1,618 research outputs found

    Microstates of a Neutral Black Hole in M Theory

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    We consider vacuum solutions in M theory of the form of a five-dimensional Kaluza-Klein black hole cross T^6. In a certain limit, these include the five-dimensional neutral rotating black hole (cross T^6). From a IIA standpoint, these solutions carry D0 and D6 charges. We show that there is a weakly coupled D-brane description which precisely reproduces the Hawking-Bekenstein entropy in the extremal limit, even though supersymmetry is completely broken.Comment: 11 pages. v2: microstate counting extended to generic angular moment

    Characterizing and modeling the dynamics of online popularity

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    Online popularity has enormous impact on opinions, culture, policy, and profits. We provide a quantitative, large scale, temporal analysis of the dynamics of online content popularity in two massive model systems, the Wikipedia and an entire country's Web space. We find that the dynamics of popularity are characterized by bursts, displaying characteristic features of critical systems such as fat-tailed distributions of magnitude and inter-event time. We propose a minimal model combining the classic preferential popularity increase mechanism with the occurrence of random popularity shifts due to exogenous factors. The model recovers the critical features observed in the empirical analysis of the systems analyzed here, highlighting the key factors needed in the description of popularity dynamics.Comment: 5 pages, 4 figures. Modeling part detailed. Final version published in Physical Review Letter

    What young people want from health-related online resources: a focus group study

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    The growth of the Internet as an information source about health, particularly amongst young people, is well established. The aim of this study was to explore young people's perceptions and experiences of engaging with health-related online content, particularly through social media websites. Between February and July 2011 nine focus groups were facilitated across Scotland with young people aged between 14 and 18 years. Health-related user-generated content seems to be appreciated by young people as a useful, if not always trustworthy, source of accounts of other people's experiences. The reliability and quality of both user-generated content and official factual content about health appear to be concerns for young people, and they employ specialised strategies for negotiating both areas of the online environment. Young people's engagement with health online is a dynamic area for research. Their perceptions and experiences of health-related content seem based on their wider familiarity with the online environment and, as the online environment develops, so too do young people's strategies and conventions for accessing it

    Increased SK3 expression in DM1 lens cells leads to impaired growth through a greater calcium-induced fragility

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    Although cataract is a characteristic feature of myotonic dystrophy type 1 (DM1), little is known of the underlying mechanisms. We generated four lens epithelial cell lines derived from DM1 cataracts and two from age-matched, non-DM cataracts. Small-pool PCR revealed typical large triplet repeat expansions in the DM1 cells. Furthermore, real-time PCR analysis showed reduced SIX5 expression and increased expression of the Ca2+-activated K+ channel SK3 in the DM1 cells. These cells also exhibited longer population doubling times which did not arise through reduced proliferation, but rather increased cell death as shown by increased release of lactate dehydrogenase (LDH). Using 86Rb+ as a tracer for K+, we found no difference in the resting K+ influx or efflux kinetics. In all cases, the ouabain sensitive component of the influx contributed ~50% of the total. However, stimulating internal Ca2+ by exposure to ionomycin not only caused greater stimulation of K+ (86Rb) efflux in the DM1 cells but also induced a higher rate of cell death (LDH assay). Since both the hyper-stimulation of K+ efflux and cell death were reduced by the highly specific SK inhibitor apamin, we suggest that increased expression of SK3 has a critical role in the increased Ca2+-induced fragility in DM1 cells. The present data, therefore, both help explain the lower epithelial cell density previously observed in DM1 cataracts and provide general insights into mechanisms underlying the fragility of other DM1-affected tissues

    No measure for culture? Value in the new economy

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    This paper explores articulations of the value of investment in culture and the arts through a critical discourse analysis of policy documents, reports and academic commentary since 1997. It argues that in this period, discourses around the value of culture have moved from a focus on the direct economic contributions of the culture industries to their indirect economic benefits. These indirect benefits are discussed here under three main headings: creativity and innovation, employability, and social inclusion. These are in turn analysed in terms of three forms of capital: human, social and cultural. The paper concludes with an analysis of this discursive shift through the lens of autonomist Marxist concerns with the labour of social reproduction. It is our argument that, in contemporary policy discourses on culture and the arts, the government in the UK is increasingly concerned with the use of culture to form the social in the image of capital. As such, we must turn our attention beyond the walls of the factory in order to understand the contemporary capitalist production of value and resistance to it. </jats:p

