Possible black universes in a brane world

A black universe is a nonsingular black hole where, beyond the horizon, there is an expanding, asymptotically isotropic universe. Such spherically symmetric configurations have been recently found as solutions to the Einstein equations with phantom scalar fields (with negative kinetic energy) as sources of gravity. They have a Schwarzschild-like causal structure but a de Sitter infinity instead of a singularity. It is attempted to obtain similar configurations without phantoms, in the framework of an RS2 type brane world scenario, considering the modified Einstein equations that describe gravity on the brane. By building an explicit example, it is shown that black-universe solutions can be obtained there in the presence of a scalar field with positive kinetic energy and a nonzero potential.Comment: 8 pages, 5 figures, gc styl

Wave interaction with defects in pressurised composite structures

There exists a great variety of structural failure modes which must be frequently inspected to ensure continuous structural integrity of composite structures. This work presents a Finite Element (FE) based method for calculating wave interaction with damage within structures of arbitrary layering and geometric complexity. The principal novelty is the investigation of pre-stress effect on wave propagation and scattering in layered structures. A Wave Finite Element (WFE) method, which combines FE analysis with periodic structure theory (PST), is used to predict the wave propagation properties along periodic waveguides of the structural system. This is then coupled to the full FE model of a coupling joint within which structural damage is modelled, in order to quantify wave interaction coeffcients through the joint. Pre-stress impact is quantified by comparison of results under pressurised and non-pressurised scenarios. The results show that including these pressurisation effects in calculations is essential. This is of specific relevance to aircraft structures being intensely pressurised while on air. Numerical case studies are exhibited for different forms of damage type. The exhibited results are validated against available analytical and experimental results

Mathematical modelling and optimization of biomass-plastic fixed-bed downdraft co-gasification process

Co-gasification of woody biomass and polyethylene is studied using mathematical modeling. The gasification process is downdraft fixed-bed. Comparison of modeling results with some experimental data is made. Influence of biomass/plastic ratio and air equivalence ratio on gasification efficiency is investigated

The impact of negative selection on thymocyte migration in the medulla

Developing thymocytes are screened for self-reactivity before they exit the thymus, but how thymocytes scan the medulla for self antigens is unclear. Using two-photon microscopy, we observed that medullary thymocytes migrated rapidly and made frequent, transient contacts with dendritic cells. In the presence of a negative selecting ligand, thymocytes slowed, became confined to areas of approximately 30 mum in diameter and had increased contact with dendritic cells surrounding confinement zones. One third of polyclonal medullary thymocytes also showed confined, slower migration and may correspond to autoreactive thymocytes. Our data suggest that many autoreactive thymocytes do not undergo immediate arrest and death after encountering a negative selecting ligand but instead adopt an altered migration program while remaining in the medullary microenvironment

Nivolumab-containing therapy in patients with newly diagnosed classical Hodgkin lymphoma: own clinical observations and literature review

Classical Hodgkin’s lymphoma (cHL) is a lymphoproliferative disease characterized by the presence of Hodgkin anderezovsky–Reed–Sternberg cells and a tumor microenvironment. Currently, much attention is paid to the microenvironment in cLH. A detailed understanding of the interaction between the tumor and its microenvironment opens up prospects for the cHL diagnosis and treatment. Innovative immunotherapeutic agents such as nivolumab make it possible to control and activate the immune response. Despite the high efficiency of standard protocols in young patients, therapy intensification is associated with organ toxicity and the development of secondary malignant neoplasms. At the same time, in elderly patients, the results of generally accepted antitumor treatment protocols should be considered suboptimal. In the last decade, the treatment of refractory cHL has improved significantly due to the use of immune checkpoint inhibitors.Taking into account the above, the priority issue in modern clinical hematology is to improve cHL treatment strategies not only in elderly but also in young patients by maintaining a balance between high efficacy and low toxicity. Moreover, the inclusion of nivolumab in first-line therapy is not only pathogenetically justified and effective, but also safe. The article presents data from clinical observations of the successful nivolumab use in combination with chemotherapy in patients with newly diagnosed cHL

Evolution of the American Sports Journalism

In this clause evolution of the American sports journalism and its functions in a view of development of the American history and history of the American sports is considered. At different historical stages it is possible to trace evolution both the American mass-media, and genres of journalism. In clause large representatives of the American sports journalism who the materials influenced not only development of journalism, but also the American literature are resulted