1,276 research outputs found
Evidence for chemical equilibration at RHIC
This contribution focuses on the results of statistical model calculations at
RHIC energies, including recently available experimental data. Previous
calculations of particle yield ratios showed good agreement with measurements
at SPS and lower energies, suggesting that the composite system possesses a
high degree of chemical equilibrium at freeze-out. The effect of feeddown
contamination on the model parameters is discussed, and the sensitivity of
individual ratios to the model parameters (, ) is illustrated.Comment: Talk presented at Strange Quarks in Matter 2001, Frankfurt, September
24-29, 2001. Proceedings to be published by J. Phys. G. 8 pages with 4
figure
Strongly coupled matter near phase transition
In the Hartree approximation of Cornwall-Jackiw-Tomboulis (CJT) formalism of
the real scalar field theory, we show that for the strongly coupled scalar
system near phase transition, the shear viscosity over entropy density is
small, however, the bulk viscosity over entropy density is large. The large
bulk viscosity is related to the highly nonconformal equation of state. It is
found that the square of the sound velocity near phase transition is much
smaller than the conformal value 1/3, and the trace anomaly at phase transition
deviates far away from 0. These results agree well with the lattice results of
the complex QCD system near phase transition.Comment: 6 pages, 2 figures, 1 table, contributed to the International
Conference on Strangeness in Quark Matter 2008, Beijing, China, 6-10 October
200
Hadron Spectra and QGP Hadronization in Au+Au Collisions at RHIC
The transverse mass spectra of Omega hyperons and phi mesons measured
recently by STAR Collaboration in Au+Au collisions at sqrt(s_NN) = 130 GeV are
described within a hydrodynamic model of the quark gluon plasma expansion and
hadronization. The flow parameters at the plasma hadronization extracted by
fitting these data are used to predict the transverse mass spectra of J/psi and
psi' mesons.Comment: 4 pages, 4 figures, Fig. 3 correcte
Effect of Oral Iron Repletion on Exercise Capacity in Patients With Heart Failure With Reduced Ejection Fraction and Iron Deficiency: The IRONOUT HF Randomized Clinical Trial.
Importance: Iron deficiency is present in approximately 50% of patients with heart failure with reduced left ventricular ejection fraction (HFrEF) and is an independent predictor of reduced functional capacity and mortality. However, the efficacy of inexpensive readily available oral iron supplementation in heart failure is unknown.
Objective: To test whether therapy with oral iron improves peak exercise capacity in patients with HFrEF and iron deficiency.
Design, Setting, and Participants: Phase 2, double-blind, placebo-controlled randomized clinical trial of patients with HFrEF (
Interventions: Oral iron polysaccharide (n = 111) or placebo (n = 114), 150 mg twice daily for 16 weeks.
Main Outcomes and Measures: The primary end point was a change in peak oxygen uptake (V̇o2) from baseline to 16 weeks. Secondary end points were change in 6-minute walk distance, plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels, and health status as assessed by Kansas City Cardiomyopathy Questionnaire (KCCQ, range 0-100, higher scores reflect better quality of life).
Results: Among 225 randomized participants (median age, 63 years; 36% women) 203 completed the study. The median baseline peak V̇o2 was 1196 mL/min (interquartile range [IQR], 887-1448 mL/min) in the oral iron group and 1167 mL/min (IQR, 887-1449 mL/min) in the placebo group. The primary end point, change in peak V̇o2 at 16 weeks, did not significantly differ between the oral iron and placebo groups (+23 mL/min vs -2 mL/min; difference, 21 mL/min [95% CI, -34 to +76 mL/min]; P = .46). Similarly, at 16 weeks, there were no significant differences between treatment groups in changes in 6-minute walk distance (-13 m; 95% CI, -32 to 6 m), NT-proBNP levels (159; 95% CI, -280 to 599 pg/mL), or KCCQ score (1; 95% CI, -2.4 to 4.4), all P \u3e .05.
Conclusions and Relevance: Among participants with HFrEF with iron deficiency, high-dose oral iron did not improve exercise capacity over 16 weeks. These results do not support use of oral iron supplementation in patients with HFrEF.
Trial Registration: clinicaltrials.gov Identifier: NCT02188784
Design of a consensus-based geriatric assessment tailored for older chronic kidney disease patients:results of a pragmatic approach
PURPOSE: Unidentified cognitive decline and other geriatric impairments are prevalent in older patients with advanced chronic kidney disease (CKD). Despite guideline recommendation of geriatric evaluation, routine geriatric assessment is not common in these patients. While high burden of vascular disease and existing pre-dialysis care pathways mandate a tailored geriatric assessment, no consensus exists on which instruments are most suitable in this population to identify geriatric impairments. Therefore, the aim of this study was to propose a geriatric assessment, based on multidisciplinary consensus, to routinely identify major geriatric impairments in older people with advanced CKD. METHODS: A pragmatic approach was chosen, which included focus groups, literature review, inventory of current practices, an expert consensus meeting, and pilot testing. In preparation of the consensus meeting, we composed a project team and an expert panel (n = 33), drafted selection criteria for the selection of instruments, and assessed potential instruments for the geriatric assessment. RESULTS: Selection criteria related to general geriatric domains, clinical relevance, feasibility, and duration of the assessment. The consensus-assessment contains instruments in functional, cognitive, psychological, somatic, patient preferences, nutritional status, and social domains. Administration of (seven) patient questionnaires and (ten) professional-administered instruments, by nurse (practitioners), takes estimated 20 and 40 min, respectively. Results are discussed in a multidisciplinary meeting including at least nephrology and geriatric expertise, informing nephrology treatment decisions, and follow-up interventions among which comprehensive geriatric assessment. CONCLUSION: This first multidisciplinary consensus on nephrology-tailored geriatric assessment intent to benefit clinical care and enhance research comparability for older patients with advanced CKD
The Origin of Massive O-type Field Stars. Part II: Field O stars as runaways
In two papers we try to confirm that all Galactic high-mass stars are formed
in a cluster environment, by excluding that O-type stars found in the Galactic
field actually formed there. In de Wit et al. (2004) we presented deep K-band
imaging of 5 arcmin fields centred on 43 massive O-type field stars that
revealed that the large majority of these objects are single objects. In this
contribution we explore the possibility that the field O stars are dynamically
ejected from young clusters, by investigating their peculiar space velocity
distribution, their distance from the Galactic plane, and their spatial
vicinity to known young stellar clusters. We (re-)identify 22 field O-type
stars as candidate runaway OB-stars. The statistics show that ~4% of all O-type
stars with V < 8 can be considered as formed outside a cluster environment.
