263 research outputs found

    Transmission of continuous query results in mobile computing systems

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    Cataloged from PDF version of article.In a mobile computing environment, a user with a wireless connection to the information network can access data via submitting queries to data servers. As the mobility is the most distinguishing feature of the mobile computing paradigm, location becomes an important piece of information for the so-called location-dependent queries, where the answer to a query depends on the current location of the user who issued the query. A location-dependent query submitted by a mobile user can become more difficult to process when it is submitted as a continuous query (CQ) for which the answer changes as the user moves. The answer to a location-dependent CQ can be provided as a set of tuples [S, begin, end] indicating that object S is the answer of the query from time begin to time end. Once the tuples in the answer set are determined, the next step is to determine the transmission time of these tuples to the user. Transmission time of tuples is critical in the sense that it can have a considerable impact on both the communication overhead imposed on the wireless network and the availability of tuples in case of disconnections. In this paper, we propose three tuple transmission approaches that can be used to determine the transmission time of tuples in the answer set of a location-dependent CQ. We also evaluate the relative performance of the proposed approaches under different settings of environmental parameters. (C) 2000 Elsevier Science Inc. All rights reserved

    Pedal curves, orthotomics and catacaustics of frontals in the hyperbolic 2-space

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    In this paper, firstly the definition of the pedal curves of spacelike frontals is presented. The parametric representation of pedal curves of spacelike frontals is given by using the hyperbolic Legendrian moving frames along these frontals. We mainly deal with the classification and recognition problems of singularities of hyperbolic pedal curves of spacelike frontals constructed by non-singular and singular dual curve germs in hyperbolic 2-space. We show that for non-singular dual curve germs one can determine singularity types of such pedal curves based on singularities of the first spacelike hyperbolic Legendrian curvature germs and locations of pedal points. On the other hand, for singular dual curve germs, singularity types of pedal curves depend upon singularities of both of the spacelike hyperbolic Legendrian curvature germs and also locations of pedal points. Then, after introducing orthotomics of spacelike frontals we present some relationships of such curves with hyperbolic pedal curves. Finally, we present an application to light patterns generated by reflected rays in hyperbolic plane. The theory investigated in the paper is supported by illustrated examples

    Endothelial function in patients with familial Mediterranean fever-related amyloidosis and association with cardiovascular events

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    Objectives. Secondary amyloidosis is the most important complication of FMF and endothelial function is more severely impaired. Elevated asymmetric dimethyl arginine (ADMA) may mediate the excess cardiovascular disease (CVD) risk of this group. We aimed to compare endothelial function characteristics, including ADMA, in patients with FMF-related amyloidosis and primary glomerulopathies and to define risk factors for a CVD event. Methods. We undertook a cross-sectional study with prospective follow-up including consecutive patients with FMF-related amyloidosis (n = 98) or other non-diabetic glomerulopathies (n = 102). All patients had nephrotic-range proteinuria and normal glomerular filtration rate. Flow-mediated dilatation (FMD) was assessedand ADMA levels, CRP and pentraxin 3 (PTX3) were determined. Patients were followed for cardiovascular events. Results. Amyloidosis patients secondary to FMF showed higher levels of ADMA, CRP and PTX3 and lower FMD as compared with patients with other glomerulopathies. Cardiovascular events (n = 54) were registered during 3 years of follow-up. Increased ADMA levels and lower FMD were observed in patients with cardiovascular risk in both groups, but especially in individuals with amyloidosis.Conclusion. Patients with FMF-related amyloidosis have increased CVD event risk, probably related to the high ADMA levels, elevated inflammatory markers and decreased FMD measures observed in these patients

    Newly discovered mutations in the GALNT3 gene causing autosomal recessive hyperostosis-hyperphosphatemia syndrome

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    Background and purpose Periosteal new bone formation and cortical hyperostosis often suggest an initial diagnosis of bone malignancy or osteomyelitis. In the present study, we investigated the cause of persistent bone hyperostosis in the offspring of two consanguineous parents

    Reviewing the literature on access to prompt and effective malaria treatment in Kenya: implications for meeting the Abuja targets

