2,295 research outputs found

    Elliptic and triangular flow of identified particles at ALICE

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    We report on the first measurements of elliptic and triangular flow for charged pions, kaons and anti-protons in lead-lead collisions at 2.76 TeV measured with the ALICE detector at the LHC. We compare the observed mass splitting of differential elliptic flow at LHC energies to RHIC measurements at lower energies and theory predictions. We test the quark coalescence picture with the quark number scaling of elliptic and triangular flow.Comment: 4 pages, 5 figures, Quark Matter 2011 conference proceeding

    The little finger ulnar palmar digital artery perforator flap: anatomical basis

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    PURPOSE: The aim of this study was to explore the cutaneous vascularization of the hypothenar region and investigate the anatomical basis for perforator propeller flaps for coverage of the flexor aspect of the little finger. METHODS: The area between the pisiform and the base of the little finger was studied in 14 hands of fresh cadavers injected with red latex. An oval flap 1.5 cm large was raised along the axis between these two points. Perforators going into the flap were dissected up to their origin from the ulnar palmar digital artery of the little finger, and their distance from the proximal edge of the A1 pulley was recorded. RESULTS: The mean number of perforator arteries entering the flap was 5.8 (range 4-8). A constant sizeable perforator was identified within 0.7 cm from the proximal margin of the A1 pulley in all 14 specimens. In the majority of cases (64 %), the most distal perforator was located at this level. Dissection of the flap was carried out suprafascially on the most distal perforator and 180° rotation allowed the flap to reach the flexor surface of the fifth finger. The donor site was closed primarily. CONCLUSION: Distal perforators of the ulnar palmar digital artery of the little finger are constantly found. Our anatomical findings support the possibility of raising a propeller perforator flap from the hypothenar region for coverage of the flexor aspect of the little finger. Its clinical application could provide a quick and straightforward single-stage option with a negligible donor-site morbidity for reconstruction of such defects

    Elliptic flow at high transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{NN}} = 2.76 TeV with the ALICE experiment

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    An observable that can be used to better constrain the mechanism responsible for the parton energy loss is the elliptic azimuthal event anisotropy, v2v_2. We report on measurements of v2v_2 for inclusive and identified charged particles in Pb-Pb collisions at sNN=2.76\sqrt{s_{NN}} = 2.76 TeV recorded by the ALICE experiment at the LHC. v2v_2 is presented for a wide range of particle transverse momentum up to pT=20p_T=20 GeV/c. The particle v2v_2 is finite, positive and approximately constant for pT>8p_T>8 GeV/c. The proton v2v_2 is higher than that of the pion up to about pT=8p_T=8 GeV/c. The results are compared to the measurements at lower energy reported by RHIC experiments.Comment: 4 pages, QM 2011 proceeding

    The Horn, Kink and Step, Dale: from few GeV to few TeV

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    Rich experimental data have been collected in heavy-ion collisions at high energies to study the properties of strongly interacting matter. As the theory of strong interactions, QCD, predicts asymptotic freedom, the created matter at sufficiently high temperature and density will be dominated by a state of quasi-free quarks and gluons referred to as the Quark-Qluon Plasma (QGP). Experimental signals for the onset of the QGP creation (the onset of the deconfinement) have been predicted within the statistical model for the early stage of nucleus-nucleus collisions. In this model the existence of two different phases is assumed: confined mater and the QGP, as well as a first order phase transition between them. Until recently, these predictions were confirmed only by the NA49 experiment at the CERN SPS. In this report recent results from STAR at RHIC/BNL and from ALICE at LHC/CERN, related to the onset of deconfinement, will be compared to published results from NA49

