1,529 research outputs found
Cross Saharan transport of water vapour via recycled cold-pool outflows from moist convection
Very sparse data has previously limited observational studies of meteorological processes in the Sahara. We present an observed case of convectively-driven water vapour transport crossing the Sahara over 2.5 days in June 2012, from the Sahel in the south to the Atlas in the north. A daily cycle is observed, with deep convection in the evening generating moist cold pools that fed the next day’s convection; the convection then generated new cold pools, providing a vertical recycling of moisture. Trajectories driven by analyses were able to capture the direction of the transport but not its full extent, particularly at night when cold pools are most active, and analyses missed much of the water content of cold pools. The results highlight the importance of cold pools for moisture transport, dust and clouds, and demonstrate the need to include these processes in models in order to improve the representation of Saharan atmospher
Emergency department hyperoxia is associated with increased mortality in mechanically ventilated patients: A cohort study
Definitions of comorbid conditions. (DOCX 13 kb
Energy dependence of exclusive photoproduction off protons in ultra-peripheral p-Pb collisions at = 5.02 TeV
The ALICE Collaboration has measured the energy dependence of exclusive
photoproduction of vector mesons off proton targets in
ultra-peripheral p-Pb collisions at a centre-of-mass energy per nucleon pair
TeV. The ee and decay channels
are used to measure the cross section as a function of the rapidity of the
in the range , corresponding to an energy in the
p centre-of-mass in the interval GeV.
The measurements, which are consistent with a power law dependence of the
exclusive photoproduction cross section, are compared to previous
results from HERA and the LHC and to several theoretical models. They are found
to be compatible with previous measurements.Comment: 25 pages, 3 captioned figures, 3 tables, authors from page 19,
published version, figures at http://alice-publications.web.cern.ch/node/455
First measurement of production in pp collisions at = 7 TeV
The production of the charm-strange baryon is measured for
the first time at the LHC via its semileptonic decay into e
in pp collisions at TeV with the ALICE detector. The transverse
momentum () differential cross section multiplied by the branching
ratio is presented in the interval 1 8 GeV/ at
mid-rapidity, 0.5. The transverse momentum dependence of the
baryon production relative to the D meson production is
compared to predictions of event generators with various tunes of the
hadronisation mechanism, which are found to underestimate the measured
cross-section ratio.Comment: 22 pages, 6 captioned figures, 1 table, authors from page 17,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/412
Constraining the magnitude of the Chiral Magnetic Effect with Event Shape Engineering in Pb-Pb collisions at = 2.76$ TeV
In ultrarelativistic heavy-ion collisions, the event-by-event variation of
the elliptic flow reflects fluctuations in the shape of the initial state
of the system. This allows to select events with the same centrality but
different initial geometry. This selection technique, Event Shape Engineering,
has been used in the analysis of charge-dependent two- and three-particle
correlations in Pb-Pb collisions at TeV. The
two-particle correlator ,
calculated for different combinations of charges and , is
almost independent of (for a given centrality), while the three-particle
correlator
scales almost linearly both with the event and charged-particle
pseudorapidity density. The charge dependence of the three-particle correlator
is often interpreted as evidence for the Chiral Magnetic Effect (CME), a parity
violating effect of the strong interaction. However, its measured dependence on
points to a large non-CME contribution to the correlator. Comparing the
results with Monte Carlo calculations including a magnetic field due to the
spectators, the upper limit of the CME signal contribution to the
three-particle correlator in the 10-50% centrality interval is found to be
26-33% at 95% confidence level.Comment: 20 pages, 6 captioned figures, 1 tables, authors from page 15,
published version, figures at
http://aliceinfo.cern.ch/ArtSubmission/node/382
Risk-factors associated with extremely high cardiovascular risk of mid- and long-term mortality following myocardial infarction: An analysis of the Hyperlipidaemia Therapy in tERtiary Cardiological cEnTer (TERCET) Registry
