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No full textPoznańAn effect generated by the nonexponential behavior of the survival amplitude of an unstable state in the long time region is considered. We find that the instantaneous energy of the unstable state for a large class of models of unstable states tends to the minimal energy of the system E min as t → ∞ which is much smaller than the energy of this state for t of the order of the lifetime of the considered state. Analyzing the transition time region between the exponential and non-exponential form of the survival amplitude, we find that the instantaneous energy of the considered unstable state can take large values, much larger than the energy of this state for t from the exponential time region. Taking into account results obtained for a considered model, it is hypothesized that this purely quantum mechanical effect may be responsible for the properties of broad resonances such as σ meson as well as having astrophysical and cosmological consequence
No full textPoznańIn this presentation we intend to focus on the exchange of experience between nonlinear optics (optical pulse and beam propagation in nonlinear media) and atom optics (dynamics of coherent waves generated from Bose-Einstein condensates). A common ground here is the nonlinear Schrödinger equation, which with the proper substitution of variables describes both types of phenomena. In nonlinear optics it is a light propagation equation that relates the signal at the end of the nonlinear crystal to the signal at the input face of the medium. In Bose-Einstein condensate dynamics it is the called the Gross-Pitaevskii equation. We will discuss various types of phenomena which have realisations both in the nonlinear optics and atom optics. We will concentrate our consideration on soliton formation, which is a challenge to fundamental and applied research in these two domains of physics
No full textPoznańWe present an exploratory study of a group of patients (150) who have undergone precutaneous transluminal coronary angioplasty with the use of drug eluting stents. We concentrate on the most often studied rare adverse event, i.e. death, as well as the still unexplored cancer variable. The aim of the study is to identify possible statistical hypotheses for a subsequent, large sample study. The results of this study may lead to a change in the therapy administered after precutaneous coronary interventions which will reduce the mortality rate. To achieve this, we use clustering techniques such as hierarchical cluster analysis, principal components methods and interactive brushing. We show that death cases cluster in the space defined by the available variables, while the cancer cases do not seem to cluster
No full textPoznańThe aim of this paper is to give a general setting, based on quantum deformations, for the explicit construction of certain classes of integrable Hamiltonian systems
No full textPoznańA combination of networks, computational, storage infrastructure and the scientific instrumentation (equipped with sensor networks) composes a new kind of e-Infrastructure. The integration of scientific instruments into e-Infrastructure empowers possibilities in conducting experiments. The development of technologies that allow remote and shared access to laboratory instruments opens up new opportunities for researchers. This paper presents an approach to integrate the laboratory instruments with e-Infrastructure, focusing on the results of the EU FP7 DORII project
No full textPoznańWe present a study of the parallel tempering (replica exchange) Monte Carlo method, with special focus on the feedback-optimized parallel tempering algorithm, used for generating an optimal set of simulation temperatures. This method is applied to a lattice simulation of a homopolymer chain undergoing a coil-to-globule transition upon cooling. We select the optimal number of replicas for different chain lengths, N = 25, 50 and 75, using replica's round-trip time in temperature space, in order to determine energy, specific heat, and squared end-to-end distance of the homopolymer chain for the selected temperatures. We also evaluate relative merits of this optimization method
No full textPoznańThe random laser differs from other types of laser in that its cavity is formed not by mirrors but by multiple scattering in a disordered gain medium. Over the course of ten years, random lasers have been attentive by many researchers in the world because their characteristics can lead to unique applications. This report presents the mechanism of random laser operation, classification, characteristics and prediction of different applications. Some research results of authors about random laser have also been noted in report
No full textPoznańThis paper presents recent work that has been performed in the context of high performance computing and hybrid architectures at Poznan Supercomputing and Networking Center. Three algorithms: JPEG2000 – compression/decompression, computational fluid mechanics and motion tracking have been parallelized on various architectures and compared to reference sequential applications. The performance results, implementation issues and best practices are discussed as well
