4,546 research outputs found

    Algebraic properties of Gardner's deformations for integrable systems

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    An algebraic definition of Gardner's deformations for completely integrable bi-Hamiltonian evolutionary systems is formulated. The proposed approach extends the class of deformable equations and yields new integrable evolutionary and hyperbolic Liouville-type systems. An exactly solvable two-component extension of the Liouville equation is found.Comment: Proc. conf. "Nonlinear Physics: Theory and Experiment IV" (Gallipoli, 2006); Theor. Math. Phys. (2007) 151:3/152:1-2, 16p. (to appear

    Effect of char on the combustion process of multicomponent bio-fuel

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    Combustion of pyrolysis oil has attracted many attention in recent years as a renewable and environmental friendly fuel. However, pyrolysis oil as an multi-component fuel has some differences compared to conventional fossil fuels. One of the main differences is the formation of solid char in the droplet during evaporation. The goal of this work is to study the effect of the solid char on the combustion characteristics of multi-component fuel. An Euler-Lagrange model of three phase gas/liquid/solid combustion is developed to study the detailed information about every phenomena in the process such as: heat, mass and momentum transfer between droplet and gas phase, droplet evaporation, homogeneous and heterogeneous reactions. The results indicate that the presence of the solid char and consequently its combustion elongates significantly the combustion region in a typical spray injection chamber/burner. Moreover, the gas phase reaches higher temperatures as a result of char combustion that creates more heat by heterogeneous oxidation as a kind of afterburner

    Particles as probes for complex plasmas in front of biased surfaces

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    An interesting aspect in the research of complex (dusty) plasmas is the experimental study of the interaction of micro-particles with the surrounding plasma for diagnostic purposes. Local electric fields can be determined from the behaviour of particles in the plasma, e.g. particles may serve as electrostatic probes. Since in many cases of applications in plasma technology it is of great interest to describe the electric field conditions in front of floating or biased surfaces, the confinement and behaviour of test particles is studied in front of floating walls inserted into a plasma as well as in front of additionally biased surfaces. For the latter case, the behaviour of particles in front of an adaptive electrode, which allows for an efficient confinement and manipulation of the grains, has been experimentally studied in dependence on the discharge parameters and on different bias conditions of the electrode. The effect of the partially biased surface (dc, rf) on the charged micro-particles has been investigated by particle falling experiments. In addition to the experiments we also investigate the particle behaviour numerically by molecular dynamics, in combination with a fluid and particle-in-cell description of the plasma.Comment: 39 pages, 16 figures, submitted to New J. Phy

    EMPOWERing older people and their communities to manage their own CARE (EMPOWERCARE): Evaluation study of a social innovation initiative across four European countries

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    This paper outlines the evaluation strategy of the EMPOWERCARE, an EU Interreg 2 Seas funded social innovation project, which involves a partnership of local authorities, universities and non-governmental organisations from four European countries: Belgium, France, the Netherlands and the United Kingdom. Partners are working in collaboration with local people aged 65+, and those aged 50+ with at least one chronic condition, to respond to current gaps in the care of older people. The project aims specifically to contribute to person-centred care and technology knowledge transfer whilst reducing isolation, loneliness and increasing solidarity amongst older people and their communities. During the project, partners are jointly developing a strategy for implementing good-practice models, a workforce transformation approach via shared training and a technology blueprint with emphasis on caring digital technologies to address the rising demand for health and social care services for older people. The project addresses this challenge by drawing on community assets, involving older people in decisions about their own health and wellbeing, enabling them to keep healthier and in their own homes and communities safely for longer. The project’s evaluation aims to measure the impact of the EMPOWERCARE initiative across 7 pilot sites in the 4 participating countries. Given the Covid-19 pandemic, the evaluation design has been developed with a view to being agile and able to respond to complex and shifting situations, and especially so in terms of what and how data are collected. A realist synthesis approach (Pawson & Tilley, 2004) guides the evaluation within a descriptive case study design (Yin 2003) to identify and contextualise the project strategies that are influential within and across the 7 different case study sites. The evaluation uses multiple interdisciplinary methods, such as surveys, Photovoice and Social Return on Investment, to capture a range of perspectives across three timepoints, baseline (T0), mid-point (T1) and end-point (T2). Online surveys are conducted with both end-users and the workforce in all pilot sites at T0 and T2. At T1, end-users are actively involved in creating visual data through Photovoice to capture their lived experiences with local initiatives in pilot sites. Visual data are going to be displayed at pilot site exhibitions targeted to key local stakeholders and members of the workforce. Focus groups will be conducted with all participants reflecting on the visual data exhibition to explore insights about the initiative from current and future perspectives. This aspect is informed by a Social Return on Investment approach. The sequential data collection of multiple sources and longitudinal study design identify patterns of change and impact. The evaluation design will deliver a theory-driven rich explanation of what works about EMPOWERCARE and for whom, why, how and in what circumstances it works. The analysis of the evaluation findings will contribute to a more empowered person-centred approach, with more inclusive and caring digital health solutions that will allow policy makers to develop localised, efficient and social-value driven services to meet the rising needs of older people in the European regions

