1,526 research outputs found
Microstates of a Neutral Black Hole in M Theory
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
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
Increased SK3 expression in DM1 lens cells leads to impaired growth through a greater calcium-induced fragility
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
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
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
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
ASTERIX and 2.0 Knowledge Management : exploring the appropriation of 2.0 KMS via the Myth of the Gaulish village
International audienceKnowledge Management Systems (KMS) in companies have profoundly changed in recent years. They have become KMS 2.0 that aim to transform the firm and are driven by a new relationship to knowledge in line with 2.0 organisations. These 2.0 KMS have implemented modes of organisation that disrupt those that previously guided firms’ performance. This can sometimes lead to paradoxical organizational dysfunctions as witnessed by the difficulties faced by some traditionally hierarchical French companies. Through a case study of Constructor and a theoretical background on IS appropriation in organizations and myths in management, we show how the Asterix myth contributes to understanding how 2.0. KMS are appropriated in such companies. We find evidence of similarities regarding knowledge and Knowledge Management between the Asterix’ myth and the behaviours and practices concerning knowledge management within Constructor. As a result, the Asterix’ myth may be a relevant perspective for understanding the obstacles, advantages and appropriations of 2.0. KMS within French organizations
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Review Article: When 'life itself' goes to work: Reviewing shifts in organizational life through the lens of biopower
This review article suggests the English publication of Foucault’s lectures on biopower, The Birth of Biopolitics (2008), might be useful for extending our understandings of how organizational power relations have changed over the last 20 years. Unlike disciplinary power, which constrains and delimits individuals, the concept of biopower emphasizes how our life abilities and extra-work qualities (bios or ‘life itself’) are now key objects of exploitation – particularly under neoliberalism. The term biocracy is introduced to analyse recent reports on workplace experiences symptomatic of biopower. Finally, the conceptual weaknesses of biopower for organizational theorizing are critically evaluated to help develop the idea for future scholarship
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