443 research outputs found
Event by event di-hadron correlations in Pb-Pb 2.76 TeV collisions from the ALICE experiment
The large multiplicities at the LHC may permit flow harmonics to be
determined on an event by event basis in Pb-Pb collisions. We extract these
harmonics from event by event di-hadron correlations. Within a fine centrality
bin, we find the correlation function varies substantially on an event by event
basis, indicating large fluctuations in the initial conditions for a given
impact parameter. Such large fluctuations lead to some events being highly
triangular or highly elliptical, where the angular correlation function is
completely dominated by the respective second and third Fourier harmonics. We
will show unfolded distributions for various centralities, and
implications for our understanding of the initial conditions.Comment: 4 pages, Hot Quarks 201
Untriggered di-hadron correlations in Pb-Pb collisions at 2.76 TeV from ALICE
We present measurements of untriggered di-hadron correlations as a function
of centrality in Pb-Pb \sNN collisions, for charged hadrons with
GeV. These measurements provide a map of the bulk correlation structures in
heavy-ion collisions. Contributions to these structures may come from jets,
initial density fluctuations, elliptic flow, resonances, and/or momentum
conservation. We decompose the measured correlation functions via a
multi-parameter fit in order to extract the nearside Gaussian, the longer range
correlation often referred to as the soft ridge. The effect of
including higher harmonics ( and ) in this procedure will be
discussed. We investigate how the nearside Gaussian scales with the number of
binary collisions. Finally, we show the charge dependence of the nearside
Gaussian.Comment: 4 pages, QM 2011 proceeding
The Centrality Dependence of Strange Baryon and Meson Production in Cu+Cu and Au+Au sqrt(s_NN) = 200 GeV collisions
Transverse momentum spectra of Lambda and K0Short particles are presented for
Cu+Cu sqrt(s_NN) = 200 GeV collisions observed at STAR, and compared to Au+Au
measurements at the same energy. For both systems, a number of observables are
shown to increase at mid-rapidity (|y| < 0.5) with increasing centrality. These
are the integrated Lambda and K0Short yields, the integrated Lambda and K0Short
yields per participating nucleon, and mid-pT (1 GeV/c -> 4.5 GeV/c)
Lambda/KK0Short ratios. The RCP ratio is found to be higher for the Lambda
yields at mid-pT compared to the K0Short yields for both the Cu+Cu and Au+Au
data. In contrast, when similar numbers of participating nucleons are
considered for the Cu+Cu and Au+Au data, an indication of increased bulk
strangeness production and a higher mid-pT (1 -> 4.5 GeV/c) Lambda/K0Short
ratio are found, for Cu+Cu.Comment: Quark Matter 2006 Proceeding
Strangeness Production in Heavy-Ion Collisions at STAR
We report an overview of strangeness production in Cu+Cu and Au+Au collisions
at the energies 62.4 and 200 GeV. We show new mid-rapidly
results for the , , , particles in
Cu+Cu \sNN{62} collisions and compare to results in Au+Au \sNN{62} collisions.
We show new results for mid- ratios in Cu+Cu \sNN{62}
collisions and again compare to ratios in Au+Au \sNN{62} collisions. Finally,
we show the high- ( GeV/c) as a function
of system size in Au+Au \sNN{200} collisions and compare to .Comment: 4 pages, 3 figures - To appear in the conference proceedings for
Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse
Strangeness production in jets from p+p \sqrt{s} = 200 GeV collisions
Measurements of strangeness production in jets help illuminate the QCD
mechanisms in fragmentation. Furthermore, they provide a crucial baseline for
heavy-ion studies where modifications in jet chemistry have recently been
predicted. We present new results on strange particle production in jets from
p+p \sqrt{s} = 200 GeV collisions measured by the STAR experiment. The momentum
distributions of the \Lambda, \bar{\Lambda} and K0Short particles are obtained
using various jet finding algorithms, and then compared to various models.
Strange particle ratios in jets are obtained and compared to values obtained
from the inclusive spectra. Finally, we show jets tagged with leading strange
baryons and mesons, in order to investigate whether gluon or quark jets can be
isolated in this way.Comment: 5 pages, 4 figures, Winter Workshop on Nuclear Dynamics 2010, Jamaic
Strange Particle Production at RHIC
We report STAR measurements of mid-rapidity yields for the ,
, , , , , and
particles in Cu+Cu and Au+Au GeV
collisions. We show that at a given number of participating nucleons, bulk
strangeness production is higher in Cu+Cu collisions compared to Au+Au
collisions at the same center of mass energy, counter to predictions from the
Canonical formalism. We compare both the Cu+Cu and Au+Au yields to AMPT and
EPOS predictions, and find they reproduce key qualitative aspects of the data.
Finally, we investigate other scaling parameters and find bulk strangeness
production for both the measured data and theoretical predictions, scales
better with the number participants that undergo more than one collision.Comment: Conference proceedings for Hot Quarks 2008, 5 pages and 4 figure
Overview of Strangeness Production at the STAR Experiment
We present an overview of recent STAR results on strangeness production in
p+p and heavy-ion collisions at RHIC. In both Cu+Cu and Au+Au collisions we
show the centrality dependencies of bulk yield and mid- spectrum
measurements with new comparisons to theory. The latest results for
strange particles are presented and prospects for strangeness production in the
low energy scan program will be outlined. Finally, we report new measurements
of strangeness fragmentation functions for jets in p+p collisions.Comment: 8 pages, 7 figures, proceedings for SQM 200
Can oral corticosteroids reduce the severity or duration of an acute cough, and the associated National Health Service and societal costs, in adults presenting to primary care?: study protocol for a randomised controlled trial
Background:
Acute lower respiratory tract infection (LRTI) is one of the most common conditions managed internationally and is costly to health services and patients. Despite good evidence that antibiotics are not effective for improving the symptoms of uncomplicated LRTI, they are widely prescribed, contributing to antimicrobial resistance. Many of the symptoms observed in LRTI are mediated by inflammatory processes also observed in exacerbations of asthma, for which there is strong evidence of corticosteroid effectiveness. The primary aim of the OSAC (Oral Steroids for Acute Cough) Trial is to determine whether oral prednisolone (40 mg daily for 5 days) can reduce the duration of moderately bad (or worse) cough and the severity of all its associated symptoms on days 2 to 4 post-randomisation (day 1 is trial entry) by at least 20% in adults ≥18 years with acute LRTI presenting to primary care.
Methods/design:
OSAC is a two-arm, multi-centre, placebo-controlled, randomised superiority trial. The target sample size is 436 patients, which allows for a 20% dropout rate. Patients will be recruited from primary care sites (General Practitioner surgeries) across England and followed up until symptom resolution. The two primary clinical outcomes are the duration of moderately bad (or worse) cough, and the severity of all its associated symptoms on days 2 to 4 post-randomisation. Secondary outcomes include: antibiotic consumption; symptom burden; adverse events; participant satisfaction with treatment and intention to consult for future similar illnesses. A parallel economic evaluation will investigate the cost-effectiveness of the intervention.
Discussion:
Results from the OSAC trial will increase knowledge regarding the clinical and cost-effectiveness of corticosteroids for LRTI, and will establish the potential of a new treatment option that could substantially improve patient health. We have chosen a relatively high ‘efficacy dose’ as this will enable us to decide on the potential for further research into lower dose oral and/or inhaled corticosteroids. This trial will also contribute to a growing body of research investigating the natural course of this very common illness, as well as the effects of steroids on the undesirable inflammatory symptoms associated with infection.
Trial registration:
Current Controlled Trials ISRCTN57309858 (31 January 2013)
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