Nonlinear perturbations of Reissner-Nordstr\"om black holes

We develop a nonlinear perturbation theory of Reissner-Nordstr\"om black holes. We show that, at each perturbation level, Einstein-Maxwell equations can be reduced to four inhomogeneous wave equations, two for polar and two for axial sector. Gravitational part of these equations is similar to Regge-Wheeler and Zerilli equations with source and additional coupling to the electromagnetic sector. We construct solutions to the inhomogeneous part of wave equations in terms of sources for Einstein-Maxwell equations. We discuss $\ell=0$ and $\ell=1$ cases separately.Comment: 9 page

Transition Radiation Emitted from a Surface Irregularity Shaped as Rectangular Step and Rectangular Groove

Transition radiation emitted when a nonrelativistic particle (β=0.2-0.5) enters a surface irregularity shaped as a rectangular step and a rectangular groove and having the dielectric constant ε=1.4-3.8 has been investigated. The angular distribution of the radiation intensity as well as its dependence on the height of the irregularities, the width of the groove and the distance between the irregularity edge and the entry point of the particle have been calculated on the basis of the theory of Bagiyan and Ter-Mikaelyan.Zadanie pt. Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej naukę

Student Teaching and Research Laboratory Focusing on Brain-computer Interface Paradigms - A Creative Environment for Computer Science Students -

This paper presents an applied concept of a brain-computer interface (BCI) student research laboratory (BCI-LAB) at the Life Science Center of TARA, University of Tsukuba, Japan. Several successful case studies of the student projects are reviewed together with the BCI Research Award 2014 winner case. The BCI-LAB design and project-based teaching philosophy is also explained. Future teaching and research directions summarize the review.Comment: 4 pages, 4 figures, accepted for EMBC 2015, IEEE copyrigh

Labor market developments during economic transition

The paper reviews labor market developments in the transition economies of Europe and Central Asia. It argues that the scarcity of productive job opportunities and the growing labor market segmentation are the two main labor market problems facing the transition economies. In the European transition economies thelack of jobs has led to persistent open unemployment. In the Commonwealth of Independent States (CIS) it has led to hidden unemployment (underemployment and low productivity employment). Unemployment in the European transition economies is supported by the developed social safety net. In contrast, in the CIS for most workers unemployment is not an affordable option. They either stick to their old, unproductive jobs in unrestructured enterprises, or work in the informal sector, or resort to subsistence agriculture. Thus, underemployment in the CIS is a mirror image of unemployment in the European transition economies. Accordingly, the high employment-to-population ratios in many CIS countries do not necessarily signify favorable labor market performance. Instead they often indicate delayed enterprise restructuring, the maintenance of unsustainable jobs in uncompetitive firms, and the existence of a large informal sector as an employer of last resort. Labor market segmentation has been caused by a sharp increase in earnings differentials and the attendant increase in the incidence of low-paid jobs, by the polarization of regional labor market conditions, and finally by the growth of the informal sector offering casual, low-productivity jobs. Labor market segmentation and accompanying inequalities are more pronounced in the CIS than in the European transition economies.Labor Markets,Labor Standards,Labor Management and Relations,Educational Policy and Planning,Work&Working Conditions

Arbitrage Pricing of Multi-person Game Contingent Claims

We introduce a class of financial contracts involving several parties by extending the notion of a two-person game option (see Kifer (2000)) to a contract in which an arbitrary number of parties is involved and each of them is allowed to make a wide array of decisions at any time, not restricted to simply `exercising the option'. The collection of decisions by all parties then determines the contract's settlement date as well as the terminal payoff for each party. We provide sufficient conditions under which a multi-person game option has a unique arbitrage price, which is additive with respect to any partition of the contract