2,362 research outputs found

    Ferrets exclusively synthesize Neu5Ac and express naturally humanized influenza A virus receptors

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    Mammals express the sialic acids ​N-acetylneuraminic acid (​Neu5Ac) and ​N-glycolylneuraminic acid (​Neu5Gc) on cell surfaces, where they act as receptors for pathogens, including influenza A virus (IAV). ​Neu5Gc is synthesized from ​Neu5Ac by the enzyme cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH). In humans, this enzyme is inactive and only ​Neu5Ac is produced. Ferrets are susceptible to human-adapted IAV strains and have been the dominant animal model for IAV studies. Here we show that ferrets, like humans, do not synthesize ​Neu5Gc. Genomic analysis reveals an ancient, nine-exon deletion in the ferret CMAH gene that is shared by the Pinnipedia and Musteloidia members of the Carnivora. Interactions between two human strains of IAV with the sialyllactose receptor (sialic acid—α2,6Gal) confirm that the type of terminal sialic acid contributes significantly to IAV receptor specificity. Our results indicate that exclusive expression of ​Neu5Ac contributes to the susceptibility of ferrets to human-adapted IAV strains

    Chandra X-Ray Spectroscopy Of The Very Early O Supergiant HD 93129A: Constraints On Wind Shocks And The Mass-Loss Rate

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    We present an analysis of both the resolved X-ray emission-line profiles and the broad-band X-ray spectrum of the O-2 If* star HD 93129A, measured with the Chandra High Energy Transmission Grating Spectrometer ( HETGS). This star is among the earliest and most massive stars in the Galaxy, and provides a test of the embedded wind-shock scenario in a very dense and powerful wind. A major new result is that continuum absorption by the dense wind is the primary cause of the hardness of the observed X-ray spectrum, while intrinsically hard emission from colliding wind shocks contributes less than 10 per cent of the X-ray flux. We find results consistent with the predictions of numerical simulations of the line-driving instability, including line broadening indicating an onset radius of X-ray emission of several tenths of R-*. Helium-like forbidden-to-intercombination line ratios are consistent with this onset radius, and inconsistent with being formed in a wind-collision interface with the star\u27s closest visual companion at a distance of 100 au. The broad-band X-ray spectrum is fitted with a dominant emission temperature of just kT = 0.6 keV along with significant wind absorption. The broad-band wind absorption and the line profiles provide two independent measurements of the wind mass-loss rate:. M = 5.2(-1.5)(+1.8) x 10(-6) and 6.8(-2.2)(+2.8) x 10(-6) M-circle dot yr(-1), respectively. This is the first consistent modelling of the X-ray line-profile shapes and broad-band X-ray spectral energy distribution in a massive star, and represents a reduction of a factor of 3-4 compared to the standard H alpha mass-loss rate that assumes a smooth wind

    Gluelump Spectrum in the Bag Model

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    We explore the ordering of the lowest levels in a simple bag model of the ``gluelump'' of Michael and also discuss, again within the context of the bag model, the related problem of hybrid potentials in the limit of very small spacing between quark and anti-quark sources.Comment: 10 page

    Towards Addressing the Opportunities and Challenges of Web 2.0 for Health and Informatics

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    Objective: To provide an overview of Web 2.0 and Health 2.0, and so facilitate a widespread discussion of the nature of these concepts and their possible application within the health domain, and implications for health and biomedical informatics and for IMIA. Methods: IMIA, the International Medical Informatics Association, has established a Web 2.0 Exploratory Taskforce to bring together interested individuals from within and outside IMIA to explore the nature and potential of Web 2.0 applications. The Taskforce aims to develop background materials and sample uses of Web 2.0 applications, so as to propose specific lines of action for the IMIA Board and General Assembly. This paper provides a brief overview of Web 2.0 and related concepts, and examples of general and healthspecific Web 2.0 applications. Some examples of the issues, challenges and opportunities are introduced, to set the scene for a wider dialogue on if, how, and how best, IMIA, and the wider health and informatics communities, should use these new applications and approaches. Results and conclusions: This brief paper provides an introduction to, and overview of, the many issues involved in considering the application of Web 2.0 to health and informatics. All interested individuals and organisations are invited to use this as a starting point for engaging in wider discussion and contributing to the Taskforce and to IMIA\u27s future. Keywords IMIA, health informatics, medical informatics,IA,

