The Evolution of the Baryon Distribution in the Universe from Cosmological Simulations

The evolution of the baryon distribution in different phases, derived from cosmological simulations, are here reported. These computations indicate that presently most of baryons are in a warm-hot intergalactic (WHIM) medium (about 43%) while at z = 2.5 most of baryons constitute the diffuse medium (about 74%). Stars and the cold gas in galaxies represent only 14% of the baryons at z = 0. For z < 4 about a half of the metals are locked into stars while the fraction present in the WHIM and in the diffuse medium increases with a decreasing redshift. In the redshift range 0 < z < 2.5, the amount of metals in the WHIM increases from 4% to 22% while in the diffuse medium it increases from 0.6% to 4%. This enrichment process is due essentially to a turbulent diffusion mechanism associated to mass motions driven by supernova explosions. At z = 0, simulated blue (late type) galaxies show a correlation of the oxygen abundance present in the cold gas with the luminosity of the considered galaxy that agrees quite well with data derived from HII regions.Comment: 12 pages, 6 figures, to be published in IJMP

Evolution of the Phase-Space Density of Dark Matter Halos and Mixing Effects in Merger Events

Cosmological N-body simulations were performed to study the evolution of the phase-space density Q = rho/sigma^3 of dark matter halos. No significant differences in the scale relations Q ~ sigma^(-2.1) or Q ~ M^(-0.82) are seen for "cold" or "warm" dark matter models. The follow up of individual halos from z = 10 up to the present time indicate the existence of two main evolutionary phases: an early and fast one (10 > z > 6.5), in which Q decreases on the average by a factor of 40 as a consequence of the randomization of bulk motions and a late and long one (6.5 > z > 0), in which Q decreases by a factor of 20 because of mixing induced by merger events. The study of these halos has also evidenced that rapid and positive variations of the velocity dispersion, induced by merger episods, are related to a fast decrease of the phase density Q.Comment: 6 pages, accepted by MNRA

The elastoplastic analysis of planar frames for large displacements by mathematical programming

Imperial Users onl

Cost accounting vs. throughput accounting: answer to the lean production's demands

A produção enxuta tem provocado mudanças significativas nas empresas, mudanças estas que não vêm sendo acompanhadas pelos sistemas de gestão econômica, desenvolvidos sobre pressupostos equivocados da produção em massa que defendem que as otimizações locais isoladas resultam na otimização global da empresa. Deste modo, pode-se afirmar que a contabilidade de custos não é capaz de prover as informações necessárias à correta tomada de decisão nas empresas enxutas. Por outro lado, constata-se uma coerência entre os princípios da produção enxuta e os pressupostos que sustentam a contabilidade de ganhos da Teoria das Restrições. Sendo assim, o objetivo deste artigo é apresentar argumentos que respaldem estas afirmações, bem como justifiquem a necessidade da utilização da contabilidade de ganhos como base teórica para a proposta de um método de gestão econômica para a produção enxuta.Lean production has provoked significant changes in companies. These changes have not being followed by the economic management systems, which are developed based on mistaken assumptions made by mass production which argues that isolated local optimizations can lead to the global optimization of the company. In this way, it can be affirmed that cost accounting cannot provide the necessary information for decision making in lean companies. On the other hand, consistency is evidenced between the principles of the lean production and the assumptions that support the throughput accounting of the Theory of Constraints. Therefore, the objective of this article is to present arguments that corroborate these assertions and justify the necessity for the use of the throughput accounting as a theoretical basis for the proposal of an economic management method for lean production.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

On the cosmological effects of the Weyssenhoff spinning fluid in the Einstein-Cartan framework

The effects of non-Riemannian structures in Cosmology have been studied long ago and are still a relevant subject of investigation. In the seventies, it was discovered that singularity avoidance and early accelerated expansion can be induced by torsion in the Einstein-Cartan theory. In this framework, torsion is not dynamical and is completely expressed by means of the spin sources. Thus, in order to study the effects of torsion in the Einstein-Cartan theory, one has to introduce matter with spin. In principle, this can be done in several ways. In this work we consider the cosmological evolution of the universe in the presence of a constant isotropic and homogeneous axial current and the Weyssenhoff spinning fluid. We analyse possible solutions of this model, with and without the spinning fluid.Comment: Work presented at the 7th Alexander Friedmann International Seminar on Gravitation and Cosmology, Joao Pessoa, Brazil, 29 Jun - 5 Jul 2008. No figures, 5 pages. New version with dynamical equation corrected, new reference and a brief comparison with its experimental bound

First record of the Bicoloured-spined Porcupine Coendou bicolor (Tschudi, 1844) for Brazil

While travelling as part of the protected area management activities undertaken by the Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio) in the state of Acre, four records of porcupines (Coendou spp.) were gathered: two for Coendou bicolor and two for Coendou prehensilis. The records for Coendou bicolor are the first for Brazil while the records for Coendou prehensilis present the state of Acre as a potential region of sympatry between C. bicolor and C. prehensilis

THE ROLE OF NRF2 SIGNALLING IN CELL PROLIFERATION AND TUMORIGENESIS OF CHROMIUM TRANSFORMED HUMAN BRONCHIAL EPITHELIAL CELLS

Hexavalent Chromium (Cr(VI) induces malignant cell transformation in normal bronchial epithelial (BEAS-2B) cells. Cr(VI)-transformed cells exhibit increased level of antioxidants, are resistant to apoptosis, and are tumorigenic. RNAseq analysis in Cr(VI)-transformed cells showed that expression of transcripts associated with mitochondrial oxidative phosphorylation is reduced, and the expression of transcripts associated with pentose phosphate pathway, glycolysis, and glutaminolysis are increased. Sirtuin-3 (SIRT3) regulates mitochondrial adaptive response to stress, such as metabolic reprogramming and antioxidant defense mechanisms. SIRT3 was upregulated and it positively regulated mitochondrial oxidative phosphorylation in Cr(VI)-transformed cells. Our results suggests that SIRT3 plays an important role in mitophagy deficiency of Cr(VI)-transformed cells. Furthermore, SIRT3 knockdown suppressed cell proliferation and tumorigenesis of Cr(VI)-transformed cells. Nrf2 is a transcription factor that regulates oxidative stress response. This study investigated the role of Nrf2 in regulating metabolic reprogramming in Cr(VI)-transformed cells. We observed that in Cr(VI)-transformed cells p-AMPKthr172 was increased, when compared to normal BEAS-2B cells. Additionally, Nrf2 knockdown reduced p-AMPKthr172. Our results suggest that Nrf2 regulated glycolytic shift via AMPK regulation of PFK1/PFK2 pathway. Furthermore, our results showed that Nrf2 constitutive activation in Cr(VI-transformed cells increased cell proliferation and tumorigenesis. Overall this dissertation demonstrated that Cr(VI)-transformed cells undergo metabolic reprogramming. We demonstrated that Nrf2 constitutive activation plays decisive role on metabolic reprogramming induction, and SIRT3 activation contributing to increased cancer cell proliferation and tumorigenesis