requirements may be identified while providing a decoupled controller solution. A DC microgrid servicing a fixed RC load through source and bus level storage managed by HSSPFC was realized in hardware. A procedure was developed to calibrate the DC microgrid architecture of this work to the reduced order model used by the HSSPFC law. Storage requirements were examined through simulation and experimental testing. Bandwidth contributions between feed forward and PI components of the HSSPFC law are illuminated and suggest the need for well-known system losses to prevent the need for additional overhead in storage allocations. The following work outlines the steps taken in realizing a DC microgrid and presents design considerations for system calibration and storage requirements per the closed loop controls for future DC microgrids

    A tale of two countries: Brexit and the ‘left behind’ thesis

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    Why did Britain vote for Brexit and what was the relative importance of social class, age, and immigration in determining the result? Using aggregate level data, Matthew Goodwin and Oliver Heath outline some of the key factors that accounted for the overall Leave victory and the variation in support experienced across different geographic areas

    Why Theresa May's gamble at the polls failed

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    What was the impact of Brexit on the 2017 general election result? What difference did the collapse of UKIP make? And what was the relative importance of factors such as turnout, education, age, and ethnic diversity on support for the two main parties? In a new article forthcoming in Political Quarterly, Oliver Heath and Matthew Goodwin answer these questions

    Brexit and the left behind: a tale of two countries

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    Why did Britain vote for Brexit? What was the relative importance of social class, age, and immigration? And to what extent did the vote for Brexit map on to past campaigns by the UK Independence Party? To answer these questions, Matthew Goodwin and Oliver Heath used aggregate-level data to analyse the Brexit vote in a paper forthcoming in Political Quarterly. They summarise the findings

    UK 2017 General Election vote examined: income, poverty and Brexit

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