Introduction: Risk-factor identification and risk stratification are prerequisites to the effective primary and secondary prevention of cardiovascular disease (CVD). Patients at the highest risk benefit the most from the intensive risk-factor reduction. However, high-risk patients’ group is heterogeneous, and it is increasingly recognised that there is an 'extreme-risk' category of patients who may require particularly close attention and intensive therapeutic approach. The aim of this study was to identify subgroups of patients at the highest risk of death following myocardial infarction (MI) that might be considered as those at extremely high CVD risk. Methods: We used data from 19,582 participants of the Hyperlipidaemia Therapy in tERtiary Cardiological cEnTer (TERCET) Registry (NCT03065543) of patients with ischaemic heart disease in Poland from 2006-present. Characteristics of 13,052 patients with chronic coronary syndromes (CCS) were compared with those of 4,295 patients with myocardial infarction (STEMI and 48 NSTEMI). Multivariable logistic regression with stepwise backward elimination was used to identify risk factors associated with mortality in the 12-36 months following the index hospitalisation. Results: The mortality rates were significantly higher in patients after MI than in patients with CCS. In the multivariable analysis, the risk factors most strongly associated with 12-month mortality in patients after MI were left ventricular ejection fraction (LVEF) lower than 35% (hazard ratio [HR] 3.83, 95% confidence interval [CI] 3.14-4.67), age >75 years (HR 1.91, 95%CI 1.55-2.35), multivessel coronary artery disease (HR 1.61, 95%CI 1.30-1.99), atrial fibrillation (HR 1.53, 95%CI 55 1.21-1.94) diabetes mellitus (HR 1.35, 95%CI 1.11-1.64) and increased LDL-C (HR per 1 mmol/l 56 1.09, 95%CI 1.01-1.19) or creatinine levels (HR per 10 µmol/L 1.04, 95% CI 1.04-1.05). The risk factors that influenced mortality after 24-36 months were consistent with those after 12 months, with additional low haemoglobin (20-25% risk increase per 1 mmol reduction) and chronic obstructive pulmonary disease (65% risk increase after 36 months). Conclusions: In our large, single-centre real-world analysis we identified the patients with the highest risk of death who could probably benefit the most from the most intensive therapy, and hence should be considered to be an 'extreme risk' population
Measurement of the production of charm jets tagged with D mesons in pp collisions at = 7 TeV
The production of charm jets in proton-proton collisions at a center-of-mass
energy of TeV was measured with the ALICE detector at the CERN
Large Hadron Collider. The measurement is based on a data sample corresponding
to a total integrated luminosity of , collected using a
minimum-bias trigger. Charm jets are identified by the presence of a D
meson among their constituents. The D mesons are reconstructed from their
hadronic decay DK. The D-meson tagged jets are
reconstructed using tracks of charged particles (track-based jets) with the
anti- algorithm in the jet transverse momentum range
and pseudorapidity
. The fraction of charged jets containing a D-meson
increases with from to . The distribution of D-meson tagged jets as a
function of the jet momentum fraction carried by the D meson in the
direction of the jet axis () is reported for two ranges
of jet transverse momenta, and
in the intervals
and , respectively. The
data are compared with results from Monte Carlo event generators (PYTHIA 6,
PYTHIA 8 and Herwig 7) and with a Next-to-Leading-Order perturbative Quantum
Chromodynamics calculation, obtained with the POWHEG method and interfaced with
PYTHIA 6 for the generation of the parton shower, fragmentation, hadronisation
and underlying event.Comment: 29 pages, 8 captioned figures, 3 tables, authors from page 24,
published version, figures at http://alice-publications.web.cern.ch/node/525
Heavy-flavour and quarkonium production in the LHC era: from proton-proton to heavy-ion collisions
This report reviews the study of open heavy-flavour and quarkonium production
in high-energy hadronic collisions, as tools to investigate fundamental aspects
of Quantum Chromodynamics, from the proton and nucleus structure at high energy
to deconfinement and the properties of the Quark-Gluon Plasma. Emphasis is
given to the lessons learnt from LHC Run 1 results, which are reviewed in a
global picture with the results from SPS and RHIC at lower energies, as well as
to the questions to be addressed in the future. The report covers heavy flavour
and quarkonium production in proton-proton, proton-nucleus and nucleus-nucleus
collisions. This includes discussion of the effects of hot and cold strongly
interacting matter, quarkonium photo-production in nucleus-nucleus collisions
and perspectives on the study of heavy flavour and quarkonium with upgrades of
existing experiments and new experiments. The report results from the activity
of the SaporeGravis network of the I3 Hadron Physics programme of the European
Union 7th Framework Programme
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