33 research outputs found

    Observation of Z production in proton-lead collisions at LHCb

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    The first observation of Z boson production in proton-lead collisions at a centre-of-mass energy per proton-nucleon pair of root(s) N N = 5TeV is presented. The data sample corresponds to an integrated luminosity of 1.6 nb(-1) collected with the LHCb detector. The Z candidates are reconstructed from pairs of oppositely charged muons with pseudorapidities between 2.0 and 4.5 and transverse momenta above 20 GeV/c. The invariant dimuon mass is restricted to the range 60-120 GeV/c. The Z production cross-section is measured to be sigma(Z ->mu+mu-) (fwd) = 13.5(-4.0)(+5.4)(stat.) +/- 1.2(syst.) nb in the direction of the proton beam and sigma(Z ->mu+mu-) (bwd) = 10.7(-5.1)(+8.4)(stat.) +/- 1.0(syst.) nb in the direction of the lead beam, where the first uncertainty is statistical and the second systematic

    Economic consequences of investing in anti-HCV antiviral treatment from the Italian NHS perspective : a real-world-based analysis of PITER data

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    OBJECTIVE: We estimated the cost consequence of Italian National Health System (NHS) investment in direct-acting antiviral (DAA) therapy according to hepatitis C virus (HCV) treatment access policies in Italy. METHODS: A multistate, 20-year time horizon Markov model of HCV liver disease progression was developed. Fibrosis stage, age and genotype distributions were derived from the Italian Platform for the Study of Viral Hepatitis Therapies (PITER) cohort. The treatment efficacy, disease progression probabilities and direct costs in each health state were obtained from the literature. The break-even point in time (BPT) was defined as the period of time required for the cumulative costs saved to recover the Italian NHS investment in DAA treatment. Three different PITER enrolment periods, which covered the full DAA access evolution in Italy, were considered. RESULTS: The disease stages of 2657 patients who consecutively underwent DAA therapy from January 2015 to December 2017 at 30 PITER clinical centres were standardized for 1000 patients. The investment in DAAs was considered to equal €25 million, €15 million, and €9 million in 2015, 2016, and 2017, respectively. For patients treated in 2015, the BPT was not achieved, because of the disease severity of the treated patients and high DAA prices. For 2016 and 2017, the estimated BPTs were 6.6 and 6.2 years, respectively. The total cost savings after 20 years were €50.13 and €55.50 million for 1000 patients treated in 2016 and 2017, respectively. CONCLUSIONS: This study may be a useful tool for public decision makers to understand how HCV clinical and epidemiological profiles influence the economic burden of HCV

    Mathematical Programming techniques in Water Network Optimization

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    In this article we survey mathematical programming approaches to problems in the field of drinking water distribution network optimization. Among the predominant topics treated in the literature, we focus on two different, but related problem classes. One can be described by the notion of network design, while the other is more aptly termed by network operation. The basic underlying model in both cases is a nonlinear network flow model, and we give an overview on the more specific modeling aspects in each case. The overall mathematical model is a Mixed Integer Nonlinear Program having a common structure with respect to how water dynamics in pipes are described. Finally, we survey the algorithmic approaches to solve the proposed problems and we discuss computation on various types of water networks

    LA CORONECTOMIA DI UN MOLARE MANDIBOLARE CARIATO: FOLLOW-UP A 18 MESI

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    Obiettivo: follow-up a 18 mesi in un caso di coronectomia di un dente molare cariat

    An MINLP Solution Method for a Water Network Problem

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    We propose a solution method for a water-network optimization problem using a nonconvex continuous NLP relaxation and an MINLP search. We report successful computational experience using available MINLP software on problems from the literature and on difficult real-world instances

    Iterative EM Reconstruction of Cardiac Small Animal PET Images Using System Point Spread Function Modelling and MAP with Anatomical Priors

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    The goal of this work was to improve the image quality of small animal PET images by introducing in the reconstruction process the true system point spread function (PSF) and an anatomical image prior. Simulations were performed using a mouse heart phantom (myocardium and ventricles) and a comparison between standard EM reconstruction and EM with PSF modelling and anatomical prior was performed. The system PSF was assumed to be a Gaussian function and its Full Width Half Maximum (FWHM) was modelled to be spatially variant in order to simulate the different spatial resolution inside the scanner field of view. A visual comparison of the images reconstructed with the standard EM and with the proposed image reconstruction method showed that the reconstructed images look much sharper and are very close to the true ones when using EM with PSF modelling and anatomical prior

    Partial Volume Correction of Small Animal PET Cardiac Dynamic Images Using Iterative Reconstruction: Effects on Glucose Metabolic Rate Measurement

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    Small animal positron emission tomography (PET) image quantitation is severely affected by partial volume effect (PVE) caused by the spatial resolution of PET tomographs. The aim of this work was to reduce the PVE using a modified iterative expectation maximization (EM) reconstruction algorithm. The goal of the method was to increase the accuracy of tracer concentration values in order to obtain an in vivo better estimate of physiological parameters. The performance of the proposed correction method was evaluated by calculating left ventricle and myocardium mean value using simulated cardiac fluorodeoxyglucose (FDG) dynamic images
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