4,444 research outputs found

    Detecting System Errors in Virtual Reality Using EEG Through Error-Related Potentials

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    When persons interact with the environment and experience or wit-ness an error (e.g. an unexpected event), a specific brain pattern,known as error-related potential (ErrP) can be observed in the elec-troencephalographic signals (EEG). Virtual Reality (VR) technologyenables users to interact with computer-generated simulated envi-ronments and to provide multi-modal sensory feedback. Using VRsystems can, however, be error-prone. In this paper, we investigatethe presence of ErrPs when Virtual Reality users face 3 types ofvisualization errors: (Te) tracking errors when manipulating virtualobjects, (Fe) feedback errors, and (Be) background anomalies. Weconducted an experiment in which 15 participants were exposed tothe 3 types of errors while performing a center-out pick and placetask in virtual reality. The results showed that tracking errors gener-ate error-related potentials, the other types of errors did not generatesuch discernible patterns. In addition, we show that it is possible todetect the ErrPs generated by tracking losses in single trial, with anaccuracy of 85%. This constitutes a first step towards the automaticdetection of error-related potentials in VR applications, paving theway to the design of adaptive and self-corrective VR/AR applicationsby exploiting information directly from the user’s brain

    Four conjectures in Nonlinear Analysis

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    In this chapter, I formulate four challenging conjectures in Nonlinear Analysis. More precisely: a conjecture on the Monge-Amp\`ere equation; a conjecture on an eigenvalue problem; a conjecture on a non-local problem; a conjecture on disconnectedness versus infinitely many solutions.Comment: arXiv admin note: text overlap with arXiv:1504.01010, arXiv:1409.5919, arXiv:1612.0819

    Dominance of Vaccine Serotypes in Pediatric Invasive Pneumococcal Infections in Portugal (2012-2015)

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    We evaluated the impact of continued 13-valent pneumococcal conjugate vaccine (PCV13) use in the private market (uptake of 61%) in pediatric invasive pneumococcal disease (pIPD) in Portugal (2012-2015). The most frequently detected serotypes were: 3 (n = 32, 13.8%), 14 (n = 23, 9.9%), 1 (n = 23, 9.9%), 7F (n = 15, 6.4%), 19A (n = 13, 5.6%), 6B and 15B/C (both n = 12, 5.2%), and 24F, 10A and 12B (all with n = 10, 4.3%). Taken together, non-PCV13 serotypes were responsible for 42.2% of pIPD with a known serotype. The use of PCR to detect and serotype pneumococci in both pleural and cerebrospinal fluid samples contributed to 18.1% (n = 47) of all pIPD. Serotype 3 was mostly detected by PCR (n = 21/32, 65.6%) and resulted from a relevant number of vaccine failures. The incidence of pIPD varied in the different age groups but without a clear trend. There were no obvious declines of the incidence of pIPD due to serotypes included in any of the PCVs, and PCV13 serotypes still accounted for the majority of pIPD (57.8%). Our study indicates that a higher vaccination uptake may be necessary to realize the full benefits of PCVs, even after 15 years of moderate use, and highlights the importance of using molecular methods in pIPD surveillance, since these can lead to substantially increased case ascertainment and identification of particular serotypes as causes of pIPD.info:eu-repo/semantics/publishedVersio

    Review of low-cost sensors for indoor air quality: Features and applications

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    Humans spend the majority of their time indoors, where they are potentially exposed to hazardous pollutants. Within this context, over the past few years, there has been an upsurge of low-cost sensors (LCS) for the measurement of indoor air pollutants, motivated both by recent technological advances and by increased awareness of indoor air quality (IAQ) and its potential negative health impacts. Although not meeting the performance requirements for reference regulatory-equivalent monitoring indoors, LCS can provide informative measurements, offering an opportunity for high-resolution monitoring, emission source identification, exposure mitigation and managing IAQ and energy efficiency, among others. This article discusses the strengths and limitations that LCS offer for applications in the field of IAQ monitoring; it provides an overview of existing sensor technologies and gives recommendations for different indoor applications, considering their performance in the complex indoor environment and discussing future trends

    Midwife-led birthing centres in four countries: a case study.

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    BACKGROUND: Midwives are essential providers of primary health care and can play a major role in the provision of health care that can save lives and improve sexual, reproductive, maternal, newborn and adolescent health outcomes. One way for midwives to deliver care is through midwife-led birth centres (MLBCs). Most of the evidence on MLBCs is from high-income countries but the opportunity for impact of MLBCs in low- and middle-income countries (LMICs) could be significant as this is where most maternal and newborn deaths occur. The aim of this study is to explore MLBCs in four low-to-middle income countries, specifically to understand what is needed for a successful MLBC. METHODS: A descriptive case study design was employed in 4 sites in each of four countries: Bangladesh, Pakistan, South Africa and Uganda. We used an Appreciative Inquiry approach, informed by a network of care framework. Key informant interviews were conducted with 77 MLBC clients and 33 health service leaders and senior policymakers. Fifteen focus group discussions were used to collect data from 100 midwives and other MLBC staff. RESULTS: Key enablers to a successful MLBC were: (i) having an effective financing model (ii) providing quality midwifery care that is recognised by the community (iii) having interdisciplinary and interfacility collaboration, coordination and functional referral systems, and (iv) ensuring supportive and enabling leadership and governance at all levels. CONCLUSION: The findings of this study have significant implications for improving maternal and neonatal health outcomes, strengthening healthcare systems, and promoting the role of midwives in LMICs. Understanding factors for success can contribute to inform policies and decision making as well as design tailored maternal and newborn health programmes that can more effectively support midwives and respond to population needs. At an international level, it can contribute to shape guidelines and strengthen the midwifery profession in different settings

    Non-compartment model to compartment model pharmacokinetics transformation meta-analysis – a multivariate nonlinear mixed model

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    Background To fulfill the model based drug development, the very first step is usually a model establishment from published literatures. Pharmacokinetics model is the central piece of model based drug development. This paper proposed an important approach to transform published non-compartment model pharmacokinetics (PK) parameters into compartment model PK parameters. This meta-analysis was performed with a multivariate nonlinear mixed model. A conditional first-order linearization approach was developed for statistical estimation and inference. Results Using MDZ as an example, we showed that this approach successfully transformed 6 non-compartment model PK parameters from 10 publications into 5 compartment model PK parameters. In simulation studies, we showed that this multivariate nonlinear mixed model had little relative bias (<1%) in estimating compartment model PK parameters if all non-compartment PK parameters were reported in every study. If there missing non-compartment PK parameters existed in some published literatures, the relative bias of compartment model PK parameter was still small (<3%). The 95% coverage probabilities of these PK parameter estimates were above 85%. Conclusions This non-compartment model PK parameter transformation into compartment model meta-analysis approach possesses valid statistical inference. It can be routinely used for model based drug development

    Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

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    The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal
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