1,176 research outputs found
Quark Matter 2006: high-pT and jets
An overview of new experimental results on high-\pT{} particle production and
jets in heavy ion collisions from the Quark Matter 2006 conference is
presented.Comment: Presented at Quark Matter 200
Thermal energy budget of electrons in the inner heliosphere: Parker Solar Probe Observations
We present an observational analysis of the electron thermal energy budget
using data from Parker Solar Probe. We use the macroscopic moments, obtained
from our fits to the measured electron distribution function, to evaluate the
thermal energy budget based on the second moment of the Boltzmann equation. We
separate contributions to the overall budget from reversible and irreversible
processes. We find that a thermal-energy source must be present in the inner
heliosphere over the heliocentric distance range from 0.15 to 0.47 au. The
divergence of the heat flux is positive at heliocentric distances below 0.33
au, while beyond 0.33 au, there is a measurable degradation of the heat flux.
Expansion effects dominate the thermal energy budget below 0.3 au. Under our
steady-state assumption, the free streaming of the electrons is not sufficient
to explain the thermal energy density budget. We conjecture that the most
likely driver for the required heating process is turbulence. Our results are
consistent with the known non-adiabatic polytropic index of the electrons,
which we measure as 1.176 in the explored range of heliocentric distances.Comment: Paper accepted to The Astrophysical Journa
Heavy-Quark Diffusion, Flow and Recombination at RHIC
We discuss recent developments in assessing heavy-quark interaction in the
Quark-Gluon Plasma (QGP). While induced gluon radiation is expected to be the
main energy-loss mechanism for fast-moving quarks, we focus on elastic
scattering which prevails toward lower energies, evaluating both perturbative
(gluon-exchange) and nonperturbative (resonance formation) interactions in the
QGP. The latter are treated within an effective model for D- and B-meson
resonances above T_c as motivated by current QCD lattice calculations.
Pertinent diffusion and drag constants, following from a Fokker-Planck
equation, are implemented into an expanding fireball model for Au-Au collisions
at RHIC using relativistic Langevin simulations. Heavy quarks are hadronized in
a combined fragmentation and coalescence framework, and resulting
electron-decay spectra are compared to recent RHIC data. A reasonable
description of both nuclear suppression factors and elliptic flow up to momenta
of ~5 GeV supports the notion of a strongly interacting QGP created at RHIC.
Consequences and further tests of the proposed resonance interactions are
discussed.Comment: 8 pages, 14 figures, contribution to the proceedings for the
"International Conference on Strangeness in Quark Matter 2006
Non-Equilibrium in Adsorbed Polymer Layers
High molecular weight polymer solutions have a powerful tendency to deposit
adsorbed layers when exposed to even mildly attractive surfaces. The
equilibrium properties of these dense interfacial layers have been extensively
studied theoretically. A large body of experimental evidence, however,
indicates that non-equilibrium effects are dominant whenever monomer-surface
sticking energies are somewhat larger than kT, a common case. Polymer
relaxation kinetics within the layer are then severely retarded, leading to
non-equilibrium layers whose structure and dynamics depend on adsorption
kinetics and layer ageing. Here we review experimental and theoretical work
exploring these non-equilibrium effects, with emphasis on recent developments.
The discussion addresses the structure and dynamics in non-equilibrium polymer
layers adsorbed from dilute polymer solutions and from polymer melts and more
concentrated solutions. Two distinct classes of behaviour arise, depending on
whether physisorption or chemisorption is involved. A given adsorbed chain
belonging to the layer has a certain fraction of its monomers bound to the
surface, f, and the remainder belonging to loops making bulk excursions. A
natural classification scheme for layers adsorbed from solution is the
distribution of single chain f values, P(f), which may hold the key to
quantifying the degree of irreversibility in adsorbed polymer layers. Here we
calculate P(f) for equilibrium layers; we find its form is very different to
the theoretical P(f) for non-equilibrium layers which are predicted to have
infinitely many statistical classes of chain. Experimental measurements of P(f)
are compared to these theoretical predictions.Comment: 29 pages, Submitted to J. Phys.: Condens. Matte
RHIC physics overview
The results from data taken during the last several years at the Relativistic
Heavy-Ion Collider (RHIC) will be reviewed in the paper. Several selected
topics that further our understanding of constituent quark scaling, jet
quenching and color screening effect of heavy quarkonia in the hot dense medium
will be presented. Detector upgrades will further probe the properties of Quark
Gluon Plasma. Future measurements with upgraded detectors will be presented.
