1,040 research outputs found

    Impact of POD modes energy redistribution on flow reconstruction for unsteady flows of impulsively started airfoils and wings

    Get PDF
    Obtaining accurate CFD solutions of unsteady flows during the design process ofan aircraft can be a highly-demanding task in terms of computational and time resources. A common practice is the recourse to Reduced Basis Methods (RBM), which manage to reduce the number of degrees of freedom to be solved yet allow preserving high accuracy, as opposed for example to low-fidelity methods like vortex-lattice or panel methods. RBM based on Proper Orthogonal Decomposition have been extensively studied and adopted but limitations are observed when trying to solve unsteady problems, where the temporal sequence of snapshots and the evolving nonlinear dynamics of the flow field need to be addressed carefully while building the reduced model. The present work investigates the problem of the accuracy in reconstructing nonlinear unsteady fluid flows by means of RBM methods for a specific class of impulsively started lifting bodies. The classical snapshot POD approachand a recent variant named Spectral POD will be comparatively studied to assess their capacity to reconstruct unsteady flow fields typical of aerospace applications. The periodic motion past a cylinder will be considered first as a benchmark testwhile the impulsive start of a 2D three element airfoil and a 3D wing in high-lift configurations will be considered as use cases

    Support to Design for Air Traffic Management: An Approach with Agent-Based Modelling and Evolutionary Search

    Get PDF
    To enhance Air Traffic Management (ATM) and meet the future traffic demand and environmental requirements, present ATM system is going to be modified (SESAR Joint Undertaking, 2017), designing new services to be integrated in future architecture considering the evolution of present fragmented structure of the airspace and the entanglement of air routes. Such a change process is complicated due to the nature of ATM, which is a large-scale Socio-Technical System (STS), typically involving a complex interaction between humans, machines and the environment. In such kind of systems, managing their evolution is a complex and difficult task since the social and technical implications of any proposed concept should be fully assessed before a choice is made whether or not to proceed with the related development. Often, simulation tools are also used to support the design of the concept itself by enabling what-if-analyses. However, these may be too effort and time consuming due to the exponential growth of the required analysis cases. A quite common mismatch between the performance evaluations in simulated conditions and those achieved in real life is represented by the partial assessment of human aspects that can be performed throughout the new concept lifecycle from its lowest maturity level up to “ready to market”. The proposed work defines an approach to support the design of new ATM solutions, including the evaluation on human behaviour. The approach adopts a combined paradigm, which involves Agent-Based Modelling and Simulation (ABMS) to specify and analyse the ATM models, and Agent-based Evolutionary Search (AES) to optimize the design of the new solutions. A specific case study is used to demonstrate the effectiveness of the proposed approach. Transition from Direct Routing Airspace (DRA) to Free Routing Airspace (FRA), respectively described by Solution #32 and Solution #33 in the SESAR solutions catalogue (SESAR Joint Undertaking, 2017), is used for both validation and experimentation activities. In detail, the proposed experimentation case regards the design of sector collapsing/decollapsing configuration to optimize controller workloads. The achieved results are presented and discussed

    Neutralization of IFN-γ reverts clinical and laboratory features in a mouse model of macrophage activation syndrome.

    Get PDF
    BACKGROUND: The pathogenesis of macrophage activation syndrome (MAS) is not clearly understood: a large body of evidence supports the involvement of mechanisms similar to those implicated in the setting of primary hemophagocytic lymphohistiocytosis. OBJECTIVE: We sought to investigate the pathogenic role of IFN-γ and the therapeutic efficacy of IFN-γ neutralization in an animal model of MAS. METHODS: We used an MAS model established in mice transgenic for human IL-6 (IL-6TG mice) challenged with LPS (MAS mice). Levels of IFN-γ and IFN-γ-inducible chemokines were evaluated by using real-time PCR in the liver and spleen and by means of ELISA in plasma. IFN-γ neutralization was achieved by using the anti-IFN-γ antibody XMG1.2 in vivo. RESULTS: Mice with MAS showed a significant upregulation of the IFN-γ pathway, as demonstrated by increased mRNA levels of Ifng and higher levels of phospho-signal transducer and activator of transcription 1 in the liver and spleen and increased expression of the IFN-γ-inducible chemokines Cxcl9 and Cxcl10 in the liver and spleen, as well as in plasma. A marked increase in Il12a and Il12b expression was also found in livers and spleens of mice with MAS. In addition, mice with MAS had a significant increase in numbers of liver CD68+ macrophages. Mice with MAS treated with an anti-IFN-γ antibody showed a significant improvement in survival and body weight recovery associated with a significant amelioration of ferritin, fibrinogen, and alanine aminotransferase levels. In mice with MAS, treatment with the anti-IFN-γ antibody significantly decreased circulating levels of CXCL9, CXCL10, and downstream proinflammatory cytokines. The decrease in CXCL9 and CXCL10 levels paralleled the decrease in serum levels of proinflammatory cytokines and ferritin. CONCLUSION: These results provide evidence for a pathogenic role of IFN-γ in the setting of MAS

