37 research outputs found

    Individual variation in susceptibility or exposure to SARS-CoV-2 lowers the herd immunity threshold

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    Funding Information: We thank Jorge Carneiro, Ben Cooper, José Ferreira Machado, Kate Langwig, Robert MacKay, Paul McKeigue, Antonio Montalbán, Joe Schoneman, Laurette Tuckerman and Simon Wood for valuable discussions throughout this study. At the University of Strathclyde, Matthew Burns, Zhichun Jiang, Naithan McNeil, Lauren Schofield and Aidan West conducted their final year BSc projects on Communicating Mathematics and Statistics, supervised by M.G.M.G., on topics related to this study while this paper was being written. This has contributed clarity to our presentation. The models presented here were first submitted to medRxiv on 27 April 2020 and posted soon after. Applications to the COVID-19 pandemic and subsequent updates followed. We are grateful to the preprint server for making our work available to interested readers in real time. M.U.F. received funding from Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil. Funding Information: We thank Jorge Carneiro, Ben Cooper, Jos? Ferreira Machado, Kate Langwig, Robert MacKay, Paul McKeigue, Antonio Montalb?n, Joe Schoneman, Laurette Tuckerman and Simon Wood for valuable discussions throughout this study. At the University of Strathclyde, Matthew Burns, Zhichun Jiang, Naithan McNeil, Lauren Schofield and Aidan West conducted their final year BSc projects on Communicating Mathematics and Statistics, supervised by M.G.M.G. on topics related to this study while this paper was being written. This has contributed clarity to our presentation. The models presented here were first submitted to medRxiv on 27 April 2020 and posted soon after. Applications to the COVID-19 pandemic and subsequent updates followed. We are grateful to the preprint server for making our work available to interested readers in real time. M.U.F. received funding from Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico, Brazil. Publisher Copyright: © 2022 Elsevier LtdIndividual variation in susceptibility and exposure is subject to selection by natural infection, accelerating the acquisition of immunity, and reducing herd immunity thresholds and epidemic final sizes. This is a manifestation of a wider population phenomenon known as “frailty variation”. Despite theoretical understanding, public health policies continue to be guided by mathematical models that leave out considerable variation and as a result inflate projected disease burdens and overestimate the impact of interventions. Here we focus on trajectories of the coronavirus disease (COVID-19) pandemic in England and Scotland until November 2021. We fit models to series of daily deaths and infer relevant epidemiological parameters, including coefficients of variation and effects of non-pharmaceutical interventions which we find in agreement with independent empirical estimates based on contact surveys. Our estimates are robust to whether the analysed data series encompass one or two pandemic waves and enable projections compatible with subsequent dynamics. We conclude that vaccination programmes may have contributed modestly to the acquisition of herd immunity in populations with high levels of pre-existing naturally acquired immunity, while being crucial to protect vulnerable individuals from severe outcomes as the virus becomes endemic.publishersversionpublishe

    Individual variation in susceptibility or exposure to SARS-CoV-2 lowers the herd immunity threshold

    Get PDF
    Individual variation in susceptibility and exposure is subject to selection by natural infection, accelerating the acquisition of immunity, and reducing herd immunity thresholds and epidemic final sizes. This is a manifestation of a wider population phenomenon known as "frailty variation". Despite theoretical understanding, public health policies continue to be guided by mathematical models that leave out considerable variation and as a result inflate projected disease burdens and overestimate the impact of interventions. Here we focus on trajectories of the coronavirus disease (COVID-19) pandemic in England and Scotland until November 2021. We fit models to series of daily deaths and infer relevant epidemiological parameters, including coefficients of variation and effects of non-pharmaceutical interventions which we find in agreement with independent empirical estimates based on contact surveys. Our estimates are robust to whether the analysed data series encompass one or two pandemic waves and enable projections compatible with subsequent dynamics. We conclude that vaccination programmes may have contributed modestly to the acquisition of herd immunity in populations with high levels of pre-existing naturally acquired immunity, while being crucial to protect vulnerable individuals from severe outcomes as the virus becomes endemic

    Bird-termite interactions in Brazil: A review with perspectives for future studies

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    Brazilian coffee genome project: an EST-based genomic resource

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    In Situ Observation of Epitaxial Growth during Evaporative Simultaneous Crystallization from Aqueous Electrolytes in Droplets