The discovery perspectives from future measurements will also be discussed.Comment: 9 pages, 4 figures, invited review article, published by Frontier of
Physics in Chin
Efficacy and safety of mavrilimumab in giant cell arteritis: a phase 2, randomised, double-blind, placebo-controlled trial
OBJECTIVES: Granulocyte-macrophage colony-stimulating factor (GM-CSF) is implicated in pathogenesis of giant cell arteritis. We evaluated the efficacy of the GM-CSF receptor antagonist mavrilimumab in maintaining disease remission. METHODS: This phase 2, double-blind, placebo-controlled trial enrolled patients with biopsy-confirmed or imaging-confirmed giant cell arteritis in 50 centres (North America, Europe, Australia). Active disease within 6 weeks of baseline was required for inclusion. Patients in glucocorticoid-induced remission were randomly assigned (3:2 ratio) to mavrilimumab 150 mg or placebo injected subcutaneously every 2 weeks. Both groups received a 26-week prednisone taper. The primary outcome was time to adjudicated flare by week 26. A prespecified secondary efficacy outcome was sustained remission at week 26 by Kaplan-Meier estimation. Safety was also assessed. RESULTS: Of 42 mavrilimumab recipients, flare occurred in 19% (n=8). Of 28 placebo recipients, flare occurred in 46% (n=13). Median time to flare (primary outcome) was 25.1 weeks in the placebo group, but the median was not reached in the mavrilimumab group (HR 0.38; 95% CI 0.15 to 0.92; p=0.026). Sustained remission at week 26 was 83% for mavrilimumab and 50% for placebo recipients (p=0.0038). Adverse events occurred in 78.6% (n=33) of mavrilimumab and 89.3% (n=25) of placebo recipients. No deaths or vision loss occurred in either group. CONCLUSIONS: Mavrilimumab plus 26 weeks of prednisone was superior to placebo plus 26 weeks of prednisone for time to flare by week 26 and sustained remission in patients with giant cell arteritis. Longer treatment is needed to determine response durability and quantify the glucocorticoid-sparing potential of mavrilimumab. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov number: NCT03827018, Europe (EUdraCT number: 2018-001003-36), and Australia (CT-2018-CTN-01 865-1)
Jet Quenching in Heavy Ion Collisions
This review article was prepared for the Landolt-Boernstein volume on
Relativisitc Heavy Ion Physics.Comment: Review articel accepted for publication in the Landolt-Boernstein
Handbook of Physics, ed. R. Stock. 41 pages LaTex, 7 eps-figure
Return to Play After Isolated Meniscal Repairs in Athletes: A Systematic Review.
Background: Meniscal tears are a common knee injury. Isolated meniscal tears are less common; however, unaddressed tears can be troublesome, particularly for athletes. There is currently a lack of data in the literature on athletes returning to play after isolated meniscal repair.
Purpose: To evaluate the return to play rate and time to return to play for athletes with isolated meniscal injuries.
Study Design: Systematic review; Level of evidence, 4.
Methods: A search of the PubMed, EMBASE, and Cochrane electronic databases was conducted to identify studies that reported the time and the rate of return to play in athletes after repair of isolated meniscal tears. Studies were excluded if there was a concomitant anterior cruciate ligament reconstruction, if there was a meniscectomy instead of a meniscal repair, or if the study was a systematic review. Quality assessment and data extraction were performed by 2 examiners.
Results: Overall, 21 studies were included in this review. There were 355 athletes (358 knees) with a mean age of 22.5 years (range, 9-68 years). A sex breakdown was noted in 16 of the 21 (76.2%) studies with 224 men and 71 women. The specific repair technique was described in 259 (72.3%) knees. Of the total knees, 109 (30.4%) had an open repair, 128 (35.8%) had an inside-out arthroscopic technique repair, and 22 (6.1%) had an all-inside arthroscopic technique repair. Complications were addressed in 11 studies, with 13 out of 155 (8.4%) patients across the 11 articles having a postoperative complication. Of the total 355 patients, 295 (83.1%) returned to play, and 17 of these 21 (81.0%) articles reported the time it took for athletes to return to play, with a mean return of 8.7 months.
Conclusion: The study results indicate that return to play rates after isolated meniscal repair are high, with an overall return to play rate of 83.1% and a mean return to play time of 8.7 months. However, the limited number of studies, particularly ones with larger patient numbers, highlights the need for further investigation regarding isolated meniscal repair in athletes
Mach Cones in Quark Gluon Plasma
The experimental azimuthal dihadron distributions at RHIC show a double peak
structure in the away side ( rad.) for intermediate
particles. A variety of models have appeared trying to describe this
modification. We will review most of them, with special emphasis in the Conical
Flow scenario in which the observed shape is a consequence of the emission of
sound by a supersonic high momentum particle propagating in the Quark Gluon
Plasma.Comment: 8 pages, 3 figures, Invited plenary talk given at the 19th
International Conference on Ultrarelativistic Nucleus-Nucleus Collisions:
Quark Matter 2006 (QM 2006), Shanghai, China, 14-20 Nov 200
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