Optimal control for systems with varying sampling rate

The paper addresses the aspects of control of real time systems with varying sampling rate. An example is given in which a stable continuous system is sampled at two different sampling rates. Two controllers are designed to minimize the same continuous quadratic loss function with the same weights. It is shown that although the design leads to stable controlled closed loop systems, for both discretizations, the resulting system can be unstable due to variations in sampling rate. To avoid that problem, we suggest an optimal controller design in which a bound on the cost, for all possible sampling rate variations, is computed. This results in a piecewise constant state feedback control law and guarantees stability regardless of the variations in sampling rate. The controller synthesis is cast into an LMI, which conveniently solves the synthesis problem. To illustrate the procedure, the introduction example is revised using the proposed LMI synthesis method and the stable control law is given, which is robustly stable against variations in sampling rate

What is an Appropriate Educational Response to Controversial Historical Monuments?

There are many things that can be done to educate young people about controversial topics - including historical monuments - in schools. At the same time, however, we argue that there is little warrant for optimism concerning the educational potential of classroom instruction given the interpretative frame of the state-approved history curriculum; the onerous institutional constraints under which school teachers must labour; the unusual constellation of talents history teachers must possess; the frequent absence of marginalized voices in these conversations; and finally, the not unlikely indifference - if not outright hostility - expressed by far too many members of the dominant group. For these reasons, we think it best to expand the scope of educational possibilities one is willing to consider

Low Risk of Failing Direct-Acting Antivirals in People With Human Immunodeficiency Virus/Hepatitis C Virus From Sub-Saharan Africa or Southeastern Asia: A European Cross-Sectional Study

Background: Several studies have reported suboptimal efficacy of direct-acting antivirals (DAAs) to treat hepatitis C virus (HCV) subtypes endemic to sub-Saharan Africa (SSA) and Southeastern Asia (SEA). The extent of this issue in individuals with human immunodeficiency virus (HIV)/HCV from SSA or SEA residing in Europe is unknown. Methods: We retrospectively analyzed data from several prospective European cohorts of people living with HIV. We included individuals with HIV/HCV who originated from SSA or SEA, were treated with interferon-free DAAs, and had an available HCV RNA result ≥12 weeks after the end of treatment. The primary outcome was sustained virological response at least 12 weeks after the end of treatment (SVR12). Results: Of the 3293 individuals with HIV/HCV treated with DAA and with available SVR12 data, 142 were from SSA (n = 64) and SEA (n = 78). SVR12 was achieved by 60 (94% [95% confidence interval {CI}, 86%-98%]) individuals from SSA and 76 (97% [95% CI, 92%-99%]) from SEA. The genotypes of the 6 individuals failing DAA treatment were 2, 3a, 3h, 4a, 4c, and 6j. For 2 of the 4 unsuccessfully treated individuals with available sequence data at treatment failure, NS5A resistance-associated substitutions were present (30R/93S in an individual with genotype 4c and 31M in an individual with genotype 6j). Conclusions: SVR12 rates were high in individuals with HIV/HCV residing in Europe and originating from regions where intrinsically NS5A-resistant HCV strains are endemic. HCV elimination for this population in Europe is unlikely to be hampered by suboptimal DAA efficacy. Keywords: coinfection; elimination; hepatitis C virus; human immunodeficiency viru

Screening for Hepatitis C Virus Reinfection Using a Behaviour-Based Risk Score among Men Who Have Sex with Men with HIV:Results from a Case–Control Diagnostic Validation Study

We assessed the predictive capacity of the HCV-MOSAIC risk score, originally developed for primary early HCV infection, as a screening tool for HCV reinfection in 103 men who have sex with men (MSM) with HIV using data from the MOSAIC cohort, including MSM with HIV/HCV-coinfection who became reinfected (cases, n = 27) or not (controls, n = 76) during follow-up. The overall predictive capacity of the score was assessed using the area under the receiver operating characteristic (AUROC) curve. The effects of covariates on the receiver operating characteristic (ROC) curve were assessed using parametric ROC regression. The score cut-off validated for primary early infection (≥2.0) was used, from which the sensitivity and specificity were calculated. The AUROC was 0.74 (95% confidence interval (CI) = 0.63–0.84). Group sex significantly increased the predictive capacity. Using the validated cut-off, sensitivity was 70.4% (95%CI = 49.8–86.2%) and specificity was 59.2% (95%CI: 47.3–70.4%). External validation from a cohort of 25 cases and 111 controls, all MSM with HIV, resulted in a sensitivity of 44.0% (95%CI = 24.4–65.1) and specificity of 71.2% (95%CI = 61.8–79.4). The HCV-MOSAIC risk score may be useful for identifying individuals at risk of HCV reinfection. In sexual health or HIV-care settings, this score could help guide HCV-RNA testing in MSM with a prior HCV infection.</p

Wonder, education, and human flourishing:Theoretical, empirical, and practical perspectives

