247 research outputs found

    Investigation of hypersonic flow in the vki h3 wind tunnel: From facility characterization to boundary-layer interaction over low-temperature ablators

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    This work deals with the characterization, in terms of operating conditions, of the H3 hypersonic wind tunnel of the von Karman Institute for Fluid Dynamics (VKI), thus providing a detailed and structured benchmark for the evaluation of testing capabilities in hypersonic wind tunnels, and with the experimental study of the interaction between the boundary layer and the ablation process of low temperature ablative materials. The flow characteristics of the test section of the H3 WT have been assessed by using a pitot rake, for a wider range of operating conditions with respect to previous calibrations. A CFD analysis of the diffuser-ejector system has been carried out to assess its performance, and an experimental test campaign has been performed in order to validate the CFD analyses and completely characterize the facility operating conditions. Finally, a series of experiments with models of increasing size and different shapes has been carried out to determine the blockage effect in the tunnel test section. The H3 WT is then employed to study the boundary layer interaction with the ablative process on low temperature ablative models. These models have been built after having appropriately designed the sintering system. The Planar Laser Induced Fluorescence method has been applied to visualize the flow behavior: a laminar-turbulent transition due to the ablation process has been observed, together with the main flow structures

    Health-related quality of life and the burden of prolonged seizures in noninstitutionalized children with epilepsy

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    OBJECTIVE: This study aimed to provide information on the burden of illness and health-related quality of life (HRQoL) in children with epilepsy who experience prolonged acute convulsive seizures (PACS) in the community setting, and to investigate factors that may predict poor HRQoL in this population. METHODS: Noninstitutionalized children (aged 3–16 years) who had experienced at least one PACS within the past year and had currently prescribed PACS rescue medication were enrolled in a cross-sectional study in Germany, Italy, Spain, and the United Kingdom (Practices in Emergency and Rescue medication For Epilepsy managed with Community-administered Therapy 3 [PERFECT-3]). Clinicians, parents/guardians, and patients completed web-based questionnaires regarding clinical characteristics, PACS frequency, and day-to-day impairment. Patients' HRQoL was rated by clinicians, parents/guardians, and patients themselves using the 5-dimension EuroQol questionnaire (EQ-5D) and summarized as a utility score. Potential predictors of poor HRQoL were tested in individual univariate generalized linear models and a global multivariable model. RESULTS: Enrolled children (N = 286) had experienced 1–400 PACS (median: 4) in the past year. Clinicians reported that 216/281 patients (76.9%) had learning disabilities of varying severity. Mean EQ-5D utility scores rated by clinicians (n = 279), parents (n = 277), and patients (n = 85) were 0.52 (standard deviation: 0.41), 0.51 (0.39), and 0.74 (0.29), respectively. Increasing PACS frequency, increasing severity of learning disability, and specialist school attendance were significantly associated with decreasing EQ-5D utility score. In the multivariable model, having learning disabilities was the best predictor of poor HRQoL. SIGNIFICANCE: Health-related quality of life was very poor in many children with epilepsy whose PACS were managed with rescue medication in the community, with learning disability being the most powerful predictor of patients' HRQoL. Mean EQ-5D utility scores were lower (worse) than published values for many other chronic disorders, indicating that optimal treatment should involve helping children and their families to manage learning disabilities and day-to-day impairments, in addition to preventing seizures

    Evaluation of Rotor Blade Models for Rotor Outwash

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    In this work Computational Fluid Dynamics is used as a tool for rotor outwash evaluation. The paper concentrates on the validation of the method, presents different modelling approaches and concludes with suggestions on the use of the method for detailed simulations of rotor outwash. The required computer resources for the detailed computations of the wake are also discussed

    Safety of SARS-CoV2 vaccination and COVID-19 short-term outcome in pediatric acquired demyelinating disorders of central nervous system: A single center experience