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    <p>Abstract</p> <p>Background</p> <p>Effective case management is central to reducing malaria mortality and morbidity worldwide, but only a minority of those affected by malaria, have access to prompt effective treatment.</p> <p>In Kenya, the Division of Malaria Control is committed to ensuring that 80 percent of childhood fevers are treated with effective anti-malarial medicines within 24 hours of fever onset, but this target is largely unmet. This review aimed to document evidence on access to effective malaria treatment in Kenya, identify factors that influence access, and make recommendations on how to improve prompt access to effective malaria treatment. Since treatment-seeking patterns for malaria are similar in many settings in sub-Saharan Africa, the findings presented in this review have important lessons for other malaria endemic countries.</p> <p>Methods</p> <p>Internet searches were conducted in PUBMED (MEDLINE) and HINARI databases using specific search terms and strategies. Grey literature was obtained by soliciting reports from individual researchers working in the treatment-seeking field, from websites of major organizations involved in malaria control and from international reports.</p> <p>Results</p> <p>The review indicated that malaria treatment-seeking occurs mostly in the informal sector; that most fevers are treated, but treatment is often ineffective. Irrational drug use was identified as a problem in most studies, but determinants of this behaviour were not documented. Availability of non-recommended medicines over-the-counter and the presence of substandard anti-malarials in the market are well documented. Demand side determinants of access include perception of illness causes, severity and timing of treatment, perceptions of treatment efficacy, simplicity of regimens and ability to pay. Supply side determinants include distance to health facilities, availability of medicines, prescribing and dispensing practices and quality of medicines. Policy level factors are around the complexity and unclear messages regarding drug policy changes.</p> <p>Conclusion</p> <p>Kenya, like many other African countries, is still far from achieving the Abuja targets. The government, with support from donors, should invest adequately in mechanisms that promote access to effective treatment. Such approaches should focus on factors influencing multiple dimensions of access and will require the cooperation of all stakeholders working in malaria control.</p

    Design and descriptive epidemiology of the Infectious Diseases of East African Livestock (IDEAL) project, a longitudinal calf cohort study in western Kenya

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    BACKGROUND: There is a widely recognised lack of baseline epidemiological data on the dynamics and impacts of infectious cattle diseases in east Africa. The Infectious Diseases of East African Livestock (IDEAL) project is an epidemiological study of cattle health in western Kenya with the aim of providing baseline epidemiological data, investigating the impact of different infections on key responses such as growth, mortality and morbidity, the additive and/or multiplicative effects of co-infections, and the influence of management and genetic factors. A longitudinal cohort study of newborn calves was conducted in western Kenya between 2007-2009. Calves were randomly selected from all those reported in a 2 stage clustered sampling strategy. Calves were recruited between 3 and 7 days old. A team of veterinarians and animal health assistants carried out 5-weekly, clinical and postmortem visits. Blood and tissue samples were collected in association with all visits and screened using a range of laboratory based diagnostic methods for over 100 different pathogens or infectious exposures. RESULTS: The study followed the 548 calves over the first 51 weeks of life or until death and when they were reported clinically ill. The cohort experienced a high all cause mortality rate of 16% with at least 13% of these due to infectious diseases. Only 307 (6%) of routine visits were classified as clinical episodes, with a further 216 reported by farmers. 54% of calves reached one year without a reported clinical episode. Mortality was mainly to east coast fever, haemonchosis, and heartwater. Over 50 pathogens were detected in this population with exposure to a further 6 viruses and bacteria. CONCLUSION: The IDEAL study has demonstrated that it is possible to mount population based longitudinal animal studies. The results quantify for the first time in an animal population the high diversity of pathogens a population may have to deal with and the levels of co-infections with key pathogens such as Theileria parva. This study highlights the need to develop new systems based approaches to study pathogens in their natural settings to understand the impacts of co-infections on clinical outcomes and to develop new evidence based interventions that are relevant

    Opportunistic infections in immunosuppressed patients with juvenile idiopathic arthritis: analysis by the Pharmachild Safety Adjudication Committee

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    Background To derive a list of opportunistic infections (OI) through the analysis of the juvenile idiopathic arthritis (JIA) patients in the Pharmachild registry by an independent Safety Adjudication Committee (SAC). Methods The SAC (3 pediatric rheumatologists and 2 pediatric infectious disease specialists) elaborated and approved by consensus a provisional list of OI for use in JIA. Through a 5 step-procedure, all the severe and serious infections, classified as per MedDRA dictionary and retrieved in the Pharmachild registry, were evaluated by the SAC by answering six questions and adjudicated with the agreement of 3/5 specialists. A final evidence-based list of OI resulted by matching the adjudicated infections with the provisional list of OI. Results A total of 772 infectious events in 572 eligible patients, of which 335 serious/severe/very severe non-OI and 437 OI (any intensity/severity), according to the provisional list, were retrieved. Six hundred eighty-two of 772 (88.3%) were adjudicated as infections, of them 603/682 (88.4%) as common and 119/682 (17.4%) as OI by the SAC. Matching these 119 opportunistic events with the provisional list, 106 were confirmed by the SAC as OI, and among them infections by herpes viruses were the most frequent (68%), followed by tuberculosis (27.4%). The remaining events were divided in the groups of non-OI and possible/patient and/or pathogen-related OI. Conclusions We found a significant number of OI in JIA patients on immunosuppressive therapy. The proposed list of OI, created by consensus and validated in the Pharmachild cohort, could facilitate comparison among future pharmacovigilance studies
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