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Search Results: 1 - 10 of 1628 matches for " Maciej Maliborski "
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Instability of Flat Space Enclosed in a Cavity
Maciej Maliborski
Physics , 2012, DOI: 10.1103/PhysRevLett.109.221101
Abstract: We consider a spherically symmetric self-gravitating massless scalar field enclosed inside a timelike worldtube $R\times S^3$ with a perfectly reflecting wall. Numerical evidence is given that arbitrarily small generic initial data evolve into a black hole.
A comment on "Boson stars in AdS"
Maciej Maliborski,Andrzej Rostworowski
Physics , 2013,
Abstract: We comment on asymptotically AdS "large-$\sigma$" initial data, studied in Phys. Rev. D87, 123006 (2013) [arXiv:1304.4166], that are immune to turbulent instability.
Lecture Notes on Turbulent Instability of Anti-de Sitter Spacetime
Maciej Maliborski,Andrzej Rostworowski
Physics , 2013, DOI: 10.1142/S0217751X13400204
Abstract: In these lecture notes we discuss recently conjectured instability of anti-de Sitter space, resulting in gravitational collapse of a large class of arbitrarily small initial perturbations. We uncover the technical details used in the numerical study of spherically symmetric Einstein-massless scalar field system with negative cosmological constant that led to the conjectured instability.
Time-periodic solutions in Einstein AdS - massless scalar field system
Maciej Maliborski,Andrzej Rostworowski
Mathematics , 2013, DOI: 10.1103/PhysRevLett.111.051102
Abstract: We construct time-periodic solutions for a system of self-gravitating massless scalar field, with negative cosmological constant, in d+1 spacetime dimensions at spherical symmetry, both perturbatively and numerically. We estimate the convergence radius of the formally obtained perturbative series and argue that it is greater then zero. Moreover, this estimate coincides with the boundary of the convergence domain of our numerical method and the threshold for the black-hole formation. Then we confirm our results with a direct numerical evolution. This also gives strong evidence for nonlinear stability of the constructed time-periodic solutions.
Equivariant wave maps exterior to a ball
Piotr Bizoń,Tadeusz Chmaj,Maciej Maliborski
Mathematics , 2011, DOI: 10.1088/0951-7715/25/5/1299
Abstract: We consider the exterior Cauchy-Dirichlet problem for equivariant wave maps from 3+1 dimensional Minkowski spacetime into the three-sphere. Using mixed analytical and numerical methods we show that, for a given topological degree of the map, all solutions starting from smooth finite energy initial data converge to the unique static solution (harmonic map). The asymptotics of this relaxation process is described in detail. We hope that our model will provide an attractive mathematical setting for gaining insight into dissipation-by-dispersion phenomena, in particular the soliton resolution conjecture.
Resonant dynamics and the instability of anti-de Sitter spacetime
Piotr Bizoń,Maciej Maliborski,Andrzej Rostworowski
Mathematics , 2015, DOI: 10.1103/PhysRevLett.115.081103
Abstract: We consider spherically symmetric Einstein-massless-scalar field equations with negative cosmological constant in five dimensions and analyze evolution of small perturbations of anti-de Sitter spacetime using the recently proposed resonant approximation. We show that for typical initial data the solution of the resonant system develops an oscillatory singularity in finite time. This result hints at a possible route to establishing instability of AdS under arbitrarily small perturbations.
Capability of the Free-Ion Eigenstates for Crystal-Field Splitting  [PDF]
Jacek Mulak, Maciej Mulak
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.211170
Abstract: Any electronic eigenstate of the paramagnetic ion open-shell is characterized by the three independent multipole asphericities for and 6 related to the second moments of the relevant crystal-field splittings by , where . The Ak as the reduced matrix elements can serve as a reliable measure of the state capability for the splitting produced by the k-rank component of the crystal-field Hamiltonian. These multipolar characteristics allow one to verify any fitted crystal-field parameter set by comparing the calculated second moments and the experimental ones of the relevant crystal-field splittings. We present the multipole characteristics Ak for the extensive set of eigenstates from the lower parts of energy spectra of the tripositive 4 f N ions applying in the calculations the improved eigenfunctions of the free lanthanide ions obtained based on the M. Reid f-shell programs. Such amended asphericities are compared with those achieved for the simplified Russell-Saunders states. Next, they are classified with respect to the absolute or relative weight of Ak in the multipole structure of the considered states. For the majority of the analyzed states (about 80%) the Ak variation is of order of only a few percent. Some essential changes are found primarily for several states of Tm3+, Er3+, Nd3+, and Pr3+ ions. The detailed mechanisms of such Ak changes are unveiled. Particularly, certain noteworthy cancelations as well as enhancements of their magnitudes are explained.
Soy Consumption and Obesity  [PDF]
Dante Roccisano, Maciej Henneberg
Food and Nutrition Sciences (FNS) , 2012, DOI: 10.4236/fns.2012.32038
Abstract: Obesity is now present worldwide, including China, India and developing countries. It now seems no longer acceptable to argue that obesity can simply be explained in terms of caloric consumption only using simple concept of energy in and energy out. There may be specific causes of altered metabolism that produce nutritional imbalances. Individual variation in response to food intake may also be considered. Specific substances in the food chain can influence meta-bolism towards an increase in fat deposits. Xenoestrogens have been suggested to have such an influence. Soy contains phytoestrogens plus phytates, protease inhibitors and other anti-nutrients which block or compromise the body’s uptake of essential vitamins and minerals. This may contribute to nutritional anomalies. We analyzed data from WHO and FAO for 167 countries. These contained percentage of obese individuals (BMI > 30 kg/m2), GDP, caloric consump-tion per capita, and sugar and soy consumption per capita. Regressions and partial correlations were used. Soy con-sumption correlates significantly with levels of obesity, irrespective of GDP and caloric intake. For instance, poor Latin America with soy consumption of 28.9 kg/person/year has more obesity (18.4%) than better off European Union (14.1%) consuming 16.1 kg/person/year of soy. Soy consumption seems to contribute approximately 10% - 21% to the worldwide variation in obesity, depending on the method of statistical analysis. The ubiquitous presence of unfermented soy products in mass produced foods seems to be an important contributor to the obesity epidemic.
Nanoparticle Technology as a Double-Edged Sword: Cytotoxic, Genotoxic and Epigenetic Effects on Living Cells  [PDF]
Mytych Jennifer, Wnuk Maciej
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2013, DOI: 10.4236/jbnb.2013.41008
Abstract: Nanoparticles are considered as powerful tools in nanotechnological applications. Due to their unique physicochemical properties, their interactions with different biological systems have been shown. Nanomaterials have been successfully used as coating materials or treatment and diagnosis tools. Nevertheless, toxic effects of nanoparticles in vitro and in vivo have also been reported. Here, we summarize the current state of knowledge on exposure routes, cellular uptake and toxicological activities of the commonly used nanoparticles. In this context, we discuss the mechanisms of toxicity of nanoparticles involving perturbation of redox milieu homeostasis and cellular signaling pathways.
De Sitter Space as a Computational Tool for Surfaces and Foliations  [PDF]
Maciej Czarnecki, Szymon Walczak
American Journal of Computational Mathematics (AJCM) , 2013, DOI: 10.4236/ajcm.2013.31A001

The set of all spheres and hyperplanes in the Euclidean space Rn+1 could be identified with the Sitter space Λn+1. All the conformal properties are invariant by the Lorentz form which is natural pseudo-Riemannian metric on Λn+1. We shall study behaviour of some surfaces and foliations as their families using computation in the de Sitter space.

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