233 research outputs found

    Simulations of the flow around a circular cylinder by variational multi-scale large-eddy simulation

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    The aim of the present work is to validate and investigate the behaviour of a Variational Multiscale formulation (VMS) in the Large Eddy Simulation (LES) of the flow around a circular cylinder at Reynolds number, based on the free-stream velocity and on the diameter, equal to 3900. Simulations are carried out with three different eddy-viscosity closure models. Furthermore, the effect of grid resolution investigated, by using two different grid: a coarser grid of about 2.9*10^5 nodes and a finer one with approximately 1.13*10^6 nodes. For all simulations comparisons with the experimental data and with the results of the other LES in the letterature are provided

    Mapping the distribution of Well-Being in Europe beyond national borders

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    Well-being is a concept difficult to define and eventually harder to quantify. The idea of providing descriptions and metrics to evaluate well-being goes back to Aristotle (1095 bc) and from there an increasingly large number of studies attempted to quantify well-being of individuals and societies. Well-being is generally perceived as a description of the state of human life which always captured the attention of sociologists, economists, psychologist, politicians and citizens, making it a largely debated interdisciplinary topic. In particular in recent times, characterized by even increasing concerns related to the economic and the environmental situation, an increasing attention has been devoted to determining integrated descriptions to include all the aspects of human life. In addition, a large attention, demonstrated by the increasing literature on the topic, has also been devoted to the contribution of politics and societal organization in the progress toward well-being. The first part of this report tries to review the existing literature on well-being. Two main broad wellbeing approaches will be considered, the subjective and the objective approaches. For every one of them, the main definitions, the most important theoretical perspectives and the most relevant metrics and quantifications will be reported. The major contribution is to provide a synthesis of the vast literature that exists on the concept of well-being. In addition, by presenting the most recent well-being approach based on the integration between the objective and the subjective ones, an overview of the future directions of well-being investigations is also provided.JRC.H.2-Air and Climat

    Wearable device for swim assessment: a new ecologic approach for communication and analysis

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    This paper describes a wearable system for the assessment of swim performance focusing on the description of the system and especially on the novel method for data transmission in water, and the algorithm used for extracting some parameters for the qualitative assessment of the performance. We placed a 3-axes Inertial Measurement Unit (IMU) on the athlete's back in a specific swimsuit, which also allows for recording 1-lead ECG. The system and the algorithm have been tested on 13 trials with 10 subjects comparing the results with data extracted from video recording. The system demonstrated able and reliable to measure time and kinematic parameters of swimming

    Kaposi's sarcoma‐associated herpesvirus serology in Europe and Uuganda: Multicentre study with multiple and novel assays

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    AbstractA multicentre study was undertaken to define novel assays with increased inter‐assay concordance, sensitivity, specificity and predictive value for serological diagnosis of human herpesvirus type 8 (HHV‐8) infection. A total of 562 sera from European and Ugandan human immunodeficiency virus (HIV)‐infected or uninfected individuals with or without Kaposi's sarcoma (KS) and blood donors were examined under code by 18 different assays in seven European laboratories. Sera from KS patients and all non‐KS sera found positive by at least 70%, 80%, or 90% of the assays were considered "true positive." The validity of the assays was then evaluated by univariate logistic regression analysis. Two immunofluorescence assays (IFA) for detection of antibodies against HHV‐8 lytic (Rlyt) or latent (LLANA) antigens and two enzyme‐linked‐immunosorbent assays (ELISA) (M2, EK8.1) for detection of antibodies against HHV‐8 structural proteins were found to be highly concordant, specific, and sensitive, with odds ratios that indicated a high predictive value. When used together, the two IFA (Rlyt‐LLANA) showed the best combination of sensitivity (89.1%) and specificity (94.9%). The performance of these assays indicate that they may be used for the clinical management of individuals at risk of developing HHV‐8 associated tumours such as allograft recipients. J. Med. Virol. 65:123–132, 2001. © 2001 Wiley‐Liss, Inc

