296 research outputs found
Imprint of chiral symmetry restoration on the Polyakov loop and the heavy quark free energy
The Polyakov loop expectation value is an order parameter
of the deconfinement transition in the heavy quark mass regime, whereas its
sensitivity to the deconfinement of light, dynamical quarks is not apparent.
From the perspective of an effective Lagrangian in the vicinity of the chiral
transition, the Polyakov loop, , is an energy-like observable, and should hence scale like the energy density. Using HISQ
configurations at finite lattice spacing, we show that near the chiral
transition temperature, the scaling behavior of and the
heavy quark free energy is consistent with energy-like observables in the
3-, O() universality class. We extend this analysis to other Polyakov
loop observables, including the response of the heavy quark free energy, ,
to the baryon chemical potential, which is expected to scale like a specific
heat.Comment: 10 pages, 3 figures, presented at the 38th International Symposium on
Lattice Field Theor
HotQCD on Multi-GPU Systems
We present , HotQCD's software for performing lattice
QCD calculations on GPUs. Started in late 2017 and intended as a full
replacement of the previous single GPU lattice QCD code used by the HotQCD
collaboration, our software has been developed into an extensive framework for
lattice QCD calculations distributed on multiple GPUs over many compute nodes.
The code is built on C++, CUDA, and MPI and leverages modern C++ language
features to provide high-level data structures, objects, and algorithms that
allow users to express lattice QCD calculations in an intuitive way without
sacrificing performance. Implemented algorithms range from gradient flow,
correlator measurements, and mixed precision conjugate gradient solvers all the
way to full HISQ gauge field configuration generation using RHMC. After
successful deployment in large-scale computing projects, we want to share the
result of our efforts with the lattice QCD community by making it publicly
available. In these proceedings, we will present some of the key features of
our code, demonstrate its ease of use, and show benchmarks of performance
critical kernels on state-of-the-art supercomputers.Comment: 7 pages, 3 figures, presented at the 38th International Symposium on
Lattice Field Theor
Lattice QCD Calculation for the Physical Equation of State
In this report we consider the numerical simulations at finite temperature
using lattice QCD data for the computation of the thermodynamical quantities
including the pressure, energy density and the entropy density. These physical
quantities can be related to the equation of state for quarks and gluons. We
shall apply the lattice data to the evaluation of the specific structure of the
gluon and quark condensates at finite temperature in relation to the
deconfinement and chiral phase transitions. Finally we mention the quantum
nature of the phases at lower temperatures.Comment: 60 pages, 15 figure
oxLDL Downregulates the Dendritic Cell Homing Factors CCR7 and CCL21
Introduction. Dendritic cells (DCs) and oxLDL play an important role in the atherosclerotic process with DCs accumulating in the plaques during plaque progression. Our aim was to investigate the role of oxLDL in the modulation of the DC homing-receptor CCR7 and endothelial-ligand CCL21. Methods and Results. The expression of the DC homing-receptor CCR7 and its endothelial-ligand CCL21 was examined on atherosclerotic carotic plaques of 47 patients via qRT-PCR and immunofluorescence. In vitro, we studied the expression of CCR7 on DCs and CCL21 on human microvascular endothelial cells (HMECs) in response to oxLDL. CCL21- and CCR7-mRNA levels were significantly downregulated in atherosclerotic plaques versus non-atherosclerotic controls [90% for CCL21 and 81% for CCR7 (P < 0.01)]. In vitro, oxLDL reduced CCR7 mRNA levels on DCs by 30% and protein levels by 46%. Furthermore, mRNA expression of CCL21 was significantly reduced by 50% (P < 0.05) and protein expression by 24% in HMECs by oxLDL (P < 0.05). Conclusions. The accumulation of DCs in atherosclerotic plaques appears to be related to a downregulation of chemokines and their ligands, which are known to regulate DC migration. oxLDL induces an in vitro downregulation of CCR7 and CCL21, which may play a role in the reduction of DC migration from the plaques
Serendipitous Discovery of PSR J1431-6328 as a Highly-Polarized Point Source with the Australian SKA Pathfinder
We identified a highly-polarized, steep-spectrum radio source in a deep image
with the Australian Square Kilometre Array Pathfinder (ASKAP) telescope at 888
MHz. After considering and rejecting a stellar origin for this source, we
discovered a new millisecond pulsar (MSP) using observations from the Parkes
radio telescope. This pulsar has period 2.77 ms and dispersion measure 228.27
pc/cm**3. Although this pulsar does not yet appear to be particularly
remarkable, the short spin period, wide profile and high dispersion measure do
make it relatively hard to discover through traditional blind periodicity
searches. Over the course of several weeks we see changes in the barycentric
period of this pulsar that are consistent with orbital motion in a binary
system, but the properties of any binary need to be confirmed by further
observations. While even a deep ASKAP survey may not identify large numbers of
new MSPs compared to the existing population, it would be competitive with
existing all-sky surveys and could discover interesting new MSPs at high
Galactic latitude without the need for computationally-expensive all-sky
periodicity searches.Comment: ApJ, in pres
AAV-Tau Mediates Pyramidal Neurodegeneration by Cell-Cycle Re-Entry without Neurofibrillary Tangle Formation in Wild-Type Mice
In Alzheimer's disease tauopathy is considered secondary to amyloid, and the duality obscures their relation and the definition of their respective contributions
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