Most are spectroscopically single objects, some are visual binaries. The
derived percentage for O-type stars that form isolated in the field based on
our statistical analyses is in agreement with what is expected from
calculations adopting a universal cluster richness distribution with power
index of beta = 1.7, assuming that the cluster richness distribution is
continuous down to the smallest clusters containing one single star.Comment: 9 pages, 4 figures. Accepted for publication in A&
X Her and TX Psc: Two cases of ISM interaction with stellar winds observed by Herschel
The asymptotic giant branch (AGB) stars X Her and TX Psc have been imaged at
70 and 160 microns with the PACS instrument onboard the Herschel satellite, as
part of the large MESS (Mass loss of Evolved StarS) Guaranteed Time Key
Program. The images reveal an axisymmetric extended structure with its axis
oriented along the space motion of the stars. This extended structure is very
likely to be shaped by the interaction of the wind ejected by the AGB star with
the surrounding interstellar medium (ISM). As predicted by numerical
simulations, the detailed structure of the wind-ISM interface depends upon the
relative velocity between star+wind and the ISM, which is large for these two
stars (108 and 55 km/s for X Her and TX Psc, respectively). In both cases,
there is a compact blob upstream whose origin is not fully elucidated, but that
could be the signature of some instability in the wind-ISM shock. Deconvolved
images of X Her and TX Psc reveal several discrete structures along the
outermost filaments, which could be Kelvin-Helmholtz vortices. Finally, TX Psc
is surrounded by an almost circular ring (the signature of the termination
shock?) that contrasts with the outer, more structured filaments. A similar
inner circular structure seems to be present in X Her as well, albeit less
clearly.Comment: 11 pages, Astronomy & Astrophysics, in pres
Energy Spectra of Elemental Groups of Cosmic Rays: Update on the KASCADE Unfolding Analysis
The KASCADE experiment measures extensive air showers induced by cosmic rays
in the energy range around the so-called knee. The data of KASCADE have been
used in a composition analysis showing the knee at 3-5 PeV to be caused by a
steepening in the light-element spectra. Since the applied unfolding analysis
depends crucially on simulations of air showers, different high energy hadronic
interaction models (QGSJet and SIBYLL) were used. The results have shown a
strong dependence of the relative abundance of the individual mass groups on
the underlying model. In this update of the analysis we apply the unfolding
method with a different low energy interaction model (FLUKA instead of GHEISHA)
in the simulations. While the resulting individual mass group spectra do not
change significantly, the overall description of the measured data improves by
using the FLUKA model. In addition data in a larger range of zenith angle are
analysed. The new results are completely consistent, i.e. there is no hint to
any severe problem in applying the unfolding analysis method to KASCADE data.Comment: accepted for publication in Astroparticle Physic
Antideuteron yield at the AGS and coalescence implications
We present Experiment 864's measurement of invariant antideuteron yields in
11.5A GeV/c Au + Pt collisions. The analysis includes 250 million triggers
representing 14 billion 10% central interactions sampled for events with high
mass candidates. We find (1/2 pi pt) d^(2)N/dydpt = 3.5 +/- 1.5 (stat.)
+0.9,-0.5 (sys.) x 10^(-8) GeV^(-2)c^(2) for 1.8=0.35 GeV/c
(y(cm)=1.6) and 3.7 +/- 2.7 (stat.) +1.4,-1.5 (sys.) x 10^(-8) GeV^(-2)c^(2)
for 1.4=0.26 GeV/c, and a coalescence parameter B2-bar of 4.1 +/-
2.9 (stat.) +2.3,-2.4 (sys.) x 10^(-3) GeV^(2)c^(-3). Implications for the
coalescence model and antimatter annihilation are discussed.Comment: 8 pages, 4 figures, Latex, submitted to Phys. Rev. Let
Large scale cosmic-ray anisotropy with KASCADE
The results of an analysis of the large scale anisotropy of cosmic rays in
the PeV range are presented. The Rayleigh formalism is applied to the right
ascension distribution of extensive air showers measured by the KASCADE
experiment.The data set contains about 10^8 extensive air showers in the energy
range from 0.7 to 6 PeV. No hints for anisotropy are visible in the right
ascension distributions in this energy range. This accounts for all showers as
well as for subsets containing showers induced by predominantly light
respectively heavy primary particles. Upper flux limits for Rayleigh amplitudes
are determined to be between 10^-3 at 0.7 PeV and 10^-2 at 6 PeV primary
energy.Comment: accepted by The Astrophysical Journa
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