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    IntroductionConcern of a correlation between disease relapse in patients with acquired demyelinating disorders of central nervous system (CNS) and SARS-CoV2 vaccines has been raised. In this single center study, we retrospectively evaluated safety of SARS-CoV2 vaccination and COVID-19 short-term outcome in pediatric acquired demyelinating disorders of CNS. Materials and methodsPatients with multiple sclerosis (MS), myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD) and neuromyelitis optica spectrum disorder (NMOSD) with disease onset before 18 years of age were included. Demographic and clinical data, and information regarding previous SARS-CoV-2 infection and vaccination were collected. ResultsWe included nine patients with MOGAD. Six patients received SARS-CoV2 vaccination and complained pain at injection site while only one had fever and fatigue. Median follow-up was 28 weeks (range 20-48). Seven patients had COVID-19 occurring with mild flu-like symptoms and median follow-up was 28 weeks (range 24-34). Nobody had disease relapse. Five patients with NMOSD were included. All patients received SARS-CoV2 vaccination (BNT162b2-Pfizer-BioNTech). The median follow-up was 20 weeks (range 14-24) and only two patients complained pain at injection site, fever and fatigue. Three patients had also COVID-19 with mild flu-like symptoms, despite two of them being under immunosuppressive treatment. Lastly, forty-three patients with MS were included. 35 out of 43 received SARS-CoV2 vaccination with a median follow-up of 24 weeks (range 8-36). Fourteen patients had no side effects, while 21 complained mild side effects (mainly pain at injection site) and one experienced a disease relapse with complete recovery after steroid therapy. At vaccination, all but one were under treatment. Sixteen patients had COVID-19 occurring with mild symptoms. DiscussionCOVID-19 outcome was good although many patients were under immunosuppressive treatment. Vaccine-related side effects were frequent but were mild and self-limited. Only one MS patient had a post-vaccination relapse with complete recovery after steroid therapy. In conclusion, our data support the safety of SARS-CoV-2 vaccines in pediatric MS, MOGAD and NMOSD

    An Exploratory Study of Field Failures

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    Field failures, that is, failures caused by faults that escape the testing phase leading to failures in the field, are unavoidable. Improving verification and validation activities before deployment can identify and timely remove many but not all faults, and users may still experience a number of annoying problems while using their software systems. This paper investigates the nature of field failures, to understand to what extent further improving in-house verification and validation activities can reduce the number of failures in the field, and frames the need of new approaches that operate in the field. We report the results of the analysis of the bug reports of five applications belonging to three different ecosystems, propose a taxonomy of field failures, and discuss the reasons why failures belonging to the identified classes cannot be detected at design time but shall be addressed at runtime. We observe that many faults (70%) are intrinsically hard to detect at design-time

    Definition and diagnostic criteria of sleep-related hypermotor epilepsy

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    The syndrome known as nocturnal frontal lobe epilepsy is recognized worldwide and has been studied in a wide range of clinical and scientific settings (epilepsy, sleep medicine, neurosurgery, pediatric neurology, epidemiology, genetics). Though uncommon, it is of considerable interest to practicing neurologists because of complexity in differential diagnosis from more common, benign sleep disorders such as parasomnias, or other disorders like psychogenic nonepileptic seizures. Moreover, misdiagnosis can have substantial adverse consequences on patients' lives. At present, there is no consensus definition of this disorder and disagreement persists about its core electroclinical features and the spectrum of etiologies involved. To improve the definition of the disorder and establish diagnostic criteria with levels of certainty, a consensus conference using formal recommended methodology was held in Bologna in September 2014. It was recommended that the name be changed to sleep-related hypermotor epilepsy (SHE), reflecting evidence that the attacks are associated with sleep rather than time of day, the seizures may arise from extrafrontal sites, and the motor aspects of the seizures are characteristic. The etiology may be genetic or due to structural pathology, but in most cases remains unknown. Diagnostic criteria were developed with 3 levels of certainty: witnessed (possible) SHE, video-documented (clinical) SHE, and video-EEG-documented (confirmed) SHE. The main research gaps involve epidemiology, pathophysiology, treatment, and prognosis
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