50 research outputs found

    Quantitative Characterization of Event Streams in Analysis of Hard Real-Time Applications

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    Many real-time embedded systems process event streams that are composed of a finite number of different event types. Each different event type on the stream would typically impose a different workload to the system, and thus the knowledge of possible correlations and dependencies between the different event types could be exploited to get tighter analytic performance bounds of the complete system. We propose an abstract stream model to characterize such an event stream. The model captures the needed information of all possible traces of a class of event streams. Hence, it can be used to obtain hard bounded worst-case and best-case analysis results of a system. We show how the proposed abstract stream model can be obtained from a concrete stream specification, and how it can be used for performance analysis. The applicability of our approach and its advantages over traditional worst-case performance analysis are shown in a case study of a multimedia applicatio

    Isolation of Lagos Bat Virus from Water Mongoose

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    One-sentence summary for table of contents: Lagos bat virus from water mongoose showed strong sequence homology with other Lagos bat virus isolates from South Africa

    The epidemiology of rabies in Zimbabwe. 1. Rabies in dogs (Canis familiaris)

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    The epidemiology of rabies in dogs in Zimbabwe is described using data from 1950, when rabies was re-introduced after a 37 -year absence, to 1996. Dogs constituted 45,7% of all laboratory-confirmed rabies cases and were the species most frequently diagnosed with the disease. Slightly more cases were diagnosed from June to November than in other months. From 1950 to the early 1980s, most dog cases were recorded from commercial farming areas, but since the early 1980s most have been recorded from communal (subsistence farming) areas. This change appears to be due to improved surveillance in communal areas and not to any change in the prevalence of rabies. Dog rabies therefore appears to be maintained mainly in communal area dog populations, particularly the large communal area blocks. Urban rabies was not important except in the city of Mutare. Where dog rabies prevalence was high, the disease was cyclic with periods between peak prevalence ranging from 4- 7 years. Dog rabies cases were, on the whole, independent of jackal rabies and rabies in other carnivores. There was a significant negative relationship between the annual number of rabies vaccine doses administered nationally to dogs and the annual number of dog rabies cases lagged by one year, indicating that the past levels of immunisation coverage have had a significant effect on the number of rabies cases. However, dog vaccination coverage has clearly not been adequate to prevent the regular occurrence of rabies in dogs.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

    The epidemiology of rabies in Zimbabwe. 2. Rabies in jackals (Canis adustus and Canis mesomelas)

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    The epidemiology of rabies in Canis adustus (the side-striped jackal) and Canis mesomelas (the black-backed jackal) in Zimbabwe is described using data collected from 1950-1996. Cases in the two species made up 25,2% of all confirmed cases, second only to domestic dogs. Since the species of jackal cases was not recorded on rabies submission forms, the country was divided into areas according to species dominance and jackal cases were assigned to either C. adustus or C. mesomelas dominant zones or a sympatric zone where the relative status of the species is not known. Jackal rabies in both species is maintained in the commercial farming sector. Jackal rabies in the C. adustus zone occurs as dense epidemics, which begin at a single focus and spread centrifugally. The foci were initiated by rabid dogs, but once initiated the epidemic is maintained by C. adustus independently of other species. The extent of outbreaks in the C. adustus zone was limited by geographical (Ianduse type and jackal species interface) boundaries. Jackal rabies in C. adustus zones showed two seasonal peaks with the main peak occurring during late summer and the second peak during winter. In the C. mesomelas zone jackal rabies was more sparse but it occurred during most years. C. mesomelas is also able to maintain rabies independently of other species, although the epidemiology of the disease in this species is unclear. Transmission of rabies cycles between the two jackal species zones does not appear to occur as epidemics terminate when crossing the C. adustus and C. mesomelas interface boundaries.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

    Renewed global partnerships and redesigned roadmaps for rabies prevention and control

