269 research outputs found

    Critical reflexivity in financial markets: a Hawkes process analysis

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    We model the arrival of mid-price changes in the E-Mini S&P futures contract as a self-exciting Hawkes process. Using several estimation methods, we find that the Hawkes kernel is power-law with a decay exponent close to -1.15 at short times, less than approximately 10^3 seconds, and crosses over to a second power-law regime with a larger decay exponent of approximately -1.45 for longer times scales in the range [10^3, 10^6] seconds. More importantly, we find that the Hawkes kernel integrates to unity independently of the analysed period, from 1998 to 2011. This suggests that markets are and have always been close to criticality, challenging a recent study which indicates that reflexivity (endogeneity) has increased in recent years as a result of increased automation of trading. However, we note that the scale over which market events are correlated has decreased steadily over time with the emergence of higher frequency trading.Comment: 9 pages, 6 figures. Some clarification and correction made to section II, minor alterations elsewher

    La santé des femmes au travail en France

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    Travail de service

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    International audienceL’objectif du groupe de travail composĂ© d’intervenants de l’Anact et de chercheurs Ă©tait de construire une rĂ©flexion thĂ©orique autour de la production du service ; nous avons choisi dĂ©libĂ©rĂ©ment de mixer des interrogations autour de deux configurations trĂšs diffĂ©rentes : les services rendus Ă  la personne et les services Ă  destination du grand public (comprenant les services commerciaux et les services publics). Le service doit ĂȘtre considĂ©rĂ© en lien avec le fait qu’il se situe au cƓur de rapports sociaux qui le rendent plus difficile Ă  construire, voire impossible lorsque sa construction se heurte Ă  des contradictions difficilement rĂ©ductibles ou Ă  des rapports de force dĂ©favorables. Il renvoie Ă  des mutations Ă©conomiques et du travail majeures ; le passage d’une Ă©conomie industrielle Ă  une Ă©conomie de service place le bĂ©nĂ©ficiaire — client ou encore usager — au cƓur de l’organisation et du travai

    Impact of Genotyping of Mycobacterium tuberculosis on Public Health Practice in Massachusetts

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    Massachusetts was one of seven sentinel surveillance sites in the National Tuberculosis Genotyping and Surveillance Network. From 1996 through 2000, isolates from new patients with tuberculosis (TB) underwent genotyping. We describe the impact that genotyping had on public health practice in Massachusetts and some limitations of the technique. Through genotyping, we explored the dynamics of TB outbreaks, investigated laboratory cross-contamination, and identified Mycobacterium tuberculosis strains, transmission sites, and accurate epidemiologic links. Genotyping should be used with epidemiologic follow-up to identify how resources can best be allocated to investigate genotypic findings

    Significant increase in azithromycin “resistance” and susceptibility to ceftriaxone and cefixime in Neisseria gonorrhoeae isolates in 26 European countries, 2019