    Post-operative computed tomography imaging evaluation of ascending aorta surgery

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    Ascending thoracic aorta disease is often a life-threatening condition. Aortic aneurysm and aortic dissection are the most frequent ascending aorta diseases requiring surgical intervention. Surgical repair techniques of the ascending aorta are various; they include reconstruction of the ascending aorta by using a graft with or without a prosthetic valve, reconstruction with a composite artificial graft or using a biological graft, and reconstruction of the ascending aorta with a composite graft preserving the native valve and arch repair. The radiologist plays a key role in the identification of post-operative complications; differentiation from normal postoperative findings is fundamental. Our aim is to discuss the main diseases affecting the ascending aorta requiring surgery and the different techniques used to treat them. We also discuss the normal computed tomography (CT) imaging findings and after-surgery complications

    Role of computed tomography and magnetic resonance imaging in local complications of acute pancreatitis

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    Acute pancreatitis (AP) represents a pancreas inflammation of sudden onset that can present different degrees of severity. AP is a frequent cause of acute abdomen and its complications are still a cause of death. Biliary calculosis and alcohol abuse are the most frequent cause of AP. Computed tomography (CT) and magnetic resonance imaging (MRI) are not necessary for the diagnosis of AP but they are fundamental tools for the identification of the cause, degree severity and AP complications. AP severity assessment is in fact one of the most important issue in disease management. Contrast-enhanced CT is preferred in the emergency setting and is considered the gold standard in patients with AP. MRI is comparable to CT for the diagnosis of AP but requires much more time so it is not usually chosen in the emergency scenario. Complications of AP can be distinguished in localized and generalized. Among the localized complications, we can identify: acute peripancreatic fluid collections (APFC), pseudocysts, acute necrotic collections (ANC), walled off pancreatic necrosis (WOPN), venous thrombosis, pseudoaneurysms and haemorrhage. Multiple organ failure syndrome (MOFS) and sepsis are possible generalized complications of AP. In this review, we focus on CT and MRI findings in local complications of AP and when and how to perform CT and MRI. We paid also attention to recent developments in diagnostic classification of AP complications

    Imaging the COVID-19: A practical guide

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    The Coronavirus Disease 2019 (COVID-19) represents the first medical catastrophe of the new millennium. Although imaging is not a screening test for COVID-19, it plays a crucial role in evaluation and follow-up of COVID-19 patients. In this paper, we will review typical and atypical imaging findings of COVID-19

    Construction and Expected Performance of the Hadron Blind Detector for the PHENIX Experiment at RHIC

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    A new Hadron Blind Detector (HBD) for electron identification in high density hadron environment has been installed in the PHENIX detector at RHIC in the fall of 2006. The HBD will identify low momentum electron-positron pairs to reduce the combinatorial background in the e+e−e^{+}e^{-} mass spectrum, mainly in the low-mass region below 1 GeV/c2^{2}. The HBD is a windowless proximity-focusing Cherenkov detector with a radiator length of 50 cm, a CsI photocathode and three layers of Gas Electron Multipliers (GEM). The HBD uses pure CF4_{4} as a radiator and a detector gas. Construction details and the expected performance of the detector are described.Comment: QM2006 proceedings, 4 pages 3 figure

    Particle Production at Large Transverse Momentum with ALICE

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    We present transverse momentum distributions of inclusive charged particles and identified hadrons in pppp and Pb--Pb collisions at \rs= 2.76 TeV, measured by ALICE at the LHC. The Pb--Pb data are presented in intervals of collision centrality and cover transverse momenta up to 50 GeV/cc. Nuclear medium effects are studied in terms of the nuclear modification factor \raa. The results indicate a strong suppression of high-pTp_T particles in Pb--Pb collisions, consistent with a large energy loss of hard-scattered partons in the hot, dense and long-lived medium created at the LHC. We compare the preliminary results for inclusive charged particles to previous results from RHIC and calculations from energy loss models. Furthermore, we compare the nuclear modification factors of inclusive charged particles to those of identified π0\pi^0, π±\pi^{\pm}, Ks0^0_s, and Λ\Lambda.Comment: Talk given at Quark Matter 2011 conferenc
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