    Arteritic Anterior Ischemic Optic Neuropathy Treated with Intravenous Prostaglandin E1 and Steroids.

    Get PDF
    Arteritic anterior ischemic optic neuropathy (AAION) is an acute ischemia of the posterior ciliary arteries and/or ophthalmic artery due to inflammation. Therapy is immediate intervention with systemic steroids, especially to protect against vision loss in the other eye. The addition of a potent vasodilator to the steroids could help restore ocular blood flow and improve visual acuity. The objective of the current report was to present the use of prostaglandin E(1) (PGE(1)) - a powerful vasodilator of the microcirculation - in the treatment of AAION. Two patients with AAION were treated with intravenous steroids and PGE(1). The visual acuity improved from 4/50 (less than 20/200) to 6/10 (20/35) in one patient and from 1/50 (20/400) to 1/10 (20/200) in the second patient. The visual fields in both patients maintained small central islands of vision. No complications due to the use of PGE(1) were seen. Intravenous PGE(1) should be considered in addition to steroids in cases of AAION to immediately restore blood flow to the optic nerve and improve visual acuity while the steroids reduce the inflammation

    Academic expectations profiles of spanish and portuguese higher education students

    Get PDF
    Las expectativas académicas de los estudiantes son hoy reconocidas como una variable importante en la explicación de su adaptación y éxito académico. Esa importancia es mayor en los alumnos del primer año, ya que, frecuentemente presentan expectativas iniciales muy elevadas que no siempre llegan a concretarse. Con la pretensión de conocer cuáles son esas expectativas iniciales, el trabajo que se presenta analiza el perfil de las mismas en estudiantes de Enseñanza Superior (ES) de primer año. La muestra está compuesta por 719 estudiantes de diversas titulaciones académicas de las Universidades de Vigo-Campus de Ourense y Minho. A los participantes se les aplicó el Cuestionario de Percepciones Académicas (CPA). Los resultados han sido analizados tomando la nacionalidad y el ámbito de estudio (cientifico, juridico-social, tecnológico). Los resultados muestran que los estudiantes portugueses tienden a presentar expectativas más elevadas en general, traduciéndose en una valoración superior de su entrada en la Universidad. A su vez, considerando las siete dimensiones de expectativas evaluadas, se comprueba un perfil similar para ambos países en relación a las expectativas más o menos valoradas. Se destacan las expectativas de obtener una formación que permita acceder a un buen empleo o carrera, en primer lugar, y las expectativas de tener en la Universidad oportunidades de desarrollo personal y social, en segundo lugar, como las más valoradas por los estudiantes.Academic expectations are recognized as an important variable for students’ adjustment and academic success. This importance is higher for first year students, because they often present initial expectations that may not be met. Aiming at identifying these initial expectations, this study presents and analyses the profile of first year students' academic expectations. The sample included 719 students attending different undergraduate programs at University of Vigo - Campus of Ourense, and at University of Minho. Participants completed the Academic Perceptions Questionnaire (APQ). Analyses were based on students’ nationality and study domain (scientific, juridical-social, technological). Results show that Portuguese students present higher expectations, in general, which shows they attribute a higher value to their access to University. On the other hand, and regarding the seven dimensions of assessed expectations, we can see that this difference in average scores is not structural, because there is a similar pattern of higher and lower expectations, for both countries. The most valued expectations are, in first place, expectations of having an education that will lead to a good job or career, and in second place, expectations of having opportunities of personal and social development in University

    Osteochondral impaction of the posterior acetabular surface without cortical fracture of any wall or column: an undescribed pattern of acetabular injury

