906 research outputs found

    COVID-19 mortality among people with diagnosed HIV compared to those without during the first wave of the COVID-19 pandemic in England

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    Objectives: We describe COVID-19 mortality among people with and without HIV during the first wave of the pandemic in England. / Methods: National surveillance data on adults (aged ≥ 15 years) with diagnosed HIV resident in England were linked to national COVID-19 mortality surveillance data (2 March 2020–16 June 2020); HIV clinicians verified linked cases and provided information on the circumstances of death. We present COVID-19 mortality rates by HIV status, using negative binomial regression to assess the association between HIV and mortality, adjusting for gender, age and ethnicity. / Results: Overall, 99 people with HIV, including 61 of black ethnicity, died of/with COVID-19 (107/100 000) compared with 49 483 people without HIV (109/100 000). Compared to people without HIV, higher COVID-19 mortality rates were observed in people with HIV of black (188 vs. 122/100 000) and Asian (131 vs. 77.0/100 000) ethnicity, and in both younger (15–59 years: 58.3 vs. 10.2/100 000) and older (≥ 60 years: 434 vs. 355/100 000) people. After adjustment for demographic factors, people with HIV had a higher COVID-19 mortality risk than those without (2.18; 95% CI: 1.76–2.70). Most people with HIV who died of/with COVID-19 had suppressed HIV viraemia (91%) and at least one comorbidity reported to be associated with poor COVID-19 outcomes (87%). / Conclusions: In the first wave of the pandemic in England, COVID-19 mortality among people with HIV was low, but was higher than in those without HIV, after controlling for demographic factors. This supports the strategy of prioritizing COVID-19 vaccination for people with HIV and strongly encouraging its uptake, especially in those of black and Asian ethnicity

    Loop Quantum Gravity a la Aharonov-Bohm

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    The state space of Loop Quantum Gravity admits a decomposition into orthogonal subspaces associated to diffeomorphism equivalence classes of spin-network graphs. In this paper I investigate the possibility of obtaining this state space from the quantization of a topological field theory with many degrees of freedom. The starting point is a 3-manifold with a network of defect-lines. A locally-flat connection on this manifold can have non-trivial holonomy around non-contractible loops. This is in fact the mathematical origin of the Aharonov-Bohm effect. I quantize this theory using standard field theoretical methods. The functional integral defining the scalar product is shown to reduce to a finite dimensional integral over moduli space. A non-trivial measure given by the Faddeev-Popov determinant is derived. I argue that the scalar product obtained coincides with the one used in Loop Quantum Gravity. I provide an explicit derivation in the case of a single defect-line, corresponding to a single loop in Loop Quantum Gravity. Moreover, I discuss the relation with spin-networks as used in the context of spin foam models.Comment: 19 pages, 1 figure; v2: corrected typos, section 4 expanded

    Взаємний зв'язок властивостей і структури плівкових чутливих елементів сенсорів магнітного поля

