9 research outputs found

    Global properties of Stochastic Loewner evolution driven by Levy processes

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    Standard Schramm-Loewner evolution (SLE) is driven by a continuous Brownian motion which then produces a trace, a continuous fractal curve connecting the singular points of the motion. If jumps are added to the driving function, the trace branches. In a recent publication [1] we introduced a generalized SLE driven by a superposition of a Brownian motion and a fractal set of jumps (technically a stable L\'evy process). We then discussed the small-scale properties of the resulting L\'evy-SLE growth process. Here we discuss the same model, but focus on the global scaling behavior which ensues as time goes to infinity. This limiting behavior is independent of the Brownian forcing and depends upon only a single parameter, α\alpha, which defines the shape of the stable L\'evy distribution. We learn about this behavior by studying a Fokker-Planck equation which gives the probability distribution for endpoints of the trace as a function of time. As in the short-time case previously studied, we observe that the properties of this growth process change qualitatively and singularly at α=1\alpha =1. We show both analytically and numerically that the growth continues indefinitely in the vertical direction for α>1\alpha > 1, goes as logt\log t for α=1\alpha = 1, and saturates for α<1\alpha< 1. The probability density has two different scales corresponding to directions along and perpendicular to the boundary. In the former case, the characteristic scale is X(t)t1/αX(t) \sim t^{1/\alpha}. In the latter case the scale is Y(t)A+Bt11/αY(t) \sim A + B t^{1-1/\alpha} for α1\alpha \neq 1, and Y(t)lntY(t) \sim \ln t for α=1\alpha = 1. Scaling functions for the probability density are given for various limiting cases.Comment: Published versio

    Long-term treatment with atazanavir (ATV) in real life in Belgium: a retrospective observational cohort of 2264 HIV patients.

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    Objectives This 5-year follow-up study aimed to assess clinical outcomes of HIV-1 infected adults treated with atazanavir (ATV) in clinical practice in Belgium, to describe patient profiles and characteristics, as well as treatment safety. Methods A multicenter, non-interventional, non-comparative, retrospective cohort study was performed in HIV-1 positive adult patients treated with ATV between 2006 and 2012. Data were collected from 8 AIDS reference centers' databases. All analyses were on-treatment. Sub-analyses were carried out in unboosted ATV treated patients and in females. The primary endpoint was defined as the time-to-treatment-discontinuation. Furthermore, virological suppression, immunological response, time to loss of virological response, reasons for ATV initiation, and discontinuation were also assessed. Results 2264 ARV-naive and ARV-experienced patients (median age: 41 years) were included. Females and non-Caucasians were broadly represented (40 and 45%, respectively). The probability to remain on treatment was 0.78 (CI: 0.76; 0.78) for the first and 0.69 (CI: 0.66; 0.71) for the second year and was similar between males and females. Overall, 771 patients (34.1%) discontinued ATV over time, the median (Q1-Q3) time to discontinuation being 0.8 (0.3-1.5) year. In unboosted ATV-treated patients, results were comparable to the overall ATV population, except for a higher rate of discontinuation-over-time (45.1%). Conclusions Clinical and safety data from this 5 year-cohort study show that the vast majority of patients remained on ATV treatment for the first and second years, overall as well as patients treated with unboosted ATV and females.info:eu-repo/semantics/publishe

    A highly virulent variant of HIV-1 circulating in the Netherlands.

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    We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log &lt;sub&gt;10&lt;/sub&gt; increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence

    A highly virulent variant of HIV-1 circulating in the Netherlands

    No full text
    We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log10 increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence

    HIV testing history and access to treatment among migrants living with HIV in Europe

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    Introduction: Migrants are overrepresented in the European HIV epidemic. We aimed to understand the barriers and facilitators to HIV testing and current treatment and healthcare needs of migrants living with HIV in Europe. Methods: A cross-sectional study was conducted in 57 HIV clinics in nine countries (Belgium, Germany, Greece, Italy, The Netherlands, Portugal, Spain, Switzerland and United Kingdom), July 2013 to July 2015. HIV-positive patients were eligible for inclusion if they were as follows: 18 years or older; foreign-born residents and diagnosed within five years of recruitment. Questionnaires were completed electronically in one of 15 languages and linked to clinical records. Primary outcomes were access to primary care and previous negative HIV test. Data were analysed using random effects logistic regression. Outcomes of interest are presented for women, heterosexual men and gay/bisexual men. Results: A total of 2093 respondents (658 women, 446 heterosexual men and 989 gay/bisexual men) were included. The prevalence of a previous negative HIV test was 46.7%, 43.4% and 82.0% for women, heterosexual and gay/bisexual men respectively. In multivariable analysis previous testing was positively associated with: receipt of post-migration antenatal care among women, permanent residency among heterosexual men and identifying as gay rather than bisexual among gay/bisexual men. Access to primary care was found to be high (&gt;83%) in all groups and was strongly associated with country of residence. Late diagnosis was common for women and heterosexual men (60.8% and 67.1%, respectively) despite utilization of health services prior to diagnosis. Across all groups almost three-quarters of people on antiretrovirals had an HIV viral load &lt;50 copies/mL. Conclusions: Migrants access healthcare in Europe and while many migrants had previously tested for HIV, that they went on to test positive at a later date suggests that opportunities for HIV prevention are being missed. Expansion of testing beyond sexual health and antenatal settings is still required and testing opportunities should be linked with combination prevention measures such as access to PrEP and treatment as prevention. © 2018 The Authors. Journal of the International AIDS Society published by John Wiley &amp; sons Ltd on behalf of the International AIDS Society

    High levels of postmigration HIV acquisition within nine European countries

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    Objective: We aimed to estimate the proportion of postmigration HIV acquisition among HIV-positive migrants in Europe. Design: To reach HIV-positive migrants, we designed a cross-sectional study performed in HIV clinics. Methods: The study was conducted from July 2013 to July 2015 in 57 clinics (nine European countries), targeting individuals over 18 years diagnosed in the preceding 5 years and born abroad. Electronic questionnaires supplemented with clinical data were completed in any of 15 languages. Postmigration HIV acquisition was estimated through Bayesian approaches combining extensive information on migration and patients&apos; characteristics. CD4+ cell counts and HIV-RNA trajectories from seroconversion were estimated by bivariate linear mixed models fitted to natural history data. Postmigration acquisition risk factors were investigated with weighted logistic regression. Results: Of 2009 participants, 46% were MSM and a third originated from sub-Saharan Africa and Latin America &amp;amp; Caribbean, respectively. Median time in host countries was 8 years. Postmigration HIV acquisition was 63% (95% confidence interval: 57-67%); 72% among MSM, 58 and 51% in heterosexual men and women, respectively. Postmigration HIV acquisition was 71% for Latin America and Caribbean migrants and 45% for people from sub-Saharan Africa. Factors associated with postmigration HIV acquisition among heterosexual women and MSM were age at migration, length of stay in host country and HIV diagnosis year and among heterosexual men, length of stay in host country and HIV diagnosis year. Conclusion: A substantial proportion of HIV-positive migrants living in Europe acquired HIV postmigration. This has important implications for European public health policies. Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved
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