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    Euro-GASP network: Claudia Eder, Sonja Pleininger, Steliana Huhlescu, Irith de Baetselier, BlaĆŸenka Hunjak, Tatjana Nemeth BlaĆŸić, Panagiota Maikanti-Charalampous, Despo Pieridou, Hana ZĂĄkouckĂĄ, Helena ĆœemličkovĂĄ, Steen Hoffmann, Susan Cowan, Rita Peetso, Jelena Viktorova, Ndeindo Ndeikoundam, Beatrice Bercot, Anu Patari Sampo, Vesa Kirjavainen, Susanne Buder, Klaus Jansen, Vivi Miriagou, Eszter Balla, MĂĄria DudĂĄs, GuĂ°rĂșn SigmundsdĂłttir, Lena Ros Asmundsdottir, Sinead Saab, Brendan Crowley, Anna Carannante, Paola Stefanelli, Gatis Pakarna, Violeta Mavcutko, Robert Cassar, Christopher Barbara, Francesca Vella, Alje Van Dam, Ineke Linde, Dominique Caugant, Hilde KlĂžvstad, Beata Mlynarczyk-Bonikowska, Maria-JosĂ© Borrego, Peter Pavlik, Irena Klavs, Tanja Kustec, Julio Vazquez, Asuncion Diaz, Raquel Abad Torreblanca, Inga Velicko, Magnus Unemo, Helen Fifer, Kate TempletonBackground: The European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP) performs annual sentinel surveillance of Neisseria gonorrhoeae susceptibility to therapeutically relevant antimicrobials across the European Union/European Economic Area (EU/EEA). We present the Euro-GASP results from 2019 (26 countries), linked to patient epidemiological data, and compared with data from previous years. Methods: Agar dilution and minimum inhibitory concentration (MIC) gradient strip methodologies were used to determine the antimicrobial susceptibility (using EUCAST clinical breakpoints, where available) of 3239 N. gonorrhoeae isolates from 26 countries across the EU/EEA. Significance of differences compared with Euro-GASP results in previous years was analysed using Z-test and the Pearson's χ2 test was used to assess significance of odds ratios for associations between patient epidemiological data and antimicrobial resistance. Results: European N. gonorrhoeae isolates collected between 2016 and 2019 displayed shifting MIC distributions for; ceftriaxone, with highly susceptible isolates increasing over time and occasional resistant isolates each year; cefixime, with highly-susceptible isolates becoming increasingly common; azithromycin, with a shift away from lower MICs towards higher MICs above the EUCAST epidemiological cut-off (ECOFF); and ciprofloxacin which is displaying a similar shift in MICs as observed for azithromycin. In 2019, two isolates displayed ceftriaxone resistance, but both isolates had MICs below the azithromycin ECOFF. Cefixime resistance (0.8%) was associated with patient sex, with resistance higher in females compared with male heterosexuals and men-who-have-sex-with-men (MSM). The number of countries reporting isolates with azithromycin MICs above the ECOFF increased from 76.9% (20/26) in 2016 to 92.3% (24/26) in 2019. Isolates with azithromycin MICs above the ECOFF (9.0%) were associated with pharyngeal infection sites. Following multivariable analysis, ciprofloxacin resistance remained associated with isolates from MSM and heterosexual males compared with females, the absence of a concurrent chlamydial infection, pharyngeal infection sites and patients ≄ 25 years of age. Conclusions: Resistance to ceftriaxone and cefixime remained uncommon in EU/EEA countries in 2019 with a significant decrease in cefixime resistance observed between 2016 and 2019. The significant increase in azithromycin "resistance" (azithromycin MICs above the ECOFF) threatens the effectiveness of the dual therapy (ceftriaxone + azithromycin), i.e., for ceftriaxone-resistant cases, currently recommended in many countries internationally and requires close monitoring.The study was funded by the European Centre for Disease Prevention and Control (Framework Contract No. ECDC/2017/004).info:eu-repo/semantics/publishedVersio

    Public health surveillance of multidrug-resistant clones of Neisseria gonorrhoeae in Europe: a genomic survey.

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    BACKGROUND: Traditional methods for molecular epidemiology of Neisseria gonorrhoeae are suboptimal. Whole-genome sequencing (WGS) offers ideal resolution to describe population dynamics and to predict and infer transmission of antimicrobial resistance, and can enhance infection control through linkage with epidemiological data. We used WGS, in conjunction with linked epidemiological and phenotypic data, to describe the gonococcal population in 20 European countries. We aimed to detail changes in phenotypic antimicrobial resistance levels (and the reasons for these changes) and strain distribution (with a focus on antimicrobial resistance strains in risk groups), and to predict antimicrobial resistance from WGS data. METHODS: We carried out an observational study, in which we sequenced isolates taken from patients with gonorrhoea from the European Gonococcal Antimicrobial Surveillance Programme in 20 countries from September to November, 2013. We also developed a web platform that we used for automated antimicrobial resistance prediction, molecular typing (N gonorrhoeae multi-antigen sequence typing [NG-MAST] and multilocus sequence typing), and phylogenetic clustering in conjunction with epidemiological and phenotypic data. FINDINGS: The multidrug-resistant NG-MAST genogroup G1407 was predominant and accounted for the most cephalosporin resistance, but the prevalence of this genogroup decreased from 248 (23%) of 1066 isolates in a previous study from 2009-10 to 174 (17%) of 1054 isolates in this survey in 2013. This genogroup previously showed an association with men who have sex with men, but changed to an association with heterosexual people (odds ratio=4·29). WGS provided substantially improved resolution and accuracy over NG-MAST and multilocus sequence typing, predicted antimicrobial resistance relatively well, and identified discrepant isolates, mixed infections or contaminants, and multidrug-resistant clades linked to risk groups. INTERPRETATION: To our knowledge, we provide the first use of joint analysis of WGS and epidemiological data in an international programme for regional surveillance of sexually transmitted infections. WGS provided enhanced understanding of the distribution of antimicrobial resistance clones, including replacement with clones that were more susceptible to antimicrobials, in several risk groups nationally and regionally. We provide a framework for genomic surveillance of gonococci through standardised sampling, use of WGS, and a shared information architecture for interpretation and dissemination by use of open access software. FUNDING: The European Centre for Disease Prevention and Control, The Centre for Genomic Pathogen Surveillance, Örebro University Hospital, and Wellcome

    Europe-wide expansion and eradication of multidrug-resistant Neisseria gonorrhoeae lineages: a genomic surveillance study

