56 research outputs found
Parental and household smoking and the increased risk of bronchitis, bronchiolitis and other lower respiratory infections in infancy: systematic review and meta-analysis
<p>Abstract</p> <p>Background</p> <p>Passive smoke exposure increases the risk of lower respiratory infection (LRI) in infants, but the extensive literature on this association has not been systematically reviewed for nearly ten years. The aim of this paper is to provide an updated systematic review and meta-analysis of studies of the association between passive smoking and LRI, and with diagnostic subcategories including bronchiolitis, in infants aged two years and under.</p> <p>Methods</p> <p>We searched MEDLINE and EMBASE (to November 2010), reference lists from publications and abstracts from major conference proceedings to identify all relevant publications. Random effect pooled odds ratios (OR) with 95% confidence intervals (CI) were estimated.</p> <p>Results</p> <p>We identified 60 studies suitable for inclusion in the meta-analysis. Smoking by either parent or other household members significantly increased the risk of LRI; odds ratios (OR) were 1.22 (95% CI 1.10 to 1.35) for paternal smoking, 1.62 (95% CI 1.38 to 1.89) if both parents smoked, and 1.54 (95% CI 1.40 to 1.69) for any household member smoking. Pre-natal maternal smoking (OR 1.24, 95% CI 1.11 to 1.38) had a weaker effect than post-natal smoking (OR 1.58, 95% CI 1.45 to 1.73). The strongest effect was on bronchiolitis, where the risk of any household smoking was increased by an OR of 2.51 (95% CI 1.96 to 3.21).</p> <p>Conclusions</p> <p>Passive smoking in the family home is a major influence on the risk of LRI in infants, and especially on bronchiolitis. Risk is particularly strong in relation to post-natal maternal smoking. Strategies to prevent passive smoke exposure in young children are an urgent public and child health priority.</p
Direct photon elliptic flow in Pb-Pb collisions at root s(NN)=2.76 TeV
The elliptic flow of inclusive and direct photons was measured at mid-rapidity in two centrality classes 0-20% and 20-40% in Pb-Pb collisions at root s(NN) = 2.76 TeV by ALICE. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the detector material with the e(broken vertical bar)e pairs reconstructed in the central tracking system. The results of the two methods were combined and the direct-photon elliptic flow was extracted in the transverse momentum range 0.9 < p(T) < 6.2 GeV/c. A comparison to RHIC data shows a similar magnitude of the measured direct-photon elliptic flow. Hydrodynamic and transport model calculations are systematically lower than the data, but are found to be compatible. (C) 2018 The Author. Published by Elsevier B.V.Peer reviewe
Higher moment fluctuations of identified particle distributions from ALICE
Cumulants of conserved charges fluctuations are regarded as a potential tool
to study the criticality in the QCD phase diagram and to determine the
freeze-out parameters in a model-independent way. At LHC energies, the
measurements of the ratio of the net-baryon (net-proton) cumulants can be used
to test the lattice QCD predictions. In this work, we present the first
measurements of cumulants of the net-proton number distributions up to
order in Pb--Pb collisions at = 2.76 and 5.02 TeV as a
function of collision centrality. We compare our cumulant ratios results with
the STAR experiment net-proton results measured in the first phase of the Beam
Energy Scan program at RHIC. The results can be used to obtain the chemical
freeze-out parameters at LHC.Comment: 4 pages, 3 figures, Proceedings of XXVIIth International Conference
on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2018
Spin alignment measurements using vector mesons with ALICE detector at the LHC
We present new measurements related to spin alignment of K*(0) vector
mesons at mid-rapidity for Pb-Pb collisions at root s(NN) = 2.76 and
5.02 TeV. The spin alignment measurements are carried out with respect
to production plane and 2nd order event plane. At low p(T) the spin
density matrix element rho(00) for K*(0) is found to have values
slightly below 1/3, while it is consistent with 1/3, i.e. no spin
alignment, at high p(T). Similar values of rho(00) are observed with
respect to both production plane and event plane. Within statistical and
systematic uncertainties, rho(00) values are also found to be
independent of root s(NN). rho(00) also shows centrality dependence with
maximum deviation from 1/3 for mid-central collisions with respect to
both the kinematic planes. The measurements for K*(0) in pp collisions
at root s = 13 TeV and for K-s(0) (a spin 0 hadron) in 20-40\% central
Pb-Pb collisions at root s(NN) = 2.76 TeV are consistent with no spin
alignment
Muon physics at forward rapidity with the ALICE detector upgrade
ALICE is the experiment specifically designed to study the Quark-Gluon
Plasma (QGP) in heavy-ion collisions at the CERN LHC. The ALICE detector
will be upgraded during the Long Shutdown 2, planned for 2019-2020, in
order to cope with the maximum interaction rate of 50 kHz of Pb-Pb
collisions foreseen for Runs 3 and 4. The ambitious programme of
high-precision measurements, expected for muon physics after 2020,
requires an upgrade of the front-end and readout electronics of the
existing Muon Spectrometer. This concerns the Cathode Pad Chambers (CPC)
used for tracking and the Resistive Plate Chambers (RPC) used for
triggering and for muon identification. The Muon Forward Tracker (MFT),
an internal tracker added in front of the front absorber of the existing
Muon Spectrometer, is also part of the ALICE detector upgrade programme.
