367 research outputs found
Enumerative Theory for the Tsetlin Library
The Tsetlin library is a well-studied Markov chain on the symmetric group
. It has stationary distribution the Luce model, a
nonuniform distribution on , which appears in psychology, horse race
betting, and tournament poker. Simple enumerative questions, such as ``what is
the distribution of the top cards?'' or ``what is the distribution of the
bottom cards?'' are long open. We settle these questions and draw attention
to a host of parallel questions on the extension to the chambers of a
hyperplane arrangement.Comment: 23 pages, 1 figur
Smoluchowski dynamics and the ergodic-nonergodic transition
We use the recently introduced theory for the kinetics of systems of
classical particles to investigate systems driven by Smoluchowski dynamics. We
investigate the existence of ergodic-nonergodic (ENE) transitions near the
liquid-glass transition. We develop a self-consistent perturbation theory in
terms of an effective two-body potential. We work to second order in this
potential. At second order we have an explicit relationship between the static
structure factor and the effective potential. We choose the static structure
factor in the case of hard spheres to be given by the solution of the
Percus-Yevick approximation for hard spheres. Then using the analytically
determined ENE equation for the ergodicity function we find an ENE transition
for packing fraction, eta, greater than a critical value eta*=0.76 which is
physically unaccessible. The existence of a linear fluctuation-dissipation
theorem in the problem is shown and used to great advantage.Comment: 51 pages, 6 figure
Granular clustering in a hydrodynamic simulation
We present a numerical simulation of a granular material using hydrodynamic
equations. We show that, in the absence of external forces, such a system
phase-separates into high density and low density regions. We show that this
separation is dependent on the inelasticity of collisions, and comment on the
mechanism for this clustering behavior. Our results are compatible with the
granular clustering seen in experiments and molecular dynamic simulations of
inelastic hard disks.Comment: 4 pages, 5 figure
Bone regeneration at extraction sockets filled with leukocyte-platelet-rich fibrin:an experimental pre-clinical study
We aimed to histomorphometrically evaluate the effects of Leucocyte-Platelet-Rich Fibrin (L-PRF), with and without the combination of a bone grafting material, for alveolar ridge preservation using an in vivo canine model. Seven dogs (Female Beagles, ~18-month-old) were acquired for the study. L-PRF was prepared from each individual animal by drawing venous blood and spinning them through a centrifuge at 408 RCF-clot (IntrasSpin, Intra-Lock, Boca Raton, FL). L-PRF membranes were obtained from XPression fabrication kit (Biohorizons Implant Systems, Inc., AL, USA). A split mouth approach was adopted with the first molar mesial and distal socket defects treated in an interpolated fashion of the following study groups: 1) Empty socket (negative control); 2) OSS filled defect 3) L-PRF membrane; and 4) Mix of Bio-OssĀ® with L-PRF. After six weeks, samples were harvested, histologically processed, and evaluated for bone area fraction occupancy (BAFO), vertical/horizontal ridge dimensions (VRD and HRD, respectively), and area of coronal soft tissue infiltration. BAFO was statistically lower for the control group in comparison to all treatment groups. Defects treated with Bio-OssĀ® were not statistically different then defects treated solely with L-PRF. Collapsed across all groups, L-PRF exhibited higher degrees of BAFO than groups without L-PRF. Defects filled with Bio-OssĀ® and Bio-OssĀ® with L-PRF demonstrated greater maintenance of VRD relative to the control group. Collapsed across all groups, Bio-OssĀ® maintained the VRD and resulted in less area of coronal soft tissue infiltration compared to the empty defect. Soft tissue infiltration observed at the coronal area was not statistically different among defects filled with L-PRF, Bio-OssĀ®, and Bio-OssĀ® with L-PRF. Inclusion of L-PRF to particulate xenograft did not promote additional bone heading at 6 weeks in vivo. However, we noted that L-PRF alone promoted alveolar socket regeneration to levels comparable to particulate xenografts, suggesting its potential utilization for socket preservation
Model for Glass Transition in a Binary fluid from a Mode Coupling approach
We consider the Mode Coupling Theory (MCT) of Glass transition for a Binary
fluid. The Equations of Nonlinear Fluctuating Hydrodynamics are obtained with a
proper choice of the slow variables corresponding to the conservation laws. The
resulting model equations are solved in the long time limit to locate the
dynamic transition. The transition point from our model is considerably higher
than predicted in existing MCT models for binary systems. This is in agreement
with what is seen in Computer Simulation of binary fluids. fluids.Comment: 9 Pages, 3 Figure
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