6,605 research outputs found

    A peer-to-peer infrastructure for resilient web services

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    This work is funded by GR/M78403 ā€œSupporting Internet Computation in Arbitrary Geographical Locationsā€ and GR/R51872 ā€œReflective Application Framework for Distributed Architecturesā€, and by Nuffield Grant URB/01597/G ā€œPeer-to-Peer Infrastructure for Autonomic Storage Architecturesā€This paper describes an infrastructure for the deployment and use of Web Services that are resilient to the failure of the nodes that host those services. The infrastructure presents a single interface that provides mechanisms for users to publish services and to find hosted services. The infrastructure supports the autonomic deployment of services and the brokerage of hosts on which services may be deployed. Once deployed, services are autonomically managed in a number of aspects including load balancing, availability, failure detection and recovery, and lifetime management. Services are published and deployed with associated metadata describing the service type. This same metadata may be used subsequently by interested parties to discover services. The infrastructure uses peer-to-peer (P2P) overlay technologies to abstract over the underlying network to deploy and locate instances of those services. It takes advantage of the P2P network to replicate directory services used to locate service instances (for using a service), Service Hosts (for deployment of services) and Autonomic Managers which manage the deployed services. The P2P overlay network is itself constructed using novel Web Services-based middleware and a variation of the Chord P2P protocol, which is self-managing.Postprin

    Diurnal variation in harbour porpoise detection ā€“ potential implications for management

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    Mapping the sensitivity of split ring resonators using a localized analyte

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    Split ring resonator (SRR) based metamaterials have frequently been demonstrated for use as optical sensors of organic materials. This is made possible by matching the wavelength of the SRR plasmonic resonance with a molecular resonance of a specific analyte, which is usually placed on top of the metal structure. However, systematic studies of SRRs that identify the regions that exhibit a high electric field strength are commonly performed using simulations. In this paper we demonstrate that areas of high electric field strength, termed ā€œhot-spots,ā€ can be found by localizing a small quantity of organic analyte at various positions on or near the structure. Furthermore, the sensitivity of the SRR to the localized analyte can be quantified to determine, experimentally, suitable regions for optical sensing

    New proof-of-concept in viral inactivation: virucidal efficacy of 405Ā nm light against feline calicivirus as a model for norovirus decontamination

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    The requirement for novel decontamination technologies for use in hospitals is ever present. One such system uses 405 nm visible light to inactivate microorganisms via ROS-generated oxidative damage. Although effective for bacterial and fungal inactivation, little is known about the virucidal effects of 405 nm light. Norovirus (NoV) gastroenteritis outbreaks often occur in the clinical setting, and this study was designed to investigate potential inactivation effects of 405 nm light on the NoV surrogate, feline calicivirus (FCV). FCV was exposed to 405 nm light whilst suspended in minimal and organically-rich media to establish the virucidal efficacy and the effect biologically-relevant material may play in viral susceptibility. Antiviral activity was successfully demonstrated with a 4 Log10 (99.99%) reduction in infectivity when suspended in minimal media evident after a dose of 2.8 kJ cmāˆ’2. FCV exposed in artificial faeces, artificial saliva, blood plasma and other organically rich media exhibited an equivalent level of inactivation using between 50ā€“85% less dose of the light, indicating enhanced inactivation when the virus is present in organically-rich biologically-relevant media. Further research in this area could aid in the development of 405 nm light technology for effective NoV decontamination within the hospital environment

    Incidence and severity of respiratory syncytial virus pneumonia in rural Kenyan children identified through hospital surveillance

