249 research outputs found

    Experimental assessment of drag reduction by traveling waves in a turbulent pipe flow

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    We experimentally assess the capabilities of an active, open-loop technique for drag reduction in turbulent wall flows recently introduced by Quadrio et al. [J. Fluid Mech., v.627, 161, (2009)]. The technique consists in generating streamwise-modulated waves of spanwise velocity at the wall, that travel in the streamwise direction. A proof-of-principle experiment has been devised to measure the reduction of turbulent friction in a pipe flow, in which the wall is subdivided into thin slabs that rotate independently in the azimuthal direction. Different speeds of nearby slabs provide, although in a discrete setting, the desired streamwise variation of transverse velocity. Our experiment confirms the available DNS results, and in particular demonstrates the possibility of achieving large reductions of friction in the turbulent regime. Reductions up to 33% are obtained for slowly forward-traveling waves; backward-traveling waves invariably yield drag reduction, whereas a substantial drop of drag reduction occurs for waves traveling forward with a phase speed comparable to the convection speed of near-wall turbulent structures. A Fourier analysis is employed to show that the first harmonics introduced by the discrete spatial waveform that approximates the sinusoidal wave are responsible for significant effects that are indeed observed in the experimental measurements. Practical issues related to the physical implementation of this control scheme and its energetic efficiency are briefly discussed.Comment: Article accepted by Phys. Fluids. After it is published, it will be found at http://pof.aip.or

    Experimental investigation of a helicopter rotor with Gurney flaps

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    The present work describes an experimental activity carried out to investigate the performance of Gurney flaps on a helicopter rotor model in hovering. The four blades of the articulated rotor model were equipped with Gurney flaps positioned at 95% of the aerofoil chord, spanning 14% of the rotor radius. The global aerodynamic loads and torque were measured for three Gurney flap configurations characterised by different heights. The global measurements showed an apparent benefit produced by Gurney flaps in terms of rotor performance with respect to the clean blade configuration. Particle image velocimetry surveys were also performed on the blade section at 65% of the rotor radius with and without the Gurney flaps. The local velocity data was used to complete the characterisation of the blade aerodynamic performance through the evaluation of the sectional aerodynamic loads using the the control volume approach

    Isolation of Leptospira sp. from an equine abortion

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    The differences observed between females and males were statistically significant (p 1⁄4 0, 001). It was detected a virus infection of equine Viral Arteritis in 53% of the samples obtained in feral donkeys, which could indicate some degree of viral circulation in these animal populations. It suggests later studies that they allow to characterize these viruses of donkeys, to see his phylogeny. Chile is free of EVA in horses, the disease has not been detected in domestic horses and it is of compulsory notification. The detection of antibodies anti-vEVA inwild species was communicated to the World Organization for Animal Health (OIE)

    Immune thrombotic thrombocytopenic purpura: Personalized therapy using ADAMTS-13 activity and autoantibodies

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    Recently, treatment of immune-mediated thrombotic thrombocytopenic purpura (ITTP) has changed with the advent of caplacizumab in clinical practice. The International Working Group (IWG) has recently integrated the ADAMTS-13 activity/autoantibody monitoring in consensus outcome definitions. We report three ITTP cases during the coronavirus disease 2019 pandemic, that received a systematic evaluation of ADAMTS-13 activity and autoantibodies. We describe how the introduction of caplacizumab and ADAMTS-13 monitoring could change the management of ITTP patients and discuss whether therapeutic choices should be based on the clinical response alone. ADAMTS-13 activity/antibodies were assessed every 5 days. Responses were evaluated according to updated IWG outcome definitions. These kinetics, rather than clinical remission, guided the therapy, allowing early and safe caplacizumab discontinuation and sensible administration of rituximab. Caplacizumab was cautiously discontinued after achieving ADAMTS-13 complete remission. These cases illustrate that prospective ADAMTS-13 evaluation and use of updated IWG definitions may improve real-life patients’ management in the caplacizumab era

    Distribution, abundance and biological features of anglerfish (Lophius piscatorius and Lophius budegassa) (Osteichthyes: Lophiiformes) in the Mediterranean Sea