    Get PDF
    Surgical treatment of a unusual acetabular fracture is described. This fracture was characterized by impaction and breaking down of the posterior articular surface and comminution of lamina quadrilatera lower portion, without cortical fracture of both columns. The fracture was treated surgically through the Kocher–Langenbeck approach. A small hole was created in the acetabulum posterior wall, the impacted fragment was reduced, and the bone defect was filled with autologous bone from the greater trochanter. A plate was shaped in order to fix both bone graft and fractured fragment

    Enhancing the early student experience

    Get PDF
    This paper is concerned with identifying how the early student experience can be enhanced in order to improve levels of student retention and achievement. The early student experience is the focus of this project as the literature has consistently declared the first year to be the most critical in shaping persistence decisions. Programme managers of courses with high and low retention rates have been interviewed to identify activities that appear to be associated with good retention rates. The results show that there are similarities in the way programmes with high retention are run, with these features not being prevalent on programmes with low retention. Recommendations of activities that appear likely to enhance the early student experience are provided

    Known drugs identified by structure-based virtual screening are able to bind sigma-1 receptor and increase growth of huntington disease patient-derived cells

    Get PDF
    Huntington disease (HD) is a devastating and presently untreatable neurodegenerative disease characterized by progressively disabling motor and mental manifestations. The sigma-1 receptor (σ1R) is a protein expressed in the central nervous system, whose 3D structure has been recently determined by X-ray crystallography and whose agonists have been shown to have neuro-protective activity in neurodegenerative diseases. To identify therapeutic agents against HD, we have implemented a drug repositioning strategy consisting of: (i) Prediction of the ability of the FDA-approved drugs publicly available through the ZINC database to interact with σ1R by virtual screening, followed by computational docking and visual examination of the 20 highest scoring drugs; and (ii) Assessment of the ability of the six drugs selected by computational analyses to directly bind purified σ1R in vitro by Surface Plasmon Resonance and improve the growth of fibro-blasts obtained from HD patients, which is significantly impaired with respect to control cells. All six of the selected drugs proved able to directly bind purified σ1R in vitro and improve the growth of HD cells from both or one HD patient. These results support the validity of the drug repositioning procedure implemented herein for the identification of new therapeutic tools against HD

    Clinical features of patients with type 2 diabetes with and without Covid-19: a case control study (CoViDiab I)

    Get PDF
    Aims: To evaluate whether subjects with diabetes hospitalized for Coronavirus disease-19 (Covid-19) represent a subgroup of patients with high-risk clinical features compared to patients with diabetes without Covid-19. Methods: In this case-control study 79 patients with type 2 diabetes out of 354 adults hospitalized for Covid-19 and 158 controls with type 2 diabetes but without Covid-19, matched for age and gender, were enrolled. Medical history and concomitant therapies were retrieved from medical charts and compared between cases and controls, controlling for confounders. Results: Fully-adjusted multivariate logistic regression model showed that previous CVD history did not differ between patients with and without Covid-19 (odds ratio 1.40, 95% confidence interval [CI]: 0.59–3.32, p = 0.45). A higher prevalence of chronic obstructive pulmonary disease (COPD) (OR 3.72, 95%CI: 1.42–9.72, p = 0.007) and of chronic kidney disease (CKD) (OR 3.08, 95%CI: 1.18–8.06, p = 0.022) and a lower prevalence of ever smokers (OR 0.30, 95%CI: 0.13–0.67, p = 0.003), of users of lipid lowering agents (OR 0.26, 95%CI: 0.12–0.54, p < 0.001), and of anti-hypertensive drugs (OR 0.39, 95%CI: 0.16–0.93, p = 0.033) were found among cases. Conclusions: CVD prevalence does not differ between people with diabetes with and without Covid-19 requiring hospitalization. An increased prevalence of COPD and of CKD in Covid-19 patients with type 2 diabetes is suggested. These findings aid to clarify the relationship between underlying conditions and SARS-CoV-2 infection in the high-risk group of patients with diabetes

    Inverse Modeling for MEG/EEG data

    Full text link
    We provide an overview of the state-of-the-art for mathematical methods that are used to reconstruct brain activity from neurophysiological data. After a brief introduction on the mathematics of the forward problem, we discuss standard and recently proposed regularization methods, as well as Monte Carlo techniques for Bayesian inference. We classify the inverse methods based on the underlying source model, and discuss advantages and disadvantages. Finally we describe an application to the pre-surgical evaluation of epileptic patients.Comment: 15 pages, 1 figur
    corecore