46 research outputs found

    Performance of the ALICE experiment at the CERN LHC

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    ALICE is the heavy-ion experiment at the CERN Large Hadron Collider. The experiment continuously took data during the first physics campaign of the machine from fall 2009 until early 2013, using proton and lead-ion beams. In this paper we describe the running environment and the data handling procedures, and discuss the performance of the ALICE detectors and analysis methods for various physics observables

    Higher harmonic anisotropic flow measurements of charged particles in Pb-Pb collisions at 2.76 TeV

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    We report on the first measurement of the triangular v3v_3, quadrangular v4v_4, and pentagonal v5v_5 charged particle flow in Pb-Pb collisions at 2.76 TeV measured with the ALICE detector at the CERN Large Hadron Collider. We show that the triangular flow can be described in terms of the initial spatial anisotropy and its fluctuations, which provides strong constraints on its origin. In the most central events, where the elliptic flow v2v_2 and v3v_3 have similar magnitude, a double peaked structure in the two-particle azimuthal correlations is observed, which is often interpreted as a Mach cone response to fast partons. We show that this structure can be naturally explained from the measured anisotropic flow Fourier coefficients.Comment: 10 pages, 4 figures, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/387

    Multiplicity dependence of jet-like two-particle correlation structures in p-Pb collisions at 1asNN=5.02 TeV

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    Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p\u2013Pb collisions at a nucleon\u2013nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 < pT,assoc < pT,trig < 5.0 GeV/c is examined, to include correlations induced by jets originating from low momentum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range |\u3b7| < 0.9. The near-side long-range pseudorapidity correlations observed in high-multiplicity p\u2013Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton\u2013parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p\u2013Pb collisions. Further, the number scales only in the intermediate multiplicity region with the number of binary nucleon\u2013nucleon collisions estimated with a Glauber Monte-Carlo simulation

    Role of dietary factors, food habits and lifestyle in childhood obesity development. A position paper from the European Society for Paediatric Gastroenterology, Hepatology and Nutrition Committee on Nutrition

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    Childhood obesity has high societal and economic impact, but current treatment approaches are sub-optimal. In the last decade important studies have been conducted aiming to identify strategies to prevent obesity during critical periods of life. Updated recommendations for childhood obesity prevention are needed.We present data from systematic reviews and meta- analysis, RCTs and large observational studies, published from 2011 onwards, that consider the possible role of the following factors in obesity development: breastfeeding; macronutrient composition and method of complementary feeding; parenting style; dietary patterns; sugar-sweetened beverage consumption; eating behaviour (e.g. skipping breakfast, family dinners etc.); meal frequency and composition (fast foods, snacking), portion size; dietary modulators of gut microbiota (including pre-, pro-, and synbiotics); physical activity and sedentary behaviour. We used the Medline database and the Cochrane Library to search for relevant publications. Important research gaps were also identified.This position paper provides recommendations on dietary factors, food habits and lifestyle to prevent childhood obesity development, based on the available literature and expert opinion. Clinical research and high-quality trials are urgently needed to resolve numerous areas of uncertainty
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