Transplanted olfactory ensheathing cells promote regeneration of cut adult rat optic nerve axons

Transplantation of olfactory ensheathing cells into spinal cord lesions promotes regeneration of cut axons into terminal fields and functional recovery. This repair involves the formation of a peripheral nerve-like bridge in which perineurial-like fibroblasts are organized into a longitudinal stack of parallel tubular channels, some of which contain regenerating axons enwrapped by Schwann-like olfactory ensheathing cells. The present study examines whether cut retinal ganglion cell axons will also respond to these cells, and if so, whether they form the same type of arrangement. In adult rats, the optic nerve was completely severed behind the optic disc, and a matrix containing cultured olfactory ensheathing cells was inserted between the proximal and distal stumps. After 6 months, the transplanted cells had migrated for up to 10 mm into the distal stump. Anterograde labeling with cholera toxin B showed that cut retinal ganglion cell axons had regenerated through the transplants, entered the distal stump, and elongated for 10 mm together with the transplanted cells. Electron microscopy showed that a peripheral nerve-like tissue had been formed, similar to that seen in the spinal cord transplants. However, in contrast to the spinal cord, the axons did not reach the terminal fields, but terminated in large vesicle-filled expansions beyond which the distal optic nerve stump was reduced to a densely interwoven mass of astrocytic processes

Separating Solution of a Quadratic Recurrent Equation

In this paper we consider the recurrent equation $$\Lambda_{p+1}=\frac1p\sum_{q=1}^pf\bigg(\frac{q}{p+1}\bigg)\Lambda_{q}\Lambda_{p+1-q}$$ for $p\ge 1$ with $f\in C[0,1]$ and $\Lambda_1=y>0$ given. We give conditions on $f$ that guarantee the existence of $y^{(0)}$ such that the sequence $\Lambda_p$ with $\Lambda_1=y^{(0)}$ tends to a finite positive limit as $p\to \infty$.Comment: 13 pages, 6 figures, submitted to J. Stat. Phy

Effect of depreciation of the public goods in spatial public goods games

In this work, depreciated effect of the public goods is considered in the public goods games, which is realized by rescaling the multiplication factor r of each group as r' = r(nc/G)^beta (beat>= 0). It is assumed that each individual enjoys the full profit of the public goods if all the players of this group are cooperators, otherwise, the value of the public goods is reduced to r'. It is found that compared with the original version (beta = 0), emergence of cooperation is remarkably promoted for beta > 0, and there exit optimal values of beta inducing the best cooperation. Moreover, the optimal plat of beta broadens as r increases. Furthermore, effect of noise on the evolution of cooperation is studied, it is presented that variation of cooperator density with the noise is dependent of the value of beta and r, and cooperation dominates over most of the range of noise at an intermediate value of beta = 1.0. We study the initial distribution of the multiplication factor at beta = 1.0, and find that all the distributions can be described as Gauss distribution

Baryon enhancement in high-density QCD and relativistic heavy ion collisions

We argue that the collinear factorization of the fragmentation functions in high energy nuclear collisions breaks down at transverse momenta $p_T \lesssim Q_s/g$ due to high parton densities in the colliding hadrons and/or nuclei. We find that gluon recombination dominates in that $p_T$ region. We calculate the inclusive cross-section for $\pi$ meson and nucleon production using the low energy theorems for the scale anomaly in QCD, and compare our quantitative baryon-to-meson ratio to the RHIC data.Comment: 4 pages, 2 figure; Contribution to Quark Matter 2008 in Jaipur, India; submitted to J. Phys.

The Hahn Quantum System

Using a formulation of quantum mechanics based on the theory of orthogonal polynomials, we introduce a four-parameter system associated with the Hahn and continuous Hahn polynomials. The continuum energy scattering states are written in terms of the continuous Hahn polynomial whose asymptotics give the scattering amplitude and phase shift. On the other hand, the finite number of discrete bound states are associated with the Hahn polynomial.Comment: 18 pages, 7 figure