    The pneumococcal alpha-glycerophosphate oxidase enhances nasopharyngeal colonization through binding to host glycoconjugates

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    Streptococcus pneumoniae (the pneumococcus) is a major human pathogen, causing a broad spectrum of diseases including otitis media, pneumonia, bacteraemia and meningitis. Here we examined the role of a potential pneumococcal meningitis vaccine antigen, alpha-glycerophosphate oxidase (SpGlpO), in nasopharyngeal colonization. We found that serotype 4 and serotype 6A strains deficient in SpGlpO have significantly reduced capacity to colonize the nasopharynx of mice, and were significantly defective in adherence to human nasopharyngeal carcinoma cells in vitro. We also demonstrate that intranasal immunization with recombinant SpGlpO significantly protects mice against subsequent nasal colonization by wild type serotype 4 and serotype 6A strains. Furthermore, we show that SpGlpO binds strongly to lacto/neolacto/ganglio host glycan structures containing the GlcNAcβ1-3Galβ disaccharide, suggesting that SpGlpO enhances colonization of the nasopharynx through its binding to host glycoconjugates. We propose that SpGlpO is a promising vaccine candidate against pneumococcal carriage, and warrants inclusion in a multi-component protein vaccine formulation that can provide robust, serotype-independent protection against all forms of pneumococcal disease

    How to increase earthquake and home fire preparedness: the fix-it intervention

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    Published, evaluated community intervention studies concerning natural hazard preparedness are rare. Most lack a rigorous methodology, thereby hampering the development of evidence-based interventions. This paper describes the rationale and methodology of a cross-cultural, longitudinal intervention study on earthquake and home fire preparedness, termed fix-it. The aim is to evaluate whether and how the intervention brings about behaviour change in the targeted communities in two coastal cities with high seismic risk: Seattle, USA and Izmir, Turkey. Participants are adult residents of these cities. The intervention group attends a 6-h workshop, which focuses on securing items in the household. The control group does not attend the workshop. All participants complete baseline and post-intervention, as well as 3- and 12-month follow-up assessments. The primary outcome measure is an observational measure of nine preparedness items for earthquake and fire in participants’ homes. This is evaluated alongside participants’ self-reports concerning their preparedness levels. Secondary outcomes are changes in levels of self-efficacy, perceived outcome, trust, corruption, empowerment, anxiety and social cohesion. Results from the first of the studies, conducted in Seattle in September 2015, indicate that while the fix-it intervention is effective, in the longer term, multi-hazard preparedness is increased by the mere act of going into people’s homes to observe their preparedness levels along with assessing self-reported preparedness and sociopsychological orientation towards natural hazards. This protocol and study aim to augment the empirical literature on natural hazard preparedness, informing national and international policy on delivery of evidence-based community interventions to promote multi-hazard preparedness in households

    Detecting solar g-modes with ASTROD

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    We present an up-to-date estimate for the prospect of using the Astrodynamical Space Test of Relativity using Optical Devices (ASTROD) for an unambiguous detection of solar g modes (f < 400 micro Hertz) through their gravitational signature. There are currently two major efforts to detect low-frequency gravitational effects, ASTROD and the Laser Interferometer Space Antenna (LISA). Using the most recent g mode surface amplitude estimates, both observational and theoretical, it is unclear whether LISA will be capable of successfully detecting these modes. The ASTROD project may be better suited for detection as its sensitivity curve is shifted towards lower frequencies with the best sensitivity occurring in the range 100-300 micro Hertz.Comment: HELAS II international conference "Helioseismology, asteroseismology and MHD connections", 20-24 August 2007, Goettingen, German

    Challenges of Early Years leadership preparation: a comparison between early and experienced Early Years practitioners in England

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    Leadership has been under-researched in the Early Years (EY) sector of primary schools in England, especially in leading change for professional development. The aim of this paper is to theorise what the leadership culture for EY practitioners looks like, and how Initial Teacher Training providers and schools are preparing practitioners for leadership. Using case studies of EY practitioners in different stages of their career in primary schools, we offer an insight into their preparedness for leadership in EY, the implication being that leadership training requires an understanding and embedding of the EY culture and context. Interviews with both sample groups allowed for deeper insight into the lived world. Interviews were also conducted with the head teachers to gain an overview of the leadership preparation they provided. The main findings suggest that newer EY practitioners are better prepared for leadership from their university training in comparison to more experienced EY practitioners
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