79 research outputs found

    A Bayesian analysis for censored Rayleigh model using a generalised hypergeometric prior

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    Based on a type II censored sample, Bayesian estimation for the scale parameter of the Rayleigh model is carried out under the assumption of the squared error loss function. A generalised hypergeometric distribution with its versatile shape of tails is introduced as a prior, and beta special cases are examined. A simulation study is carried out to investigate the sensitivity of four special cases of this beta prior family in terms of bias, frequentist coverage and mean square error and to determine their effect on robustness. Prediction bounds are derived for the lifetime of unused components using this beta prior family. A data set is used to illustrate and support some of the findings.The National Research Foundation South Africa (CPRR 13090132066 grant no. 91497).http://www.sastat.org.za/journal/informationhttp://reference.sabinet.co.za/sa_epublication/sasjam2016Statistic

    Queues with Lévy input and hysteretic control

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    We consider a (doubly) reflected Lévy process where the Lévy exponent is controlled by a hysteretic policy consisting of two stages. In each stage there is typically a different service speed, drift parameter, or arrival rate. We determine the steady-state performance, both for systems with finite and infinite capacity. Thereby, we unify and extend many existing results in the literature, focusing on the special cases of M/G/1 queues and Brownian motion. © The Author(s) 2009

    Clinical outcome of anomalous coronary artery with interarterial course in adults:Single-center experience combined with a systematic review

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    Background: Anomalous coronary artery originating from the opposite sinus of Vasalva with interarterial course (ACAOS-IAC) is associated with sudden cardiac death (SCD) in young athletes. If identified in adulthood prognosis is usually more benign, resulting in a dilemma regarding revascularization. Methods: This is a retrospective observational single-center study, including adults with ACAOS-IAC. Medical records between 2012 and 2019 were reviewed for management approach, mortality, cardiac death and coronary related adverse events. Coronary computed tomographic angiography (CCTA) were reviewed. We provide a literature review in regard to clinical outcome. Results: We identified 40 patients with ACAOS-IAC (mean age 51). Presentation was acute in 7/40 (18%). Ischemia detection with single photon emission tomography (SPECT), cardiac magnetic resonance (CMR) or dobutamine stress echocardiography were performed in 25/40 (63%) patients. Ischemia in the vascular territory of the anomaly was present in 2/25 (8%). In 39/40 (98%) patients were treated expectative. During median follow-up of 2.7 years (IQR 1.5–5.3) no cardiovascular death was observed. Mortality occurred in 1/40 (3%) and coronary related adverse events in 2/40 (5%). We identified 20 studies describing 1194 patients. Revascularization was performed in 376/1154 (32.6%) patients. Mortality stratified for clinical management was 23/431 (5.3%) in the non-revascularization versus 16/253 (6.3%) in the revascularization group during 4.0 years follow-up (weighted median). Cause of death was cardiovascular in 10/596 (1.7%) in 4.2 years (weighted median) follow up. Conclusions: Both revascularization and non-invasive management have good prognosis in adults with ACAOS-IAC during early follow up. There is need for guidelines and long-term surveillance.</p

    Pre-existing virus-specific CD8+ T-cells provide protection against pneumovirus-induced disease in mice

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    Pneumoviruses such as pneumonia virus of mice (PVM), bovine respiratory syncytial virus (bRSV) or human (h)RSV are closely related pneumoviruses that cause severe respiratory disease in their respective hosts. It is well-known that T-cell responses are essential in pneumovirus clearance, but pneumovirus-specific T-cell responses also are important mediators of severe immunopathology. In this study we determined whether memory- or pre-existing, transferred virus-specific CD8 + T-cells provide protection against PVM-induced disease. We show that during infection with a sublethal dose of PVM, both natural killer (NK) cells and CD8 + T-cells expand relatively late. Induction of CD8 + T-cell memory against a single CD8 + T-cell epitope, by dendritic cell (DC)-peptide immunization, leads to partial protection against PVM challenge and prevents Th2 differentiation of PVM-induced CD4 T-cells. In addition, adoptively transferred PVM-specific CD8 + T-cells, covering the entire PVM-specific CD8 + T-cell repertoire, provide partial protection from PVM-induced disease. From these data we infer that antigen-specific memory CD8 + T-cells offer significant protection to PVM-induced disease. Thus, CD8 + T-cells, despite being a major cause of PVM-associated pathology during primary infection, may offer promising targets of a protective pneumovirus vaccine

    Принципи управління персоналом сільськогосподарських підприємств (на прикладі Луганської області)