    Multi-Messenger Astronomy with Extremely Large Telescopes

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    The field of time-domain astrophysics has entered the era of Multi-messenger Astronomy (MMA). One key science goal for the next decade (and beyond) will be to characterize gravitational wave (GW) and neutrino sources using the next generation of Extremely Large Telescopes (ELTs). These studies will have a broad impact across astrophysics, informing our knowledge of the production and enrichment history of the heaviest chemical elements, constrain the dense matter equation of state, provide independent constraints on cosmology, increase our understanding of particle acceleration in shocks and jets, and study the lives of black holes in the universe. Future GW detectors will greatly improve their sensitivity during the coming decade, as will near-infrared telescopes capable of independently finding kilonovae from neutron star mergers. However, the electromagnetic counterparts to high-frequency (LIGO/Virgo band) GW sources will be distant and faint and thus demand ELT capabilities for characterization. ELTs will be important and necessary contributors to an advanced and complete multi-messenger network.Comment: White paper submitted to the Astro2020 Decadal Surve

    Parietal resting-state EEG alpha source connectivity is associated with subcortical white matter lesions in HIV-positive people

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    Objective Parietal resting-state electroencephalographic (rsEEG) alpha (8–10 Hz) source connectivity is abnormal in HIV-positive persons. Here we tested whether this abnormality may be associated with subcortical white matter vascular lesions in the cerebral hemispheres. Methods Clinical, rsEEG, and magnetic resonance imaging (MRI) datasets in 38 HIV-positive persons and clinical and rsEEG datasets in 13 healthy controls were analyzed. Radiologists visually evaluated the subcortical white matter hyperintensities from T2-weighted FLAIR MRIs (i.e., Fazekas scale). In parallel, neurophysiologists estimated the eLORETA rsEEG source lagged linear connectivity from parietal cortical regions of interest. Results Compared to the HIV participants with no/negligible subcortical white matter hyperintensities, the HIV participants with mild/moderate subcortical white matter hyperintensities showed lower parietal interhemispheric rsEEG alpha lagged linear connectivity. This effect was also observed in HIV-positive persons with unimpaired cognition. This rsEEG marker allowed good discrimination (area under the receiver operating characteristic curve > 0.80) between the HIV-positive individuals with different amounts of subcortical white matter hyperintensities. Conclusions The parietal rsEEG alpha source connectivity is associated with subcortical white matter vascular lesions in HIV-positive persons, even without neurocognitive disorders. Significance Those MRI-rsEEG markers may be used to screen HIV-positive persons at risk of neurocognitive disorders

    Avoiding the ask: a field experiment on altruism, empathy, and charitable giving’, mimeo

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    Abstract What triggers giving? We explore this in a randomized natural field experiment during the Salvation Army's annual campaign. Solicitors were at one or both of two main entrances to a supermarket, making the solicitation either easy or difficult to avoid. Additionally, solicitors were either silent, or asked "please give" to passersby. We observed over 17,000 passings over four days, and found dramatic avoidance of the solicitors, but only during a direct ask. Furthermore, asking increased donations 75%. Across all conditions, seeking the solicitor was exceedingly rare. The results do not support static views of altruism, such as inequity aversion, and instead highlight the importance of social cues and psychological features of the giver-receiver interaction. We argue that avoidance could evidence a lack of altruism or self-control strategy to deal with empathic reflexes to give. * A version of this paper constituted Trachtman's senior thesis at Harvard College, for which it was awarded the best thesis prize and summa cum laude honors. We would like to note that Trachtman took the lead responsibility in coordinating and executing the experiment. Erzo Luttmer provided exceptionally helpful advice along the way. We would also like to than

    Candidurie nosocomiali: analisi dei fattori di rischio, terapia ed evoluzione micologica. Risultati di una indagine nazionale

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    The multiple problems associated with the recovery of yeasts from urine specimens induced the Medical Mycology Committee (CoSM) of AMCLI to run a nationwide epidemiologic survey on candiduria in order to evaluate risk factors, involved species, treatment and outcome. Ten hospitals (Bergamo, Como, Crema, Novara,Varese,Ancona, Florence, Pescara, Palermo and Taranto) participated to this study, which was run on a 15-month period (October 1, 2001-December 31, 2002). Overall, 83 Data Forms were collected, regarding patients admitted to Intensive Care Units (45), Surgical (9) and Medical (29) wards. The most common risk factors were: bladder catheter, antibiotic therapy, parenteral nutrition, kidney failure, surgery. Candiduria, mostly asymptomatic, were often associated with fever and bacterial infections. Concurrent candidaemia was detected in 13 patients. Candida albicans was the most frequently recovered species, from both urine and blood, followed by C. glabrata. Other Candida species were occasionally isolated from urine specimens. Specific antifungal treatment was administered to 58% of the patients, mostly using fluconazole. The remaining subjects did not receive antimycotic therapy. Eradication of Candida from urine specimens was observed even without a specific therapy
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