The premise that underlies this volume is that there are strong interconnections between wonder, education and human flourishing. And more specifically, that wonder can make a significant difference to how well one’s education progresses and how well one’s life goes. The contributors to this volume – both senior, well-known and beginning researchers and students of wonder – variously explore aspects of these connections from philosophical, empirical, theoretical and practical perspectives. The three chapters that comprise Part I of the book are devoted to the importance of wonder for education and for human flourishing. Part II contains four chapters offering conceptual analyses of wonder and perspectives from developmental psychology and philosophy (Spinoza, Wittgenstein, philosophy of religion). The seven chapters that form Part III contain a wealth of ideas and educational strategies to promote wonder in education and teacher education. This volume not only underlines and articulates the importance of wonder in education and in life but also offers fresh perspectives, allowing us to look with renewed wonder at wonder itself

Reasons for not commencing direct-acting antiviral treatment despite unrestricted access for individuals with HIV and hepatitis C virus: a multinational, prospective cohort study.

BACKGROUND Individuals with HIV and hepatitis C virus (HCV) who remain untreated with direct-acting antivirals can contribute to HCV transmission and HCV-related mortality. We aimed to compare rates of uptake of direct-acting antivirals following unrestricted access to this treatment in high-income countries and examine factors associated with remaining untreated. METHODS This multinational, prospective cohort study used data from the International Collaboration on Hepatitis C Elimination in HIV Cohorts (InCHEHC). We analysed data from nine observational cohorts participating in the InCHEHC, including data from six high-income countries (Australia, Canada, France, the Netherlands, Spain, and Switzerland). We included individuals aged 18 years and older, with HIV and HCV (ie, HCV-RNA positive without evidence of spontaneous clearance) during unrestricted access to interferon-free direct-acting antiviral treatment in each country. We calculated the cumulative proportion of participants who remained untreated with direct-acting antivirals, with follow-up starting after the date of unrestricted access or cohort inclusion, whichever occurred most recently. Factors associated with the commencement rate of direct-acting antiviral treatment were assessed using competing-risks regression with the Fine-Gray method. FINDINGS The date of unrestricted access to direct-acting antiviral treatment for people with HIV ranged from Nov 1, 2014, in France to Nov 1, 2017, in Switzerland. We included 4552 individuals with HIV-HCV, mainly men who have sex with men (MSM; n=2156 [47%]) and people who inject or have injected drugs (n=1453 [32%]). 1365 (30%) of 4552 participants remained untreated with direct-acting antivirals. For individuals treated with direct-acting antivirals, median time from start of follow-up to treatment was 5 months (IQR 2-12). For individuals who were not treated with direct-acting antivirals, median follow-up was 22 months (8-30). Being linked to care in Australia, France, or the Netherlands, on antiretroviral therapy, having undetectable HIV RNA, and shorter duration since first positive HCV test were independently associated with higher commencement rate of direct-acting antiviral treatment. Compared with MSM, male heterosexuals and females with unknown or other routes of HIV transmission (ie, neither injection drug use nor heterosexual transmission) had lower rates of commencement. INTERPRETATION Despite unrestricted access, almost a third of individuals with HIV-HCV remained untreated with direct-acting antivirals during follow-up, with variation in commencement rate of HCV treatment between countries and key populations. Increased efforts are required to reach the remaining individuals with HIV who are HCV-viraemic to achieve HIV-HCV micro-elimination. FUNDING None

Core mutations, IL28B polymorphisms and response to peginterferon/ribavirin treatment in Swedish patients with hepatitis C virus genotype 1 infection

<p>Abstract</p> <p>Background</p> <p>Patients infected with hepatitis C virus (HCV) genotype 1 respond poorly to standard treatment with 50% or less achieving sustained virologic response. Predicting outcome is essential and could help avoid unnecessary treatment and reduce health cost. Recently, an association of amino acid substitutions in the core region and treatment outcome was observed in Japanese patients. In the present study, the impact of these mutations on response kinetics and treatment outcome was explored in Caucasian patients.</p> <p>Methods</p> <p>The core region of HCV pre-treatment samples obtained from 50 patients treated with peginterferon/ribavirin in a previous Swedish clinical trial with genotype 1 infection were sequenced. The alleles at rs12979860, a single nucleotide polymorphism (SNP), were assessed in order to identify any co-association with this strong response predictor.</p> <p>Results</p> <p>No association between treatment response and substitutions of core residue 91 was found. In contrast, substitutions of core residue 70 were observed in 6/21 (29%) non-responders, but only in one of 29 responders (p = 0.03), and were more common in subgenotype 1b (R70Q in 6 of 13 strains) than in 1a (R70P in 1 of 37 strains, p = 0.004). The rs12979860 SNP upstream of the IL28B gene was overall the strongest response predictor (p = 0.0001). Core 70 substitutions were associated with poorer response kinetics in patients carrying the CT genotype at rs12979860.</p> <p>Conclusions</p> <p>The results indicate that substitutions of core residue 70 are related to treatment response in Caucasian patients with HCV-1b infection, but are of less importance than IL28B polymorphism.</p