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    У статті проаналізовано сучасний стан сільськогосподарського виробництва в Луганській області та здійснена оцінка перспектив реформування управління персоналом на підприємствах АПК. Регресійним аналізом оцінено ступінь впливу деяких факторів на рентабельність персоналу. Рекомендується використання SWOT-аналізу для дослідження й формування раціонального управління персоналом підприємств АПК.Performed analysis of the current state of agriculture in the Luhansk region, evaluated the prospects for personnel resources reforming for the agricultural enterprises. The degree of factors influencing on profitability of personnel is appraised by the regressive analysis. SWOT-analysis is recommended for research and forming of agrarian enterprises rational management of a personnel

    Leflunomide/hydroxychloroquine combination therapy targets type I IFN-associated proteins in patients with Sjögren's syndrome that show potential to predict and monitor clinical response

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    OBJECTIVES: To assess to what extent leflunomide (LEF) and hydroxychloroquine (HCQ) therapy in patients with primary Sjögren's syndrome (RepurpSS-I) targets type I IFN-associated responses and to study the potential of several interferon associated RNA-based and protein-based biomarkers to predict and monitor treatment. METHODS: In 21 patients treated with LEF/HCQ and 8 patients treated with placebo, blood was drawn at baseline, 8, 16 and 24 weeks. IFN-signatures based on RNA expression of five IFN-associated genes were quantified in circulating mononuclear cells and in whole blood. MxA protein levels were measured in whole blood, and protein levels of CXCL10 and Galectin-9 were quantified in serum. Differences between responders and non-responders were assessed and receiver operating characteristic analysis was used to determine the capacity of baseline expression and early changes (after 8 weeks of treatment) in biomarkers to predict treatment response at the clinical endpoint. RESULTS: IFN-signatures in peripheral blood mononuclear cell and whole blood decreased after 24 weeks of LEF/HCQ treatment, however, changes in IFN signatures only poorly correlated with changes in disease activity. In contrast to baseline IFN signatures, baseline protein concentrations of galectin-9 and decreases in circulating MxA and Galectin-9 were robustly associated with clinical response. Early changes in serum Galectin-9 best predicted clinical response at 24 weeks (area under the curve 0.90). CONCLUSIONS: LEF/HCQ combination therapy targets type-I IFN-associated proteins that are associated with strongly decreased B cell hyperactivity and disease activity. IFN-associated Galectin-9 is a promising biomarker for treatment prediction and monitoring in pSS patients treated with LEF/HCQ.</p

    Predictors of Virologic Failure in HIV/AIDS Patients Treated with Highly Active Antiretroviral Therapy in Brasília, Brazil During 2002–2008

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    Little data exists concerning the efficacy of the antiretroviral therapy in the Federal District in Brazil, therefore in order to improve HIV/AIDS patients’ therapy and to pinpoint hot spots in the treatment, this research work was conducted. Of 139 HIV/AIDS patients submitted to the highly active antiretroviral therapy, 12.2% failed virologically. The significant associated factors related to unresponsiveness to the lentiviral treatment were: patients’ place of origin (OR = 3.28; IC95% = 1.0–9.73; P = 0.032) and Mycobacterium tuberculosis infection (RR = 2.90; IC95% = 1.19–7.02; P = 0.019). In the logistic regression analysis, the remaining variables in the model were: patients’ birthplace (OR = 3.28; IC95% = 1.10–9.73; P = 0.032) and tuberculosis comorbidity (OR = 3.82; IC95% = 1.19–12.22; P = 0.024). The patients enrolled in this survey had an 88.0% therapeutic success rate for the maximum period of one year of treatment, predicting that T CD4+ low values and elevated viral loads at pretreatment should be particularly considered in tuberculosis coinfection, besides the availability of new antiretroviral drugs displaying optimal activity both in viral suppression and immunological reconstitution

    Pathogenic characteristics of persistent feline enteric coronavirus infection in cats

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    Feline coronaviruses (FCoV) comprise two biotypes: feline enteric coronaviruses (FECV) and feline infectious peritonitis viruses (FIPV). FECV is associated with asymptomatic persistent enteric infections, while FIPV causes feline infectious peritonitis (FIP), a usually fatal systemic disease in domestic cats and some wild Felidae. FIPV arises from FECV by mutation. FCoV also occur in two serotypes, I and II, of which the serotype I viruses are by far the most prevalent in the field. Yet, most of our knowledge about FCoV infections relates to serotype II viruses, particularly about the FIPV, mainly because type I viruses grow poorly in cell culture. Hence, the aim of the present work was the detailed study of the epidemiologically most relevant viruses, the avirulent serotype I viruses. Kittens were inoculated oronasally with different doses of two independent FECV field strains, UCD and RM. Persistent infection could be reproducibly established. The patterns of clinical symptoms, faecal virus shedding and seroconversion were monitored for up to 10 weeks revealing subtle but reproducible differences between the two viruses. Faecal virus, i.e. genomic RNA, was detected during persistent FECV infection only in the large intestine, downstream of the appendix, and could occasionally be observed also in the blood. The implications of our results, particularly our insights into the persistently infected state, are discussed
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