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    Centre for Genomic Pathogen Surveillance and the Euro-GASP study group: Sonja Pleininger, Alexander Indra, Irith De Baetselier, Wim Vanden Berghe, BlaĆŸenka Hunjak, Tatjana Nemeth BlaĆŸić, Panayiota Maikanti-Charalambous, Despo Pieridou, Hana ZĂĄkouckĂĄ, Helena ĆœemličkovĂĄ, Steen Hoffmann, Susan Cowan, Lasse Jessen Schwartz, Rita Peetso, Jevgenia Epstein, Jelena Viktorova, Ndeindo Ndeikoundam, Beatrice Bercot, CĂ©cile BĂ©bĂ©ar, Florence Lot, Susanne Buder, Klaus Jansen, Vivi Miriagou, Georgios Rigakos, Vasilios Raftopoulos, Eszter Balla, MĂĄria DudĂĄs, Lena RĂłs ÁsmundsdĂłttir, GuĂ°rĂșn SigmundsdĂłttir, GuĂ°rĂșn Svanborg HauksdĂłttir, Thorolfur Gudnason, Aoife Colgan, Brendan Crowley, SinĂ©ad Saab, Paola Stefanelli, Anna Carannante, Patrizia Parodi, Gatis Pakarna, Raina Nikiforova, Antra Bormane, Elina Dimina, Monique Perrin, Tamir Abdelrahman, JoĂ«l Mossong, Jean-Claude Schmit, Friedrich MĂŒhlschlegel, Christopher Barbara, Francesca Mifsud, Alje Van Dam, Birgit Van Benthem, Maartje Visser, Ineke Linde, Hilde KlĂžvstad, Dominique Caugant, Beata MƂynarczyk-Bonikowska, Jacinta Azevedo, Maria-JosĂ© Borrego, Marina Lurdes Ramos Nascimento, Peter Pavlik, Irena Klavs, Andreja Murnik, Samo Jeverica, Tanja Kustec, Julio VĂĄzquez Moreno, Asuncion Diaz, Raquel Abad, Inga Velicko, Magnus Unemo, Helen Fifer, Jill Shepherd, Lynsey PattersonBackground: Genomic surveillance using quality-assured whole-genome sequencing (WGS) together with epidemiological and antimicrobial resistance (AMR) data is essential to characterise the circulating Neisseria gonorrhoeae lineages and their association to patient groups (defined by demographic and epidemiological factors). In 2013, the European gonococcal population was characterised genomically for the first time. We describe the European gonococcal population in 2018 and identify emerging or vanishing lineages associated with AMR and epidemiological characteristics of patients, to elucidate recent changes in AMR and gonorrhoea epidemiology in Europe. Methods: We did WGS on 2375 gonococcal isolates from 2018 (mainly Sept 1-Nov 30) in 26 EU and EEA countries. Molecular typing and AMR determinants were extracted from quality-checked genomic data. Association analyses identified links between genomic lineages, AMR, and epidemiological data. Findings: Azithromycin-resistant N gonorrhoeae (8·0% [191/2375] in 2018) is rising in Europe due to the introduction or emergence and subsequent expansion of a novel N gonorrhoeae multi-antigen sequence typing (NG-MAST) genogroup, G12302 (132 [5·6%] of 2375; N gonorrhoeae sequence typing for antimicrobial resistance [NG-STAR] clonal complex [CC]168/63), carrying a mosaic mtrR promoter and mtrD sequence and found in 24 countries in 2018. CC63 was associated with pharyngeal infections in men who have sex with men. Susceptibility to ceftriaxone and cefixime is increasing, as the resistance-associated lineage, NG-MAST G1407 (51 [2·1%] of 2375), is progressively vanishing since 2009-10. Interpretation: Enhanced gonococcal AMR surveillance is imperative worldwide. WGS, linked to epidemiological and AMR data, is essential to elucidate the dynamics in gonorrhoea epidemiology and gonococcal populations as well as to predict AMR. When feasible, WGS should supplement the national and international AMR surveillance programmes to elucidate AMR changes over time. In the EU and EEA, increasing low-level azithromycin resistance could threaten the recommended ceftriaxone-azithromycin dual therapy, and an evidence-based clinical azithromycin resistance breakpoint is needed. Nevertheless, increasing ceftriaxone susceptibility, declining cefixime resistance, and absence of known resistance mutations for new treatments (zoliflodacin, gepotidacin) are promising.This study was supported by the European Centre for Disease Prevention and Control, the Centre for Genomic Pathogen Surveillance, the Li Ka Shing Foundation (Big Data Institute, University of Oxford), the Wellcome Genome Campus, the Foundation for Medical Research at Örebro University Hospital, and grants from Wellcome (098051 and 099202). LSB was funded by Conselleria de Sanitat Universal i Salut PĂșblica, Generalitat Valenciana (Plan GenT CDEI-06/20-B), Valencia, Spain, and Ministry of Science, Innovation and Universities (PID2020–120113RA-I00), Spain, at the time of analysing and writing this manuscript.info:eu-repo/semantics/publishedVersio
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