It is based on an assembly of circular planes made of Monolithic Active
Pixel Sensors (MAPS), covering the pseudorapidity range 2.5 < eta < 3.6.
The MFT will improve present measurements and enable new ones. A
selection of results from physics performance studies will be presented,
together with an overview of the technical aspects of the upgrade
project
Measuring (KSK +/-)-K-0 interactions using pp collisions at root s=7 TeV
We present the first measurements of femtoscopic correlations between the K-S(0) and K-+/- particles in pp collisions at root s = 7 TeV measured by the ALICE experiment. The observed femtoscopic correlations are consistent with final-state interactions proceeding solely via the a(0)(980) resonance. The extracted kaon source radius and correlation strength parameters for (KSK-)-K-0 are found to be equal within the experimental uncertainties to those for (KSK+)-K-0. Results of the present study are compared with those from identical-kaon femtoscopic studies also performed with pp collisions at root s = 7 TeV by ALICE and with a (KSK +/-)-K-0 measurement in Pb-Pb collisions at root s(NN) = 2.76 TeV. Combined with the Pb-Pb results, our pp analysis is found to be compatible with the interpretation of the a (980) having a tetraquark structure instead of that of a diquark. (C) 2018 Published by Elsevier B.V.Peer reviewe
Light (anti-)nuclei production and elliptic flow at the LHC with ALICE
Results on the production of stable light nuclei, including deuterons,
He-3, He-4 and the corresponding anti-nuclei, in Pb-Pb collisions at
root s(NN) = 2.76 TeV and root s(NN) = 5.02 TeV are presented and
compared with theoretical predictions and with the results in small
systems to provide insight into the production mechanisms of
(anti-)nuclei at colliders.
The experimental results are presented giving a critical view of their
comparison to the expectations from coalescence and hydrodynamic models
that aim at describing both the p(T)-spectra and the elliptic flow
Open heavy-flavour production and elliptic flow in p-Pb collisions at the LHC with ALICE
Measurements of open heavy flavour production in p-A collisions allow
the investigation of Cold Nuclear Matter effects. In addition, they are
an important tool for a complementary investigation of the long-range
correlations found in small systems in the light flavour sector. In this
work, production measurements of D mesons at mid-rapidity in p-Pb
collisions at root S-NN = 5.02 TeV are reported. Production yields are
also reported for the heavy-flavour hadron decay electrons at central
rapidity at root(SNN) = 5.02 and 8.16 TeV. The elliptic flow (nu(2)) of
heavy-flavour hadron decay electrons in high multiplicity p-Pb
collisions at root(SNN) = 5.02 TeV is found to be positive with a
significance larger than 5 sigma
Upsilon suppression at forward rapidity in Pb-Pb collisions at root s(NN)=5.02 TeV
Inclusive Υ(1S) and Υ(2S) production have been measured in Pb–Pb collisions at the centre-of-mass energy per nucleon–nucleon pair √sNN = 5.02 TeV, using the ALICE detector at the CERN LHC. The Υ mesons are reconstructed in the centre-of-mass rapidity interval 2.5 < y < 4 and in the transverse-momentum range pT < 15 GeV/c, via their decays to muon pairs. In this Letter, we present results on the inclusive Υ(1S) nuclear modification factor RAA as a function of collision centrality, transverse momentum and rapidity. The Υ(1S) and Υ(2S) RAA, integrated over the centrality range 0–90%, are 0.37± 0.02(stat) ± 0.03(syst) and 0.10 ± 0.04(stat) ± 0.02(syst), respectively, leading to a ratio RΥ(2S)/RΥ(1S) of 0.28±0.12(stat)±0.06(syst). The observed Υ(1S) suppression increases with the centrality of the collision and no significant variation is observed as a function of transverse momentum and rapidity
Dielectron and heavy-quark production in inelastic and high-multiplicity proton-proton collisions at root s=13 TeV
The measurement of dielectron production is presented as a function of invariant mass and transverse momentum (p T ) at midrapidity (|y e |<0.8) in proton–proton (pp) collisions at a centre-of-mass energy of s=13 TeV. The contributions from light-hadron decays are calculated from their measured cross sections in pp collisions at s=7 TeV or 13 TeV. The remaining continuum stems from correlated semileptonic decays of heavy-flavour hadrons. Fitting the data with templates from two different MC event generators, PYTHIA and POWHEG, the charm and beauty cross sections at midrapidity are extracted for the first time at this collision energy: dσ cc¯ /dy| y=0 =974±138(stat.)±140(syst.)±214(BR)μb and dσ bb¯ /dy| y=0 =79±14(stat.)±11(syst.)±5(BR)μb using PYTHIA simulations and dσ cc¯ /dy| y=0 =1417±184(stat.)±204(syst.)±312(BR)μb and dσ bb¯ /dy| y=0 =48±14(stat.)±7(syst.)±3(BR)μb for POWHEG. These values, whose uncertainties are fully correlated between the two generators, are consistent with extrapolations from lower energies. The different results obtained with POWHEG and PYTHIA imply different kinematic correlations of the heavy-quark pairs in these two generators. Furthermore, comparisons of dielectron spectra in inelastic events and in events collected with a trigger on high charged-particle multiplicities are presented in various p T intervals. The differences are consistent with the already measured scaling of light-hadron and open-charm production at high charged-particle multiplicity as a function of p T . Upper limits for the contribution of virtual direct photons are extracted at 90% confidence level and found to be in agreement with pQCD calculations
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