69,714 research outputs found
Flow and non-flow correlations from four-particle multiplets in STAR
Elliptic flow results are presented for Au + Au collisions at
GeV in RHIC. This signal is investigated as a function of transverse
momentum, rapidity and centrality. Results from four-particle correlation
analysis, which can filter out contributions to the flow signal from
correlations unrelated to the event reaction plane (``non-flow''), are
presented and compared to the conventional method, in which non-flow effects
are treated as part of the systematic uncertainty.Comment: 5 pages, 4 figures, uses the class "aipproc
Quenched degrees of freedom in symmetric diblock copolymer thin films
We study the effect of monomer immobilization (quenching) on the orientation
of the lamellae in symmetric diblock copolymer thin films with neutrally
wetting surfaces. A small fraction of the monomers immediately next to the
solid substrate is presumed to be quenched. In both the weak segregation limit
and the strong segregation limit, quenching favors the lamellae orienting
perpendicular to the film. Quenching inhibits the order-disorder transition
twice as much for the parallel orientation as for the perpendicular.Comment: 11 page
To synchronize or not to synchronize, that is the question: finite-size scaling and fluctuation effects in the Kuramoto model
The entrainment transition of coupled random frequency oscillators presents a
long-standing problem in nonlinear physics. The onset of entrainment in
populations of large but finite size exhibits strong sensitivity to
fluctuations in the oscillator density at the synchronizing frequency. This is
the source for the unusual values assumed by the correlation size exponent
. Locally coupled oscillators on a -dimensional lattice exhibit two
types of frequency entrainment: symmetry-breaking at , and aggregation
of compact synchronized domains in three and four dimensions. Various critical
properties of the transition are well captured by finite-size scaling relations
with simple yet unconventional exponent values.Comment: 9 pages, 1 figure, to appear in a special issue of JSTAT dedicated to
Statphys2
Prevention of diabetes by FTY720-mediated stabilization of peri-islet tertiary lymphoid organs.
ObjectiveThe nonobese diabetic (NOD) mouse is a well-established mouse model of spontaneous type 1 diabetes, which is characterized by an autoimmune destruction of the insulin-secreting pancreatic beta-cells. In this study, we address the role of tertiary lymphoid organs (TLOs) that form in the pancreas of NOD mice during disease progression.MethodsWe developed a model designed to "lock" lymphocytes in the pancreatic lymph node (PLN) and pancreas by the use of FTY720, which blocks the exit of lymphocytes from lymph nodes. A combination of flow cytometry, immunofluorescence, and analysis of clinical scores was used to study the effects of long-term FTY720 treatment on TLO development and development of diabetes.ResultsContinuous treatment of NOD mice with FTY720 prevented diabetes development even at a time of significant insulitis. Treatment withdrawal led to accelerated disease independent of the PLN. Interestingly, naive T-cells trafficked to and proliferated in the TLOs. In addition, morphological changes were observed that occurred during the development of the disease. Remarkably, although the infiltrates are not organized into T/B-cell compartments in 8-week-old mice, by 20 weeks of age, and in age-matched mice undergoing FTY720 treatment, the infiltrates showed a high degree of organization. However, in naturally and FTY720-induced diabetic mice, T/B-cell compartmentalization was lost.ConclusionOur data show that TLOs are established during diabetes development and suggest that islet destruction is due to a loss of TLO integrity, which may be prevented by FTY720 treatment
Origin of the roughness exponent in elastic strings at the depinning threshold
Within a recently developed framework of dynamical Monte Carlo algorithms, we
compute the roughness exponent of driven elastic strings at the
depinning threshold in 1+1 dimensions for different functional forms of the
(short-range) elastic energy. A purely harmonic elastic energy leads to an
unphysical value for . We include supplementary terms in the elastic
energy of at least quartic order in the local extension. We then find a
roughness exponent of , which coincides with the one
obtained for different cellular automaton models of directed percolation
depinning. The quartic term translates into a nonlinear piece which changes the
roughness exponent in the corresponding continuum equation of motion. We
discuss the implications of our analysis for higher-dimensional elastic
manifolds in disordered media.Comment: 4 pages, 2 figure
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