    Relations among neutrino observables in the light of a large theta_13 angle

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    The recent T2K and MINOS indications for a "large" theta_13 neutrino mixing angle can be accommodated in principle by an infinite number of Yukawa flavour structures in the seesaw model. Without considering any explicit flavour symmetry, there is an instructive exercise one can do: to determine the simplest flavour structures which can account for the data with a minimum number of parameters, simply assuming these parameters to be uncorrelated. This approach points towards a limited number of simple structures which show the minimum complexity a neutrino mass model must generally involve to account for the data. These basic structures essentially lead to only 4 relations between the neutrino observables. We emphasize that 2 of these relations, |sin theta_13|=(tan theta_23/cos delta)*(1-tan theta_12)/(1+tan theta_12) and |sin theta_13| = sin theta_12 R^1/4, with R= Delta m^2_21/Delta m^2_32, have several distinctive properties. First, they hold not only with a minimum number of parameters, but also for complete classes of more general models. Second, any value of theta_13 within the T2K and MINOS ranges can be obtained from these relations by taking into account small perturbations. Third, they turn out to be the pivot relations of models with approximate conservation of lepton number, which allow the seesaw interactions to induce observable flavour violating processes, such as mu -> e gamma and tau -> mu gamma. Finally, in specific cases of this kind, these structures have the rather unique property to allow a full reconstruction of the seesaw Lagrangian from low energy data.Comment: 13 pages, 3 figure

    The Potential Impact of Heparanase Activity and Endothelial Damage in COVID-19 Disease

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    SARS-CoV-2 was first detected in 2019 in Wuhan, China. It has been found to be the most pathogenic virus among coronaviruses and is associated with endothelial damage resulting in respiratory failure. Determine whether heparanase and heparan sulfate fragments, biomarkers of endothelial function, can assist in the risk stratification and clinical management of critically ill COVID-19 patients admitted to the intensive care unit. We investigated 53 critically ill patients with severe COVID-19 admitted between March and April 2020 to the University Hospital RWTH Aachen. Heparanase activity and serum levels of both heparanase and heparan sulfate were measured on day one (day of diagnosis) and day three in patients with COVID-19. The patients were classified into four groups according to the severity of ARDS. When compared to baseline data (day one), heparanase activity increased and the heparan sulfate serum levels decreased with increasing severity of ARDS. The heparanase activity significantly correlated with the lactate concentration on day one (r = 0.34, p = 0.024) and on day three (r = 0.43, p = 0.006). Heparanase activity and heparan sulfate levels correlate with COVID-19 disease severity and outcome. Both biomarkers might be helpful in predicting clinical course and outcomes in COVID-19 patients

    DEVELOPMENT OF INACTIVATED POLIO VACCINE FROM ATTENUATED SABIN STRAINS FOR CLINICAL STUDIES AND TECHNOLOGY-TRANSFER PURPOSES

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    Recently, responding to WHO’s call for new polio vaccines, the development of Sabin-IPV (injectable, formalin-Inactivated Polio Vaccine, based on attenuated ‘Sabin’ polio virus strains) was initated at NVI. This activity plays an important role in the WHO polio eradication strategy. The use of Sabin instead of wild-type Salk polio strains will provide additional safety during vaccine production. Initially, the Sabin-IPV production process will be based on the scale-down model of the current, and well-established, Salk-IPV process. In parallel, process development, optimization and formulation research is being carried out to further modernize the process and reduce cost per dose. The lab-scale accelerated process development, product characterization, clinical lot production, and preparations for technology transfer will be discussed. Multivariate data analysis (MVDA) was applied on data from current IPV production (more than 60 Vero cell culture based runs) to extract relevant information, like operating ranges. Subsequently, based on the MVDA analysis, a 3-L scale-down model of the current twin 750-L bioreactors has been setup. Currently, in this lab-scale process, cell and virus culture approximate the large-scale and process improvement studies are in progress. This includes the application of increased cell densities, animal component free media, and DOE optimization in multiple parallel bioreactors. Also, results will be shown from large-scale (to prepare for future technology transfer) generation and testing of Master- and Working virus seedlots, and clinical lot (for phase I studies) production under cGMP conditions. The obtained product was used for immunogenicity studies in rats. It was shown that Sabin-IPV induces a good immune response, and a comparison will be made to regular Salk-IPV. Finally, technology transfer to vaccine manufacturers in low and middle–income countries will take place. For that, an international Sabin-IPV manufacturing course, including practical training at pilot-scale, is being setup

    Survey of the needs of patients with spinal cord injury: impact and priority for improvement in hand function in tetraplegics\ud

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    Objective: To investigate the impact of upper extremity deficit in subjects with tetraplegia.\ud \ud Setting: The United Kingdom and The Netherlands.\ud \ud Study design: Survey among the members of the Dutch and UK Spinal Cord Injury (SCI) Associations.\ud \ud Main outcome parameter: Indication of expected improvement in quality of life (QOL) on a 5-point scale in relation to improvement in hand function and seven other SCI-related impairments.\ud \ud Results: In all, 565 subjects with tetraplegia returned the questionnaire (overall response of 42%). Results in the Dutch and the UK group were comparable. A total of 77% of the tetraplegics expected an important or very important improvement in QOL if their hand function improved. This is comparable to their expectations with regard to improvement in bladder and bowel function. All other items were scored lower.\ud \ud Conclusion: This is the first study in which the impact of upper extremity impairment has been assessed in a large sample of tetraplegic subjects and compared to other SCI-related impairments that have a major impact on the life of subjects with SCI. The present study indicates a high impact as well as a high priority for improvement in hand function in tetraplegics.\ud \u
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