297 research outputs found

    On forward and inverse uncertainty quantification for models involving hysteresis operators

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    Parameters within hysteresis operators modeling real world objects have to be identified from measurements and are therefore subject to corresponding errors. To investigate the influence of these errors, the methods of Uncertainty Quantification (UQ) are applied. Results of forward UQ for a play operator with a stochastic yield limit are presented. Moreover, inverse UQ is performed to identify the parameters in the weight function in a Prandtl-Ishlinskiĭ operator and the uncertainties of these parameters

    Handling multicollinearity in quantile regression through the use of principal component regression

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    In many fields of applications, linear regression is the most widely used statistical method to analyze the effect of a set of explanatory variables on a response variable of interest. Classical least squares regression focuses on the conditional mean of the response, while quantile regression extends the view to conditional quantiles. Quantile regression is very convenient, whereas classical parametric assumptions do not hold and/or when relevant information lies in the tails and therefore the interest is in modeling the conditional distribution of the response at locations different from the mean. A situation common to most regression applications is the presence of strong correlations between predictors. This leads to the well-known problem of collinearity. While the effects of collinearity on least squares estimates are well investigated, this is not the case for quantile regression estimates. This paper aims to explore the collinearity problem in quantile regression. First, a simulation study analyses the problem concerning different degrees of collinearity and various response distributions. Then the paper proposes using regression on latent components as a possible solution to collinearity in quantile regression. Finally, a case study shows the assessment of the quality of service in the presence of highly correlated predictors

    Proof of principle of a fuel injector based on a magnetostrictive actuator

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    One of the goals of modern internal combustion engines is the NOx-soot trade-off, and this would be better achieved by a better control of the fuel injection. Moreover, this feature can be also useful for high-performance hydraulic systems. Actual fuel injection technology either allows only the control of the injection time or it is based on very complex mechanical-hydraulic systems, as in the case of piezo-actuators. This work describes the basic steps that brought the authors to the realization of a concept fuel injector based on a Terfenol-D magnetostrictive actuator that could overcome the previous issues, being both simple and controllable. The study provides the design, development, and a feasibility analysis of a magnetostrictive actuator for fuel injection, by providing a basic magneto-static analysis of the actuator, the adaptation of a suitable standard fuel injector, and its experimental testing in a lab environment, with different shapes and amplitude of the reference signal to follow

    First outbreak of Pepper vein yellows virus infecting sweet pepper in Italy

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    Sweet pepper (Capsicum annum) is an economically important crop worldwide, including Sicily where about 4,000 hectares are grown each year. In October 2015, severe symptoms not previously reported by growers in the horticultural area of the province of Trapani (Sicily, Italy) were observed on sweet pepper plants in eight different greenhouses. Symptoms included upward leaf curling, internodal shortening and interveinal yellowing. Symptoms were more evident in the upper part of the plants. These symptoms were reminiscent of those caused by poleroviruses. In the greenhouse, symptoms were evident in about 35% of the plants. Three samples per greenhouse (24 in total) were collected for analysis

    In-Field LAMP Detection of Flavescence Dorée Phytoplasma in Crude Extracts of the Scaphoideus titanus Vector

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    One of the most destructive diseases affecting grapevine in Europe is caused by Flavescence Dorée phytoplasma (FDp), which belongs to the 16Sr-V group and is a European Union quarantine pathogen. Although many molecular techniques such as loop-mediated isothermal amplification (LAMP) are widely used for the rapid detection of FDp in infected grapevine plants, there is no developed isothermal amplification assay for FDp detection in the insect vectors that are fundamental for the spread of the disease. For this reason, a simple in-field real-time LAMP protocol was optimized and developed for the specific detection of FDp in the insect vector Scaphoideus titanus. The LAMP assay was optimized to work with crude insect extracts obtained by manually shaking a single insect in a buffer for 5 min. Such a simple, sensitive, specific, economic, and user-friendly LAMP assay allowed the detection of FDp in S. titanus in less than half an hour, directly in the field. The developed insect tissue preparation procedure, combined with the LAMP protocol, promptly revealed the presence of FDp in infected S. titanus directly in the vineyards, allowing for monitoring of the spread of the pathogen in the field and to apply timely strategies required for the mandatory control of this pathogen

    指冷丝弦吟怨曲,声翻经典响新雷——评弹《雷雨》的艺术魅力与文化价值

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    LIBO is a proton accelerator that operates at 3 GHz, the same frequency as the one adopted in the about 7500 electron linacs used for radiotherapy all over the world. Such a high frequency was chosen to obtain a large gradient (on average more than 10 MV/m), and thus a short linac (about 15 m) to boost the energy of the protons, extracted at about 60 MeV from a cyclotron, up to the 200 MeV needed for the treatment of deep-seated tumours. This paper describes the design study of the full 3 GHz Side Coupled Linac (modular structure, nine modules) and the construction and tests of the LIBO prototype (first module), which was built to accelerate protons from 62 to 74 MeV with an RF peak power of 4.4 MW. The items discussed are the beam dynamics parameters of the module (longitudinal and transverse acceptances), the constructional elements and procedures, the accuracies of the various mechanical elements, the cooling system, the RF tuning, the RF measurement and the RF power tests. These tests showed that, after a short conditioning time, the gradient in each of the four tanks of the module could reach 28.5 MV/m, much larger than the nominal project value (15.8 MV/m). The last section of the paper describes the successful acceleration tests performed at the Laboratori Nazionali del Sud of INFN in Catania with a solid-state 3 GHz modulator lent by IBA

