Inflationary cosmology with Chaplygin gas in Palatini formalism

We present a simple generalisation of the $\Lambda$CDM model which on the one hand reaches very good agreement with the present day experimental data and provides an internal inflationary mechanism on the other hand. It is based on Palatini modified gravity with quadratic Starobinsky term and generalized Chaplygin gas as a matter source providing, besides a current accelerated expansion, the epoch of endogenous inflation driven by type III freeze singularity. It follows from our statistical analysis that astronomical data favors negative value of the parameter coupling quadratic term into Einstein-Hilbert Lagrangian and as a consequence the bounce instead of initial Big-Bang singularity is preferred.Comment: 19 pages, 6 figures, typos corrected; version accepted by JCA

Do sewn singularities falsify the Palatini cosmology?

We investigate further (cf. arXiv:1512.01199, JCAP01 (2016) 040) Starobinsky cosmological model $R+\gamma R^2$ in the Palatini formalism with Chaplygin gas and baryonic matter as a source. For this aim we use dynamical system theory. The dynamics is reduced to the 2D sewn dynamical system of a Newtonian type (a piecewise-smooth dynamical system). We classify all evolutional paths in the model as well as trajectories in the phase space. We demonstrate the presence of a degenerate freeze singularity (glued freeze type singularities) for the positive $\gamma$. In this case it is a generic feature of early evolution of the universe. We point out that a degenerate type III of singularity can be considered as an endogenous model of inflation between the matter dominating epoch and the dark energy phase. We also investigate cosmological models with negative $\gamma$. It is demonstrated that $\gamma$ equal zero is a bifurcation parameter and dynamics qualitatively changes in comparison to positive $\gamma$. Instead of the big bang the sudden bounce singularity of a finite scale factor appears and there is a generic class of bouncing solutions sewn along the line $a=a_{\text{sing}}$. And we argue that the presence of sudden singularities in an evolutional scenario of the Universe falsifies the negative $\gamma$ in the Palatini cosmology. Only very small values of $\Omega_{\gamma}$ parameter are admissible if we requires that agreements physics with the $\Lambda$CDM model. From the statistical analysis of astronomical observations, we deduce that the case of negative values of $\Omega_\gamma$ can be rejected even if it may fit better to the data.Comment: 26 pages, 15 figures, v3: change of title, more discussion on singularitie

Reminiscencje z podróży Polaków po Sudetach na podstawie XIX-wiecznych relacji

The article presents the stages of gradual exploration of the Sudetes over the centuries. The main objective was to present descriptions and accounts published by Poles in the 19th century. The first wanderers gave their impressions of the visited region in local newspapers and chronicles, combining various thematic threads such as natural, historical, and socio-economic. These observations were taken into account based on the visits of Poles in the mountains, spas and anthropogenic facilities

Description of invariant NKT cells.

Recently discovered subpopulations belonging to cell groups called “invariant” NKT, also referred to as type I NKT or classical NKT cells, appear to have a unique impact on the tumor microenvironment. Considering the characteristics of secreted cytokines, production of chemokines and the capability of cell cytotoxic activity, these cells have a significant function in being immune to bacteria, parasites, viruses, autoimmune and tumor diseases. The profile of secreted cytokine is probably decisive in reference to the distinct functions of the subpopulation, some of them exhibit immunosuppressive activity inhibiting an anticancer immune response, and the other stimulate the organisms for eradicating the tumor. Currently, it has been discovered six fundamental, functionally distinct subpopulations of iNKT cells (NKT1, NKT2, NKT10, NKT17, NKTreg, NKTFH).Recently discovered subpopulations belonging to cell groups called “invariant” NKT, also referred to as type I NKT or classical NKT cells, appear to have a unique impact on the tumor microenvironment. Considering the characteristics of secreted cytokines, production of chemokines and the capability of cell cytotoxic activity, these cells have a significant function in being immune to bacteria, parasites, viruses, autoimmune and tumor diseases. The profile of secreted cytokine is probably decisive in reference to the distinct functions of the subpopulation, some of them exhibit immunosuppressive activity inhibiting an anticancer immune response, and the other stimulate the organisms for eradicating the tumor. Currently, it has been discovered six fundamental, functionally distinct subpopulations of iNKT cells (NKT1, NKT2, NKT10, NKT17, NKTreg, NKTFH)