1,129 research outputs found

    On special quadratic birational transformations of a projective space into a hypersurface

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    We study transformations as in the title with emphasis on those having smooth connected base locus, called "special". In particular, we classify all special quadratic birational maps into a quadric hypersurface whose inverse is given by quadratic forms by showing that there are only four examples having general hyperplane sections of Severi varieties as base loci.Comment: Accepted for publication in Rendiconti del Circolo Matematico di Palerm

    Oral and craniofacial manifestations of Ellis-Van Creveld syndrome: A systematic review

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    Aim A systematic literature review on oral and craniofacial manifestations of Ellis-Van Creveld syndrome was performed. Methods From 2 databases were selected 74 articles using as key words "Ellis-Van Creveld" AND "Oral" OR "Craniofacial" OR "Dental" OR "Malocclusion". Prisma protocol was used to create an eligible list for the screening. Data were collected in a table to compare the clinical aspects found. Results From the first research emerged 350 articles, and only 72 of them were selected. Conclusion Through this analysis oral and cranio-facial manifestations of Ellis-Van Creveld syndrome were pointed out. Management of Ellis-Van Creveld syndrome requires a multidisciplinary approach involving different clinicians; dentists play an important role in early diagnosis and treatment of the patients

    Disposable versus reusable ureteroscopes. A prospective multicenter randomized comparison

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    Introduction: To compare reusable and disposable flexible ureteroscopes in terms of efficacy and safety for patients undergoing RIRS, with specific reference to post-operative complications and infection rates. Materials and methods: Patients with a renal stone eligible for RIRS were enrolled in this multicenter, randomized, clinical trial study. Patients were randomized into two groups: group A (90 patients) underwent RIRS with a reusable flexible ureteroscope and group B (90 patients) were treated with a disposable one. Results: The patients’ demographics, stones features and preoperative urine cultures were comparable between the groups. The SFRs were not significantly different (86,6% and 90,0% for group A and group B respectively, p = 0.11) and the mean cost for each procedure was comparable (2321 € in group A vs 2543 € in group B, p = 0.09). However, the days of hospitalization and of antibiotic therapy were higher in group A (p ≤ 0.05). The overall complication rate in group A was 8.8% whilst in group B it was 3.3% (p ≤ 0.05); in particular, group A exhibited a greater number of major complications (Clavien score IIIa-V). The overall postoperative infections rate was 16.6% in group A and 3.3% in group B (p ≤ 0.05). Furthermore, none of the patients in group B developed urosepsis or had a positive blood culture, while 3 patients in group A did (p < 0.05). Conclusions: The use of disposable ureteroscopes is characterized by significantly lower post-operative complications and infection rates, while having comparable costs and SFRs vis à vis reusable ureteroscopes

    Holmium laser enucleation of the prostate with Virtual Basket mode: faster and better control on bleeding

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    Background: To compare clinical intra and early postoperative outcomes between conventional Holmium laser enucleation of the prostate (HoLEP) and Holmium laser enucleation of the prostate using the Virtual Basket tool (VB-HoLEP) to treat benign prostatic hyperplasia (BPH). Methods: This prospective randomized study enrolled consecutive patients with BPH, who were assigned to undergo either HoLEP (n = 100), or VB-HoLEP (n = 100). All patients were evaluated preoperatively and postoperatively, with particular attention to catheterization time, operative time, blood loss, irrigation volume and hospital stay. We also evaluated the patients at 3 and 6 months after surgery and assessed maximum flow rate (Qmax), postvoid residual urine volume (PVR), the International Prostate Symptom Score (IPSS) and the Quality of Life score (QOLS). Results: No significant differences in preoperative parameters between patients in each study arm were found. Compared to HoLEP, VB-HoLEP resulted in less hemoglobin decrease (2.54 vs. 1.12 g/dl, P = 0.03) and reduced operative time (57.33 ± 29.71 vs. 42.99 ± 18.51 min, P = 0.04). HoLEP and VB-HoLEP detrmined similar catheterization time (2.2 vs. 1.9 days, P = 0.45), irrigation volume (33.3 vs. 31.7 l, P = 0.69), and hospital stay (2.8 vs. 2.7 days, P = 0.21). During the 6-month follow-up no significant differences in IPSS, Qmax, PVR, and QOLS were demonstrated. Conclusions: HoLEP and VB-HoLEP are both efficient and safe procedures for relieving lower urinary tract symptoms. VB-HoLEP was statistically superior to HoLEP in blood loss and operative time. However, procedures did not differ significantly in catheterization time, hospital stay, and irrigation volume. No significant differences were demonstrated in QOLS, IPSS, Qmax and PVR throughout the 6-month follow-up. Trial Registration: Current Controlled Trials ISRCTN72879639; date of registration: June 25th, 2015. Retrospectively registred

    A comparison among PCNL, Miniperc and Ultraminiperc for lower calyceal stones between 1 and 2 cm: A prospective, comparative, multicenter and randomised study

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    Background: Conventional Percutaneous Lithotripsy (PCNL) has been an effective, successful and easy approach for especially > 1 cm sized calyceal stones however risks of complications and nephron loss are inevitable. Our aim is to compare the efficacy and safety of PCNL, MiniPerc (MP) and UltraMiniPerc (UMP) for lower calyceal stones between 1 and 2 cm with a multicenter prospective randomized study. Methods: Between January 2015 and June 2018, 132 consecutive patients with single lower calyceal stone were enrolled. Patients were randomized in three groups; A: PCNL; B: MP; C: UMP. 44 patients for the Group A, 47 for Group B and 41 for Group C. Exclusion criterias were the presence of coagulation impairments, age of < 18 or > 75, presence of infection or serious comorbidities. Patients were controlled with computerized tomography scan after 3 months. A negative CT or an asymptomatic patient with stone fragments < 3 mm size were the criteria to assess the stone-free status. Patient characteristics, stone free rates (SFR) s, complications and re-treatment rates were analyzed. Results: The mean stone size were 16.38, 16.82 and 15.23 mm respectively in Group A, B and C(p = 0.34). The overall SFR was significantly higher in Group A (86.3%) and B (82.9%) as compared to Group C (78%)(p < 0.05). The re-treatment rate was significantly higher in Group C (12.1%) and complication rates was higher in Group A (13.6%) as compared to others(p < 0.05). The hospitalization was significantly shorter in Group C compared to Group A (p = 0.04). Conclusions: PCNL and MP showed higher efficacy than UMP to obtain a better SFR. Auxiliary and re-treatment rates were higher in UMP. On the other hand for such this kind of stones PCNL had more complications. Overall evaluation favors MP as a better indication in stones 1-2 cm size

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Standalone vertex finding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

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    A measurement of the production cross-section for top quark pairs(\ttbar) in pppp collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron ee or muon μ\mu) with large missing transverse energy and at least four jets, and dilepton (eeee, μμ\mu\mu or eμe\mu) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be 12.2±3.912.2 \pm 3.9 events and 2.5±0.62.5 \pm 0.6 events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

    Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

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    A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction
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