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    In this study, crystallization phenomena were investigated by real-time in situ observation of seeded droplets under evaporation using a self-developed hot-stage platform. Ternary solutions at eutonic conditions at 25 °C were investigated for the following systems: NaCl–KCl–H2O, NaCl–CaSO4–H2O, and NaCl–Na2SO4–H2O. Evidence of epitaxial growth was found for aqueous NaCl–KCl and aqueous NaCl–Na2SO4. Sodium chloride nucleated and grew epitaxially upon the other substrates in a larger proportion compared with the inverse. This observation could be related to the higher solubility, and consequently higher residual supersaturation of NaCl regarding the other components. Hopper-like NaCl crystals developed in almost all systems. The results may help devise strategies to control particle morphologies and purity in industrial crystallization from complex systems.QC 20211018</p

    Therapeutic monoclonal antibodies in ophthalmology

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    Monoclonal antibodies (mAbs) can be used therapeutically by binding to molecular targets with high specificity. Therefore, they have excellent therapeutic applications in ophthalmology. This manuscript presents four aspects of the therapeutic use of mAbs in ophthalmology: the scientific rationale, the unique characteristics of selected mAbs, the current state-of-the-art application, and relevant therapeutic mAbs for future applications in ophthalmology. We identified in the literature various single-agent therapies that inhibit the following targets: tumor necrosis factor (TNF), epithelial growth factor receptor, vascular endothelial growth factor (VEGF) receptor, basic fibroblast growth factor receptor, platelet-derived growth factor, and cluster of differentiation antigens. the roles of all biochemical targets in ocular diseases were evaluated. Current and future mAbs against various cytokines were assessed for the treatment of ocular diseases. the medical literature showed the clinical benefits of mAbs for treating angiogenic and inflammatory ocular diseases. Two anti-VEGF mAbs, bevacizumab and ranibizumab, and three anti-TNF agents, infliximab, etanercept, and adalimumab, control Ocular neovascularization and intraocular inflammation. Other mAbs such as rituximab, daclizumab, efalizumab, and alemtuzumab showed positive results in animal and early clinical studies and may represent useful adjuvant therapies for ocular lymphoma or ocular inflammation. Ranibizumab is the only FDA-approved therapy; for other mAbs the so-called off-label application remains the standard. Intravenous administration of mAbs has demonstrated acceptable toxicity profiles, while intraocular injection may decrease the chances of systemic complications and increase the amount of drug available to the retina and choroid. in conclusion, effective clinical use of mAbs in ophthalmology is more commonly seen in the field of angiogenic vitreoretinal and autoimmune inflammatory diseases. the challenge for the future is combining biologic therapies to improve the quality and duration of responses while diminishing side effects. the role of mAbs within ophthalmic treatments will be defined according to future clinical experience and the results of randomized clinical trials. (C) 2008 Elsevier B.V. All rights reserved.Universidade Federal de São Paulo, Dept Ophthalmol, Vis Inst, São Paulo, BrazilUniversidade Federal de São Paulo, Div Rheumatol, São Paulo, BrazilUniv Fed Santa Catarina, Dept Immunol, Florianopolis, SC, BrazilUniversidade Federal de São Paulo, Dept Ophthalmol, Vis Inst, São Paulo, BrazilUniversidade Federal de São Paulo, Div Rheumatol, São Paulo, BrazilWeb of Scienc

    ZnWO4 nanocrystals: synthesis, morphology, photoluminescence and photocatalytic properties

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    The present joint experimental and theoretical work provides in-depth understanding on the morphology and structural, electronic, and optical properties of ZnWO4 nanocrystals. Monoclinic ZnWO4 nanocrystals were prepared at three different temperatures (140, 150, and 160 1C) by a microwave hydrothermal method. Then, the samples were investigated by X-ray diffraction with Rietveld refinement analysis, fieldemission scanning electron microscopy, transmission electronic microscopy, micro-Raman and Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and photoluminescence measurements. First-principles theoretical calculations within the framework of density functional theory were employed to provide information at the atomic level. The band structure diagram, density of states, Raman and infrared spectra were calculated to understand the effect of structural order–disorder on the properties of ZnWO4. The effects of the synthesis temperature on the above properties were rationalized. The band structure revealed direct allowed transitions between the VB and CB and the experimental results in the ultraviolet-visible region were consistent with the theoretical results. Moreover, the surface calculations allowed the association of the surface energy stabilization with the temperature used in the synthesis of the ZnWO4 nanocrystals. The photoluminescence properties of the ZnWO4 nanocrystals prepared at 140, 150, and 160 1C were attributed to oxygen vacancies in the [WO6] and [ZnO6] clusters, causing a red shift of the spectra. The ZnWO4 nanocrystals obtained at 160 1C exhibited excellent photodegradation of Rhodamine under ultraviolet light irradiation, which was found to be related to the surface energy and the types of clusters formed on the surface of the catalyst
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