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    Background.Although necessary for developing a rationale for vaccination, the burden of severe respiratory syncytial virus (RSV) disease in children in resourceā€poor settings remains poorly defined. Methods.We conducted prospective surveillance of severe and very severe pneumonia in children aged <5 years admitted from 2002 through 2007 to Kilifi district hospital in coastal Kenya. Nasal specimens were screened for RSV antigen by immunofluorescence. Incidence rates were estimated for the wellā€defined population. Results.Of 25,149 hospital admissions, 7359 patients (29%) had severe or very severe pneumonia, of whom 6026 (82%) were enrolled. RSV prevalence was 15% (20% among infants) and 27% during epidemics (32% among infants). The proportion of case patients aged 3 months was 65%, and the proportion aged 6 months was 43%. Average annual hospitalization rates were 293 hospitalizations per 100,000 children aged <5 years (95% confidence interval, 271ā€“371 hospitalizations per 100,000 children aged <5 years) and 1107 hospitalizations per 100,000 infants (95% confidence interval, 1012ā€“1211 hospitalizations per 100,000 infants). Hospital admission rates were double in the region close to the hospital. Few patients with RSV infection had lifeā€threatening clinical features or concurrent serious illnesses, and the associated mortality was 2.2%. Conclusions.In this lowā€income setting, rates of hospital admission with RSVā€associated pneumonia are substantial; they are comparable to estimates from the United States but considerably underestimate the burden in the full community. An effective vaccine for children aged >2 months (outside the age group of poor responders) could prevent a large portion of RSV disease. Severity data suggest that the justification for RSV vaccination will be based on the prevention of morbidity, not mortality

    Propagation of Discrete Solitons in Inhomogeneous Networks

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    In many physical applications solitons propagate on supports whose topological properties may induce new and interesting effects. In this paper, we investigate the propagation of solitons on chains with a topological inhomogeneity generated by the insertion of a finite discrete network on the chain. For networks connected by a link to a single site of the chain, we derive a general criterion yielding the momenta for perfect reflection and transmission of traveling solitons and we discuss solitonic motion on chains with topological inhomogeneities

    The tactical mimicry of social enterprise strategies: acting ā€˜as ifā€™ in the everyday life of third sector organizations

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    Using England as a paradigmatic case of the ā€ženterprising up ā€Ÿ of the third sector through social enterprise policies and programs, this article sheds light on resistance as enacted through dramaturgical identification with government strategies. Drawing from a longitudinal qualitative research study, which is interpreted via Michel de Certeauā€Ÿs theory of the everyday, we present the case study of Teak, a charitable regeneration company, to illustrate how its Chief Executive Liam ā€žacted as ā€Ÿ a social entrepreneur in order to gain access to important resources. We establish ā€žtactical mimicry ā€Ÿ as a sensitizing concept to suggest that third sector practitioners ā€Ÿ identification with the normative premises of ā€žsocial enterprise ā€Ÿ is part of a parasitical prosaics geared toward appropriating public money. While tactical mimicry conforms to strategies only in order to exploit them, its ultimate aim is to increase potentials of collective agency outside the direct influence of power. The contribution we make is threefold: first, we extend the recent debate on productive resistance by highlighting how ā€žplaying the game ā€Ÿ without changing existing relations of power can nevertheless produce largely favorable outcomes. Second, we suggest that recognition of the productive potential of tactical mimicry requires methodologies which pay attention to the spatial and temporal dynamics of resistance. And third, we argue that explaining ā€žsocial enterpriseā€Ÿ without consideration of the non-discursive, mainly financial resources made available to those who identify with it, necessarily risks overlooking a crucial element of the dramaturgical dynamic of discourse

    Echolocation detections and digital video surveys provide reliable estimates of the relative density of harbour porpoises

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    Acknowledgements We would like to thank Erik Rexstad and Rob Williams for useful reviews of this manuscript. The collection of visual and acoustic data was funded by the UK Department of Energy & Climate Change, the Scottish Government, Collaborative Offshore Wind Research into the Environment (COWRIE) and Oil & Gas UK. Digital aerial surveys were funded by Moray Offshore Renewables Ltd and additional funding for analysis of the combined datasets was provided by Marine Scotland. Collaboration between the University of Aberdeen and Marine Scotland was supported by MarCRF. We thank colleagues at the University of Aberdeen, Moray First Marine, NERI, Hi-Def Aerial Surveying Ltd and Ravenair for essential support in the field, particularly Tim Barton, Bill Ruck, Rasmus Nielson and Dave Rutter. Thanks also to Andy Webb, David Borchers, Len Thomas, Kelly McLeod, David L. Miller, Dinara Sadykova and Thomas Cornulier for advice on survey design and statistical approache. Data Accessibility Data are available from the Dryad Digital Repository: http://dx.doi.org/10.5061/dryad.cf04gPeer reviewedPublisher PD
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