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    Дисертацію присвячено комплексним експериментальним дослідженням особливостей структурно-фазового стану та магнітних і магніторезистивних властивостей багатошарових плівкових систем на основі Co і Cu, Co і Cr, Fe і Cr та Fe і Cu як можливих матеріалів чутливих елементів сенсорів різного призначення. У роботі встановлено взаємозв’язок між товщиною магнітних шарів і немагнітних прошарків, орієнтацією зразка у зовнішньому магнітному полі, температурою термообробки та магнітними, магніторезистивними і магнітооптичними властивостями багатошарових плівкових систем із можливим спін-залежним розсіюванням електронів. Визначені величини магнітоопору, коерцитивної сили, коефіцієнта прямокутності й чутливості плівкової системи до магнітного поля досліджуваних плівкових систем як приладових структур для формування первинних перетворювачів. Установлена кореляція між структурно-фазовим станом, магнітними та магнітооптичними властивостями тришарових плівкових систем з різним типом розчинності компонент як функціональних елементів датчиків. Запропонована схематична конструкція АМР-датчика магнітного поля для тришарових плівкових систем із спін-залежним розсіюванням електронів. У результаті проведених досліджень впливу геометрії вимірювання, температури термообробки та загальної концентрації феромагнітної компоненти в системі на магнітні й магніторезистивні властивості визначені можливі області застосування плівкових систем на основі Co і Cu або Cr та Fe і Cu або Cr.Диссертация посвящена комплексным экспериментальным исследованиям особенностей структурно-фазового состояния, магнитных магниторезистивных свойств многослойных пленочных систем на основе Co и Cu, Co и Cr, Fe и Cr и Fe и Cu в качестве возможных материалов чувствительных элементов сенсоров различного назначения. В работе установлена взаимосвязь между толщиной магнитных слоев и немагнитных прослоек, ориентацией образца во внешнем магнитном поле, температурой термообработки и магнитными, магниторезистивными и магнитооптическими свойствами многослойных пленочных систем с возможным спин-зависимым рассеянием электронов. При исследовании магнитных свойств пленочных систем на основе Fe, Co, Cu или Cr получено, что для пленочных систем на основе Fe и Cu в форме кривых гистерезиса наблюдается определенный перегиб, свидетельствующий о послойном перемагничивании слоев Fe, в то время как для систем на основе Fe и Cr петля гистерезиса имеет форму, подобную однослойным пленкам Fe, что говорит о преобладании ферромагнитной связи в системе. В пленочных структурах на основе Co и Cr или Cu магнитные свойства системы главным образом определяются состоянием слоев Со, поэтому форма кривых гистерезиса для обеих систем схожа с формой кривых для однослойных пленок Со, а небольшие значения коэрцитивной силы свидетельствуют о реализации ферромагнитной связи в системе. Все четыре системы характеризуются достаточно высоким значением коэффициента прямоугольности, которое при смене ориентации образца от 0 до 90° несколько уменьшается для систем Fe/Cu/Fe и Fe/Cr/Fe и, наоборот, растет в системах на основе Co и Cr. Определены величины магнитосопротивления, коэрцитивной силы, коэффициента прямоугольности и чувствительности пленочной системы к магнитному полю исследуемых пленочных систем как приборных структур для формирования первичных преобразователей. Установлена корреляция между структурно-фазовым состоянием, магнитными и магнитооптическими свойствами трехслойных пленочных систем с разным типом растворимости компонент в качестве функциональных элементов датчиков. Предложена схематическая конструкция АМР-датчика магнитного поля для трехслойных пленочных систем со спин-зависимым рассеянием электронов. В результате проведенных исследований влияния геометрии измерения, температуры термообработки и общей концентрации ферромагнитной компоненты в системе на магниторезистивные свойства определены возможные области применения пленочных систем на основе Co и Cu или Cr и Fe и Cu или Cr.The thesіs іs dedіcаted to the complex experіmentаl reseаrch between the structurаl-phаse stаte, magnetic and magnetoresistance propertіes of multіlаyer fіlm systems bаsed on the Co аnd Cu, Co аnd Cr, Fe аnd Cr, аnd Fe аnd Cu, аs the potential mаterіаls for sensіtіve elements of sensors for dіfferent purposes. Іn thіs thesis wаs found the correlаtіon between the thіckness of the mаgnetіc аnd nonmаgnetіc lаyers, the orіentаtіon of the sаmple іn аn externаl mаgnetіc fіeld, temperаture of heаt treаtment аnd mаgnetіc, mаgnetoresіstіve аnd mаgneto-optіcаl propertіes іn multіlаyer fіlm systems wіth possіble spіn-dependent scаtterіng of electrons. The vаlues of mаgnetoresіstаnce, coercіvіty, squаreness fаctor аnd sensіtіvіty of fіlm system to a mаgnetіc fіeld in the studіed fіlm systems аs devіce structures for the formаtіon of prіmаry converters were defined. The correlаtіon between the structurаl-phаse stаte, mаgnetіc аnd mаgneto-optіcаl propertіes of three-lаyer fіlm systems wіth dіfferent types of component solubіlіty аs functіonаl elements sensors was established. The schemаtіc sturucture of АMR sensor for three-lаyer fіlm systems wіth spіn-dependent scаtterіng of electrons was purposed. The possіble аreаs of аpplіcаtіons wаs іdentіfіed on the bаsіs of studіes of the effect of geometry meаsurement temperаture heаt treаtment аnd the totаl concentrаtіon of ferromаgnetіc components іn the system on the magnetic and mаgnetoresіstіve propertіes of fіlm-systems bаsed on Co аnd Cu, or Cr аnd Fe, аnd Cu or Cr

