V473 Lyrae, a unique second-overtone Cepheid with two modulation cycles

V473 Lyrae is the only Galactic Cepheid with confirmed periodic amplitude and phase variations similar to the Blazhko effect observed in RR Lyrae stars. We collected all available photometric data and some radial velocity measurements to investigate the nature of the modulation. The comparison of the photometric and radial velocity amplitudes confirmed that the star pulsates in the second overtone. The extensive data set, spanning more than 40 years, allowed us to detect a secondary modulation cycle with a period of approximately 5300 days or 14.5 years. The secondary variations can be detected in the period of the primary modulation, as well. Phenomenologically, the light variations are analogous to the Blazhko effect. To find a physical link, we calculated linear hydrodynamic models to search for potential mode resonances that could drive the modulation and found two viable half-integer (n:2) and three n:4 resonances between the second overtone and other modes. If any of these resonances will be confirmed by non-linear models, it may confirm the mode resonance model, a common mechanism that can drive modulations both in RR Lyrae and Cepheid stars.Comment: 14 pages, 15 figures, accepted in MNRA

Variable stars with the Kepler space telescope

The Kepler space telescope has revolutionised our knowledge about exoplanets and stars and is continuing to do so in the K2 mission. The exquisite photometric precision, together with the long, uninterrupted observations opened up a new way to investigate the structure and evolution of stars. Asteroseismology, the study of stellar oscillations, allowed us to investigate solar-like stars and to peer into the insides of red giants and massive stars. But many discoveries have been made about classical variable stars too, ranging from pulsators like Cepheids and RR Lyraes to eclipsing binary stars and cataclysmic variables, and even supernovae. In this review, which is far from an exhaustive summary of all results obtained with Kepler, we collected some of the most interesting discoveries, and ponder on the role for amateur observers in this golden era of stellar astrophysics.Comment: 12 pages, 6 figures, published in the Journal of the AAVSO: https://www.aavso.org/apps/jaavso/article/3235/, v2: fixed a bad a reference. arXiv admin note: text overlap with arXiv:1108.3083 by other author

Analysis of the relationship among innovation performance, economic development and social welfare

In our modern world everything is related: without innovation performance there is no economic development, without economic development no improvement can be found in social welfare and vice versa. In this study I explore the relationship among these three key factors with the help of statistical methods. Before that I give a brief summary on the indices that makes the measurement of the above-mentioned fields possible. After that I carry out statistical description of these relationships by pairs with the method of correlation analysis. Results obtained on the basis of data of the European Union member states prove that relationships among innovation performance, economic development and social welfare of countries are very strong and statistically significant. Furthermore, analysis described in the paper also proves that increasing innovation performance has a positive effect on different dimensions of social welfare

Hajlítóin rekonstrukció aktív szilikon implantátummal = Renewal of human bending tendon implanting active silicone elastomer

A kutatás eredményeként kifejlesztésre került olyan szilikon hajlítóin implantátum, amely megközelíti a valós hajlítóin viselkedését. A kutatást kadaver inakon végzett szakítóvizsgálatok alapozták meg. A hajlítóin implantátumok prototípusgyártása előtt azok működését numerikus szimulációkkal ellenőriztem. Az implantátum hajlítómerevségét geometriai optimalizáció segítségével közelítettem a valós hajlítóin merevségéhez. Az implantátum húzómerevséget megfelelő szálerősítés alkalmazásával értem el. | As results of research were investigated such silicone tendon implants which mechanical behaviour reach the real tendon?s mechanical behaviour. Research based on mechanical testing (uniaxial tension tests) of cadaver tendons. Function of tendon implant was checked by numerical simulation which provided a very powerful tool to find the adequate shape of silicone tendon implant. Using simulation it was successful to increase the bending stiffness of tendon implant toward real tendon. Tension stiffness of implant was enhanced by using fibre reinforcing