The cosmological model with running dark energy is considered. We assume that the vacuum of the Universe is in a meta-stable state and decays into a true (bare) vacuum state with increasing time. We ...use quantum theory of decay processes to find energy of the system in the unstable state and apply obtained results to a description of the running dark energy identified with vacuum energy. We also estimate model parameters using astronomical data. From the astronomical point of view our model is in good agreement with data. Moreover, the framework of this model one can explain naturally, smallness of the cosmological constant parameter Λbare.
Within the quantum mechanical treatment of the decay problem one finds that at late times tthe survival probability of an unstable state cannot have the form of an exponentially decreasing function ...of time t but it has an inverse power-like form. This is a general property of unstable states following from basic principles of quantum theory. The consequence of this property is that in the case of false vacuum states the cosmological constant becomes dependent on time: Λ - Λbare ≡ Λ(t) - Λbare ∼ 1 t2. We construct the cosmological model with decaying vacuum energy density and matter for solving the cosmological constant problem and the coincidence problem. We show the equivalence of the proposed decaying false vacuum cosmology with the Λ(t) cosmologies (the Λ(t)CDM models). The cosmological implications of the model of decaying vacuum energy (dark energy) are discussed. We constrain the parameters of the model with decaying vacuum using astronomical data. For this aim we use the observation of distant supernovae of type Ia, measurements of H(z), BAO, CMB and others. The model analyzed is in good agreement with observation data and explain a small value of the cosmological constant today.
Rapid development of urban areas always comes with great side effects. One of them is the occurrence of urban floods. Growth of impervious surfaces in cities leads to increasing run-off values. This ...together with difficulties connected with sewage modernization in cities marks urban inundations as being one of the most important issues concerning urban water. Accurate prediction of a phenomenon is difficult as it is highly dependent on local conditions and the quality of available data about them. A most recent approach to modelling urban flooding involves a detailed description of the interaction between storm water sewage flow modelling and surface flow modelling. In this paper we will describe a numerical model of urban inundation that is being used to analyse the phenomenon, which consists of 1D storm water flow model (explicit McCormack scheme) and 1D surface flow model (diffusive wave). But before that laboratory tests describing the interaction between used models will be introduced. We will try to evaluate how different surface flow conditions affect interaction and find out if there is an easy way to implement it in coupled numerical modelling of large-scale urban areas inundations. Because tests are still being conducted and further investigation of phenomenon is being done, the conclusions are only preliminary and should be treated as a guideline for future work.
We study the dynamics of a non‐minimally coupled scalar field cosmology with a potential function. We use the framework of dynamical systems theory to investigate all evolutional paths admissible for ...all initial conditions. Additionally, we assume the presence of barotropic matter and show that the dynamics can be formulated in terms of an autonomous dynamical system. We have found fixed points corresponding to three main stages of the evolution of the universe, namely, radiation, matter and quintessence domination epochs. Using the linearization of the dynamical systems in the vicinity of the critical points we explicitly obtain formulas determining the effective equation of state parameter for the universe at different epochs. In our approach the form of w(z) parametrisation is derived directly from the dynamical equations rather than postulated a priori.
Post-transplant diabetes mellitus (PTDM) is a metabolic disorder occurring after solid organ transplantation during the therapy with calcineurin inhibitors. ATP-sensitive potassium channels KCNJ11 ...and KCNQ1 play an important role in the regulation of insulin secretion by β cells and development of diabetes mellitus. Numerous studies have confirmed the association between KCNJ11 and KCNQ1 gene polymorphisms and type 2 diabetes. The aim of this study was to examine the association between KCNJ11 and KCNQ1 gene polymorphisms and posttransplant diabetes mellitus in kidney allograft recipients treated with tacrolimus. The study included 201 patients who received kidney transplants. The patients were subdivided into two subgroups: patients with PTDM (N = 35) and patients without PTDM (N = 166). The association between KCNJ11 and KCNQ1 gene polymorphisms and post-transplant diabetes was studied in three models of univariate Cox regression analysis, i.e., additive, dominant and recessive. In these three models there were no statistically significant associations between KCNJ11 and KCNQ1 gene polymorphisms and PTDM. The results of this study suggest lack of association between KCNJ11 and KCNQ1 gene polymorphisms and post-transplant diabetes mellitus in kidney allograft recipients treated with tacrolimus in the Polish population.
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