    Nutrition, environment and cardiovascular health (NESCAV): protocol of an inter-regional cross-sectional study

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    BACKGROUND: Despite the remarkable technological progress in health care and treatment, cardiovascular disease remains the leading cause of premature death, prolonged hospitalization and disability in most European countries. In the population of the Greater Region (Grand-Duchy of Luxembourg, Wallonia in Belgium, and Lorraine in France), the prevalence of cardiovascular risk factors and disease is among the highest in Europe, warranting the need for a better understanding of factors contributing to this pattern. In this context, the cross-border "Nutrition, Environment and Cardiovascular Health-NESCAV" project is initiated by an inter-regional multi-disciplinary consortium and supported by the INTERREG IV A program "Greater Region", 2007-2013, to fight synergically and harmoniously against this major public health problem. METHODS/DESIGN: The objectives of the three-year planned project are to assess, in a representative sample of 3000 randomly selected individuals living at the Greater Region, 1) the cardiovascular health and risk profile, 2) the association between the dietary habits and the cardiovascular risk, 3) the association of occupational and environmental pollution markers with the cardiovascular risk, 4) the knowledge, awareness and level of control of cardiovascular risk factors, 5) the potential gaps in the current primary prevention, and finally, to address evidence-based recommendations enabling the development of inter-regional guidance to help policy-makers and health care workers for the prevention of cardiovascular disease. DISCUSSION: The findings will provide tools that may enable the Greater Region's decision-makers and health professionals to implement targeted and cost-effective prevention strategies

    Transmural Ultrasound-based Visualization of Patterns of Action Potential Wave Propagation in Cardiac Tissue

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    The pattern of action potential propagation during various tachyarrhythmias is strongly suspected to be composed of multiple re-entrant waves, but has never been imaged in detail deep within myocardial tissue. An understanding of the nature and dynamics of these waves is important in the development of appropriate electrical or pharmacological treatments for these pathological conditions. We propose a new imaging modality that uses ultrasound to visualize the patterns of propagation of these waves through the mechanical deformations they induce. The new method would have the distinct advantage of being able to visualize these waves deep within cardiac tissue. In this article, we describe one step that would be necessary in this imaging process—the conversion of these deformations into the action potential induced active stresses that produced them. We demonstrate that, because the active stress induced by an action potential is, to a good approximation, only nonzero along the local fiber direction, the problem in our case is actually overdetermined, allowing us to obtain a complete solution. Use of two- rather than three-dimensional displacement data, noise in these displacements, and/or errors in the measurements of the fiber orientations all produce substantial but acceptable errors in the solution. We conclude that the reconstruction of action potential-induced active stress from the deformation it causes appears possible, and that, therefore, the path is open to the development of the new imaging modality

    Draft Genome Sequencing of Giardia intestinalis Assemblage B Isolate GS: Is Human Giardiasis Caused by Two Different Species?

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    Giardia intestinalis is a major cause of diarrheal disease worldwide and two major Giardia genotypes, assemblages A and B, infect humans. The genome of assemblage A parasite WB was recently sequenced, and the structurally compact 11.7 Mbp genome contains simplified basic cellular machineries and metabolism. We here performed 454 sequencing to 16× coverage of the assemblage B isolate GS, the only Giardia isolate successfully used to experimentally infect animals and humans. The two genomes show 77% nucleotide and 78% amino-acid identity in protein coding regions. Comparative analysis identified 28 unique GS and 3 unique WB protein coding genes, and the variable surface protein (VSP) repertoires of the two isolates are completely different. The promoters of several enzymes involved in the synthesis of the cyst-wall lack binding sites for encystation-specific transcription factors in GS. Several synteny-breaks were detected and verified. The tetraploid GS genome shows higher levels of overall allelic sequence polymorphism (0.5 versus <0.01% in WB). The genomic differences between WB and GS may explain some of the observed biological and clinical differences between the two isolates, and it suggests that assemblage A and B Giardia can be two different species

    Search for rare quark-annihilation decays, B --> Ds(*) Phi

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    We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and u-bar quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions BF(B- --> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results are consistent with Standard Model expectations.Comment: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid Communications
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