Return to return point memory

We describe a new class of systems exhibiting return point memory (RPM) that are different from those discussed before in the context of ferromagnets. We show numerically that one dimensional random Ising antiferromagnets have RPM, when configurations evolve from a large field. However, RPM is violated when started from some stable configurations at finite field unlike in the ferromagnetic case. This implies that the standard approach to understanding ferromagnetic RPM systems will fail for this case. We also demonstrate RPM with a set of variables that keep track of spin flips at each site. Conventional RPM for the spin configuration is a projection of this result, suggesting that spin flip variables might be a more fundamental representation of the dynamics. We also present a mapping that embeds the antiferromagnetic chain in a two dimensional ferromagnetic model, and prove RPM for spin exchange dynamics in the interior of the chain with this mapping

Nonconcentration of return times

We show that the distribution of the first return time $\tau$ to the origin, v, of a simple random walk on an infinite recurrent graph is heavy tailed and nonconcentrated. More precisely, if $d_v$ is the degree of v, then for any $t\geq1$ we have $$\mathbf{P}_v(\tau\ge t)\ge\frac{c}{d_v\sqrt{t}}$$ and $$\mathbf{P}_v(\tau=t\mid\tau\geq t)\leq\frac{C\log(d_vt)}{t}$$ for some universal constants $c>0$ and $C<\infty$. The first bound is attained for all t when the underlying graph is $\mathbb{Z}$, and as for the second bound, we construct an example of a recurrent graph G for which it is attained for infinitely many t's. Furthermore, we show that in the comb product of that graph G with $\mathbb{Z}$, two independent random walks collide infinitely many times almost surely. This answers negatively a question of Krishnapur and Peres [Electron. Commun. Probab. 9 (2004) 72-81] who asked whether every comb product of two infinite recurrent graphs has the finite collision property.Comment: Published in at http://dx.doi.org/10.1214/12-AOP785 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

ANALISIS PENGARUH RETURN ON ASSETS (ROA), RETURN ON EQUITY (ROE) DAN NET PROFIT MARGIN (NPM) TERHADAP RETURN SAHAM PADA PERUSAHAAN MANUFAKTUR YANG TERDAFTAR DI BURSA EFEK INDONESIA

Title "The Analysis Return on assets (ROA), return on equity (ROE), net profit margin (NPM) of the return on the stock of manufacturing companies listed in Indonesia Stock Exchange." This research aims to influence the performance tester manufacturing company (ROA, ROE, and NPM) of the shares and return of these three variables (ROA, ROE, and NPM) where the most significant return to shareholders registered at the Indonesian Stock Exchange. In this research, data analysis technique that is used is to perform calculations find ROA, ROE, NPM, stock return from year 2005,2006,2007, perform statistical testing, test the assumption of classical regression analysis and berganda. Research results indicate that simultaneously calculated F = 0.609 less than the F table = 3.80 means ROA, ROE, and NPM does not affect the stock return. And that the partial calculating ROA T = 0.899 T is less than the table means = 1.77 ROA does not affect the stock return. ROE calculated T = -0.437 is less than the table T = 1.77 does not mean ROE barpangaruh return to shareholders. NPM calculated T = -1.123 is less than Q = 1.77 means that the table NPM does not affect the stock return. This condition indicates that the ROA, ROE and NPM has contributed to a low return on shar

Return to Battleship Island

No abstract available

Hydrogen Balmer line formation in solar flares affected by return currents

Aims. We investigate the effect of the electric return currents in solar flares on the profiles of hydrogen Balmer lines. We consider the monoenergetic approximation for the primary beam and runaway model of the neutralizing return current. Methods. Propagation of the 10 keV electron beam from a coronal reconnection site is considered for the semiempirical chromosphere model F1. We estimate the local number density of return current using two approximations for beam energy fluxes between $4\times 10^{11}$ and $1\times 10^{12} {\rm erg cm^{-2} s^{-1}}$. Inelastic collisions of beam and return-current electrons with hydrogen are included according to their energy distributions, and the hydrogen Balmer line intensities are computed using an NLTE radiative transfer approach. Results. In comparison to traditional NLTE models of solar flares that neglect the return-current effects, we found a significant increase emission in the Balmer line cores due to nonthermal excitation by return current. Contrary to the model without return current, the line shapes are sensitive to a beam flux. It is the result of variation in the return-current energy that is close to the hydrogen excitation thresholds and the density of return-current electrons.Comment: 4 pages, 3 figures, 1 table, accepted for publication in Astronomy and Astrophysics Letter