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    The distribution and biological features of anglerfish (Lophius piscatorius and L. budegassa) in the Mediterranean Sea were analysed from trawl surveys data (MEDITS project, years 1994-1999). The above-mentioned species were widely distributed in the Mediterranean, but differences in abundance were found according to geographic sectors and depths. Most of the collected specimens belonged to the first length cohorts and length distributions also differed at macroarea levels. Mean sizes at female sexual maturity were estimated at 68.5 cm and 66.2 cm total length, respectively for L. piscatorius and L. budegassaPublicado

    Identification of Rickettsia species in ticks from ruminants in Lebanon

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    Rickettsia are tick-borne emerging pathogens recognized as important agents of human tick-borne diseases worldwide. Aim of this study was the identification and characterization of Spotted Fever Group (SFG) rickettsiae in ticks from ruminants in Lebanon. The study concerned 88 ticks collected in June 2014 from 30 Lebanese farms of ruminants and identified according morphological keys. Total DNA was extracted and used to identify and characterize Rickettsia spp. DNA through PCR and sequencing of fragments of 17 kDa protein, ompA, ompB, gltA, atpA, dnaK, dnaA, recA and 16S rRNA. Five different tick species were found: Hyalomma anatolicum (n=6), Rhipicephalus annulatus (n=56), Rhipicephalus bursa (n=1), Rhipicephalus sanguineus (n=6) and Rhipicephalus turanicus (n=19). A prevalence of 68.2% was found at the first screening performed amplyfing Rickettsia spp. 16S rRNA. Among these Rickettsia positive samples, 17 were identified at the species level and 43 as SFG rickettsiae based on the multigene genotyping strategy. ‘Candidatus Rickettsia barbariae’, an emerging member of the rickettsial SFG, was identified in 9 samples. R. massiliae, R. aeschlimannii and R. africae were identified in four, three and one tick, respectively, confirming the presence of SFG Rickettsia spp. involved in human diseases. SFG rickettsiae with public health relevance were found in ticks collected in Lebanon, where the widespread distribution of tick vectors and possible livestock animal hosts in contact with humans may favor transmission to humans. Funded by IZSSI 02/13, IZSSI 10/14, COMPARE, Grant 643476 and by UCLM Own Research Program. Thanks to Pippo Bono for technical support

    Ruxolitinib discontinuation syndrome: incidence, risk factors, and management in 251 patients with myelofibrosis

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    none36Ruxolitinib discontinuation syndrome: incidence, risk factors, and management in 251 patients with myelofibrosisopenPalandri F.; Palumbo G.A.; Elli E.M.; Polverelli N.; Benevolo G.; Martino B.; Abruzzese E.; Tiribelli M.; Tieghi A.; Latagliata R.; Cavazzini F.; Bergamaschi M.; Binotto G.; Crugnola M.; Isidori A.; Caocci G.; Heidel F.; Pugliese N.; Bosi C.; Bartoletti D.; Auteri G.; Cattaneo D.; Scaffidi L.; Trawinska M.M.; Stella R.; Ciantia F.; Pane F.; Cuneo A.; Krampera M.; Semenzato G.; Lemoli R.M.; Iurlo A.; Vianelli N.; Cavo M.; Breccia M.; Bonifacio M.Palandri, F.; Palumbo, G. A.; Elli, E. M.; Polverelli, N.; Benevolo, G.; Martino, B.; Abruzzese, E.; Tiribelli, M.; Tieghi, A.; Latagliata, R.; Cavazzini, F.; Bergamaschi, M.; Binotto, G.; Crugnola, M.; Isidori, A.; Caocci, G.; Heidel, F.; Pugliese, N.; Bosi, C.; Bartoletti, D.; Auteri, G.; Cattaneo, D.; Scaffidi, L.; Trawinska, M. M.; Stella, R.; Ciantia, F.; Pane, F.; Cuneo, A.; Krampera, M.; Semenzato, G.; Lemoli, R. M.; Iurlo, A.; Vianelli, N.; Cavo, M.; Breccia, M.; Bonifacio, M
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