    Emergence and phylodynamics of Citrus tristeza virus in Sicily, Italy

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    [EN] Citrus tristeza virus (CTV) outbreaks were detected in Sicily island, Italy for the first time in 2002. To gain insight into the evolutionary forces driving the emergence and phylogeography of these CTV populations, we determined and analyzed the nucleotide sequences of the p20 gene from 108 CTV isolates collected from 2002 to 2009. Bayesian phylogenetic analysis revealed that mild and severe CTV isolates belonging to five different clades (lineages) were introduced in Sicily in 2002. Phylogeographic analysis showed that four lineages co-circulated in the main citrus growing area located in Eastern Sicily. However, only one lineage (composed of mild isolates) spread to distant areas of Sicily and was detected after 2007. No correlation was found between genetic variation and citrus host, indicating that citrus cultivars did not exert differential selective pressures on the virus. The genetic variation of CTV was not structured according to geographical location or sampling time, likely due to the multiple introduction events and a complex migration pattern with intense co- and recirculation of different lineages in the same area. The phylogenetic structure, statistical tests of neutrality and comparison of synonymous and nonsynonymous substitution rates suggest that weak negative selection and genetic drift following a rapid expansion may be the main causes of the CTV variability observed today in Sicily. Nonetheless, three adjacent amino acids at the p20 N-terminal region were found to be under positive selection, likely resulting from adaptation events.A.W. and S.F.E. were supported by grant BFU2012-30805 from the Spanish Secretaria de Estado de Investigacion, Desarrollo e Innovacion and by a grant 22371 from the John Templeton Foundation. The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of the John Templeton Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Davino, S.; Willemsen, A.; Panno. Stefano; Davino, M.; Catara, A.; Elena Fito, SF.; Rubio, L. (2013). Emergence and phylodynamics of Citrus tristeza virus in Sicily, Italy. PLoS ONE. 8:66700-66700. doi:10.1371/journal.pone.0066700S66700667008Domingo, E., & Holland, J. J. (1997). RNA VIRUS MUTATIONS AND FITNESS FOR SURVIVAL. Annual Review of Microbiology, 51(1), 151-178. doi:10.1146/annurev.micro.51.1.151Grenfell, B. T. (2004). Unifying the Epidemiological and Evolutionary Dynamics of Pathogens. Science, 303(5656), 327-332. doi:10.1126/science.1090727Moya, A., Holmes, E. C., & González-Candelas, F. (2004). The population genetics and evolutionary epidemiology of RNA viruses. 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F., Guerri, J., Moreno, P., Sambade, A., Rubio, L., … Vives, M. C. (2009). Contribution of recombination and selection to molecular evolution of Citrus tristeza virus. Journal of General Virology, 90(6), 1527-1538. doi:10.1099/vir.0.008193-0Vives, M. C., Rubio, L., Sambade, A., Mirkov, T. E., Moreno, P., & Guerri, J. (2005). Evidence of multiple recombination events between two RNA sequence variants within a Citrus tristeza virus isolate. Virology, 331(2), 232-237. doi:10.1016/j.virol.2004.10.037D’Urso, F., Sambade, A., Moya, A., Guerri, J., & Moreno, P. (2003). Variation of haplotype distributions of two genomic regions of Citrus tristeza virus populations from eastern Spain. Molecular Ecology, 12(2), 517-526. doi:10.1046/j.1365-294x.2000.01747.xSambade, A., Rubio, L., Garnsey, S. M., Costa, N., Muller, G. W., Peyrou, M., … Moreno, P. (2002). Comparison of viral RNA populations of pathogenically distinct isolates of Citrus tristeza virus : application to monitoring cross-protection. 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    Observation of Collider Muon Neutrinos with the SND@LHC Experiment

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    We report the direct observation of muon neutrino interactions with the SND@LHC detector at the Large Hadron Collider. A dataset of proton-proton collisions at √ s = 13.6 TeV collected by SND@LHC in 2022 is used, corresponding to an integrated luminosity of 36.8 fb − 1 . The search is based on information from the active electronic components of the SND@LHC detector, which covers the pseudorapidity region of 7.2 < η < 8.4 , inaccessible to the other experiments at the collider. Muon neutrino candidates are identified through their charged-current interaction topology, with a track propagating through the entire length of the muon detector. After selection cuts, 8 ν μ interaction candidate events remain with an estimated background of 0.086 events, yielding a significance of about 7 standard deviations for the observed ν μ signal
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