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    Canine rabies, responsible for most human rabies deaths, is a serious global public health concern. This zoonosis is entirely preventable, but by focusing solely upon rabies prevention in humans, this "incurable wound" persists at high costs. Although preventing human deaths through canine rabies elimination is feasible, dog rabies control is often neglected, because dogs are not considered typical economic commodities by the animal health sector. Here, we demonstrate that the responsibility of managing rabies falls upon multiple sectors, that a truly integrated approach is the key to rabies elimination, and that considerable progress has been made to this effect. Achievements include the construction of global rabies networks and organizational partnerships; development of road maps, operational toolkits, and a blueprint for rabies prevention and control; and opportunities for scaling up and replication of successful programs. Progress must continue towards overcoming the remaining challenges preventing the ultimate goal of rabies elimination

    Antigenic characterisation of lyssaviruses in South Africa

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    There are at least six Lyssavirus species that have been isolated in Africa, which include classical rabies virus, Lagos bat virus, Mokola virus, Duvenhage virus, Shimoni bat virus and Ikoma lyssavirus. In this retrospective study, an analysis of the antigenic reactivity patterns of lyssaviruses in South Africa against a panel of 15 anti-nucleoprotein monoclonal antibodies was undertaken. A total of 624 brain specimens, collected between 2005 and 2009, confirmed as containing lyssavirus antigen by direct fluorescent antibody test, were subjected to antigenic differentiation. The lyssaviruses were differentiated into two species, namely rabies virus (99.5%) and Mokola virus (0.5%). Furthermore, rabies virus was further delineated into two common rabies biotypes in South Africa: canid and mongoose. Initially, it was found that the canid rabies biotype had two reactivity patterns; differential staining was observed with just one monoclonal antibody. This difference was likely to have been an artefact related to sample quality, as passage in cell culture restored staining. Mongoose rabies viruses were more heterogeneous, with seven antigenic reactivity patterns detected. Although Mokola viruses were identified in this study, prevalence and reservoir host species are yet to be established. These data demonstrate the usefulness of monoclonal antibody typing panels in lyssavirus surveillance with reference to emergence of new species or spread of rabies biotypes to new geographic zones.This work was partly funded by the Rabies Diagnostic Project, Onderstepoort Veterinary Research Institute (OVI 15/4/P001) and the European Virus Archive (EVA) (04/17/C215).http://www.ojvr.orgam201

    Wildlife rabies in perspective

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    Populations of a number of species of the orders Carnivora and Chiroptera maintain independent rabies epidemics in different parts of the world. However, in large parts of Africa, Asia, and Latin America, rabid dogs outnumber diagnosed wildlife cases. Rabies virus variants circulating in different host populations can be distinguished by the use of monoclonal antibodies and by genomic analysis. Rabies virus strains and their hosts have to be co-adapted in order to allow their prolonged co-existence.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

    Mokola Virus in Domestic Mammals, South Africa

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    We recently identified 2 Mokola viruses from domestic mammals (a dog and a cat) in South Africa. These cases occurred 8 years after the last reported case of infection with this virus. Our findings emphasize the endemicity of rabies-related lyssaviruses in South Africa and the need to better understand the epidemiology of Mokola viruses

    The delivery of oral rabies vaccines to dogs : an African perspective

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    Dog rabies control relies principally on the mass immunization of dogs in order to achieve population immunity levels sufficient to inhibit rabies transmission. In Africa, such high levels of population immunity are rarely achieved due to a number of reasons. Oral immunization has been shown to be an effective means of inducing high levels of immunity in fox populations in several European countries, and this technique has been mooted as a means of overcoming the logistical problems of delivering injectable rabies vaccines to dogs. This paper discusses the requirements for oral rabies vaccines for dogs in Africa and reviews the trials performed to date on baits and baiting systems suitable for the delivery of such vaccines. Issues affecting possible rabies vaccine distribution in the future are discussed and the major research issues still to be tackled are summarized.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201
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