    Training to self-care: fitness tracking, biopedagogy and the healthy consumer

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    In this article, we provide an account of Fitbit, a wearable sensor device, using two complementary analytical approaches: auto-ethnography and media analysis. Drawing on the concept of biopedagogy, which describes the processes of learning and training bodies how to live, we focus on how users learn to self-care with wearable technologies through a series of micropractices that involve processes of mediation and the sharing of their own data via social networking. Our discussion is oriented towards four areas of analysis: data subjectivity and sociality; making meaning; time and productivity and brand identity. We articulate how these micropractices of knowing one’s body regulate the contemporary ‘fit’ and healthy subject, and mediate expertise about health, behaviour and data subjectivity

    Crowdsourced Mapping in Crisis Zones: Collaboration, Organisation and Impact

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    Crowdsourced mapping has become an integral part of humanitarian response, with high profile deployments of platforms following the Haiti and Nepal earthquakes, and the multiple projects initiated during the Ebola outbreak in North West Africa in 2014, being prominent examples. There have also been hundreds of deployments of crowdsourced mapping projects across the globe, that did not have a high profile. This paper, through an analysis of 51 mapping deployments between 2010–2016, complimented with expert interviews, seeks to explore the organisational structures that create the conditions for effective mapping actions, and the relationship between the commissioning body, often a Non-Governmental Organisation (NGO) and the volunteers who regularly make up the team charged with producing the map. The research suggests that there are three distinct areas that need to be improved in-order to provide appropriate assistance through mapping in humanitarian crisis; regionalise; prepare; and research. The paper concludes, based on the case studies, how each of these areas can be handled more effectively, concluding that failure to implement one area sufficiently can lead to overall project failure

    The Managed Prosumer:Evolving Knowledge Strategies in the Design of Information Infrastructures

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    This paper contributes to the reworking of the traditional concepts and methods of Science and Technology Studies that is necessary in order to analyse the development and use of social media and other emerging information infrastructures (IIs). Through long-term studies of the development of two contrasting IIs, the paper examines the prosumer-management strategies by which vendors manage their relationships with their diverse users. Despite the sharp differences between our cases – an online-game with social network features and traditional enterprise systems – we find striking homologies in the ways vendors manage the tensions underpinning the design and development of mass-market products. Thus their knowledge infrastructures – the set of tools and instruments through which vendors maintain an adequate understanding of their multiple users – change in the face of competing exigencies. Market expansion may favour ‘efficient’ quantitative user assessment methods and the construction of abstract user categories for designing new generic solutions and services around market segments. However where a product extends into new and unfamiliar user markets the growing social distance between developer and user may call for ‘richer’ direct ways of knowing the user. We note the emergence of collective fora, which can provide a space for independent action and innovation by users. However, these were managed communities. Certain user relations functions were pushed out to the community or third-party organizations and at other times pulled back in-house – for example, to increase vendor direct control. This picture is far removed from the visions of seamless integration of producers and users encouraged by notions such as prosumer

    Synchronous online CPD: empirical support for the value of webinars in career settings

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    The careers profession in England is facing unprecedented challenges. Initiatives to improve service delivery while keeping costs low are attractive and online training holds the promise of high impact at low cost. The present study employs a qualitative methodology to evaluate a series of online ‘webinars’ conducted with 15 careers advisers. Results showed that the technology itself could impede learning, and participants missed out on the peer-to-peer interaction that takes place in a ‘bricks and mortar’ setting, but overall participants found that access to relevant, good quality training from the convenience of their workplace more than compensated for the challenges. The article offers conceptual support for the viability of online learning through the theory of equivalency, andragogy and transactional distance theory, and makes recommendations for practice
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