Fluctuation Formula in the Nose-Hoover thermostated Lorentz gas

In this paper we examine numerically the Gallavotti-Cohen fluctuation formula for phase-space contraction rate and entropy production rate fluctuations in the Nos\'e-Hoover thermostated periodic Lorentz gas. Our results indicate that while the phase-space contraction rate fluctuations violate the fluctuation formula near equilibrium states, the entropy production rate fluctuations obey this formula near and far from equilibrium states as well.Comment: 4 pages, 8 figure

Monte Carlo simulation of the electrical properties of electrolytes adsorbed in charged slit-systems

We study the adsorption of primitive model electrolytes into a layered slit system using grand canonical Monte Carlo simulations. The slit system contains a series of charged membranes. The ions are forbidden from the membranes, while they are allowed to be adsorbed into the slits between the membranes. We focus on the electrical properties of the slit system. We show concentration, charge, electric field, and electrical potential profiles. We show that the potential difference between the slit system and the bulk phase is mainly due to the double layers formed at the boundaries of the slit system, but polarization of external slits also contributes to the potential drop. We demonstrate that the electrical work necessary to bring an ion into the slit system can be studied only if we simulate the slit together with the bulk phases in one single simulation cell.Comment: 11 pages, 8 figure

Compressive load bearing and bone architecture of lumbar vertebrae in terms of sex and aging

Relation between vertebral compressive strength and trabecular architecture is presented in terms of aging and sex. Complex in vitro medical-engineering analysis of cadaver human lumbar L1 and L2 vertebrae was executed: densitometry, CT, MRI, mechanical test and histology, in aspect of osteoporosis. In this paper the results of the mechanical test are detailed only. The compressive mechanical parameters, like limit stress and strain, proportional stress and strain, Young modulus, ductility, energy absorption capacity were determined. Morphometry analysis was based on the CT pictures. Density and diameter of trabeculae were measured. Correlation between morphometric and mechanical properties was evaluated in terms of aging, sex and bone mineral density

Determinants of Real Exchange Rate Fluctuations in Hungary

This paper investigates the different sources of real exchange rate fluctuations in Hungary. We consider the effect of tradable pricing behavior and nominal rigidities in tradable real-exchange rate movements, and investigate the importance of relative productivity changes between the tradable and nontradable sector in relative price (nontradable/tradable) adjustments. We formulate a policy reaction function to separate the effect of tradable pricing shocks from policy shocks. The framework we use is a two sector open economy real exchange rate model. Its contemporaneous structure is used for the identification of structural shocks. Since the effect of policy shocks on tradable real exchange rate was not significant, our results suggest that nominal rigidities did not play an important role during the period under consideration. The evolution of nontradable prices and relative (nontradable/tradable) prices were well explained by nontradable output shocks. Thus, the Balassa-Samuelson-effect seems to have been at work in Hungary during the first eight years of transition.

Scanamorphos: a map-making software for Herschel and similar scanning bolometer arrays

Scanamorphos is one of the public softwares available to post-process scan observations performed with the Herschel photometer arrays. This post-processing mainly consists in subtracting the total low-frequency noise (both its thermal and non-thermal components), masking high-frequency artefacts such as cosmic ray hits, and projecting the data onto a map. Although it was developed for Herschel, it is also applicable with minimal adjustment to scan observations made with some other imaging arrays subjected to low-frequency noise, provided they entail sufficient redundancy; it was successfully applied to P-Artemis, an instrument operating on the APEX telescope. Contrary to matrix-inversion softwares and high-pass filters, Scanamorphos does not assume any particular noise model, and does not apply any Fourier-space filtering to the data, but is an empirical tool using purely the redundancy built in the observations -- taking advantage of the fact that each portion of the sky is sampled at multiple times by multiple bolometers. It is an interactive software in the sense that the user is allowed to optionally visualize and control results at each intermediate step, but the processing is fully automated. This paper describes the principles and algorithm of Scanamorphos and presents several examples of application.Comment: This is the final version as accepted by PASP (on July 27, 2013). A copy with much better-quality figures is available on http://www2.iap.fr/users/roussel/herschel

Hungary in the NIGEM model

This paper presents a nationwide economy model for Hungary used by the National Bank of Hungary for analyzing the effects of world shocks, for quarterly forecasting exercises and other policy simulations. The study has two main goals: Firstly, we present the model for the Hungarian economy, developed in collaboration between the National Bank of Hungary and the National Institute of Economic and Social Research. The model is a one-sector aggregate economy model with a theoretically consistent supply side. A particular role is given to foreign direct investments in explaining the sources of growth both in the production process and foreign trade. Secondly, there is a brief discussion of the National Institute’s Global Econometric Model (NIGEM), to which the Hungarian model is linked. In this setup, we are also able to analyze the effect of world shocks on the domestic economy. For testing model properties, we present policy simulations for various shocks. A case study on the effect of the Russian crisis on Hungary is also discussed for the purpose of testing parameter adequacy.

Boundary Conditions for Fractional Diffusion

This paper derives physically meaningful boundary conditions for fractional diffusion equations, using a mass balance approach. Numerical solutions are presented, and theoretical properties are reviewed, including well-posedness and steady state solutions. Absorbing and reflecting boundary conditions are considered, and illustrated through several examples. Reflecting boundary conditions involve fractional derivatives. The Caputo fractional derivative is shown to be unsuitable for modeling fractional diffusion, since the resulting boundary value problem is not positivity preserving

How Far has Trade Integration Advanced? An analysis of actual and potential trade of three Central and Eastern European countries

This paper investigates the trade integration of three Central and Eastern European countries, namely the Czech Republic, Hungary and Poland, using the gravity model for trade as an analytical device. Beside the usual variables in such a model, we have also incorporated the FDI variables. According to our results, in the context of the most important Western European relations, it is Hungary that achieved the highest level of integration. Czech exports have also integrated, but there is still a very considerable potential there. Poland has integrated in exports to a much smaller extent than in imports. CEFTA-oriented trade has also gone up considerably, although the level of actual trade has not yet reached its full potential, except in the Czech Republic. Vis-a-vis South-East Asia, we have found overintegration for imports, but could see no signs of convergence for export towards this region. Our estimates support the trade-enhancing role of bilateral FDI. Paradoxically, the potential trade of the three countries estimated with FDI variables appears to be less than that suggested by the basic setup of the gravity model. We formulated two hypotheses to explain this, and supported one by a probit model. Finally, we tested for convergence and found that actual data indeed converged toward the estimated trade potential.

Forecasting Hungarian Export Volume

The paper summarizes the research on forecasting the Hungarian export volume. We elaborated a two-step procedure. In the first step we forecasted foreign demand, then in the second step we forecasted Hungarian export using the best outcome of the first step together with real exchange rate and import series. We used several econometric techniques and tested our results statistically by two criteria. We compared the precision and stability of the different forecasts. The ARIMA forecasts were employed as a benchmark. We found that in terms of both criteria foreign demand forecasts were significantly better than those obtained with ARIMA. However, in the case of the Hungarian export volume our results were only better in terms of the stability properties. Therefore the choice between the different forecasting methods was not obvious, so a ’Consensus’ index was also computed as a weighted average of different forecasts, where the weights were negative functions of imprecision and instability.