345 research outputs found

    Microscopic/stochastic timesteppers and coarse control: a kinetic Monte Carlo example

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    Coarse timesteppers provide a bridge between microscopic / stochastic system descriptions and macroscopic tasks such as coarse stability/bifurcation computations. Exploiting this computational enabling technology, we present a framework for designing observers and controllers based on microscopic simulations, that can be used for their coarse control. The proposed methodology provides a bridge between traditional numerical analysis and control theory on the one hand and microscopic simulation on the other

    Knaster's problem for (Z2)k(Z_2)^k-symmetric subsets of the sphere S2k1S^{2^k-1}

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    We prove a Knaster-type result for orbits of the group (Z2)k(Z_2)^k in S2k1S^{2^k-1}, calculating the Euler class obstruction. Among the consequences are: a result about inscribing skew crosspolytopes in hypersurfaces in R2k\mathbb R^{2^k}, and a result about equipartition of a measures in R2k\mathbb R^{2^k} by (Z2)k+1(Z_2)^{k+1}-symmetric convex fans

    The complete genome sequence of Pantoea ananatis AJ13355, an organism with great biotechnological potential

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    Pantoea ananatis AJ13355 is a newly identified member of the Enterobacteriaceae family with promising biotechnological applications. This bacterium is able to grow at an acidic pH and is resistant to saturating concentrations of L-glutamic acid, making this organism a suitable host for the production of L-glutamate. In the current study, the complete genomic sequence of P. ananatis AJ13355 was determined. The genome was found to consist of a single circular chromosome consisting of 4,555,536 bp [DDBJ: AP012032] and a circular plasmid, pEA320, of 321,744 bp [DDBJ: AP012033]. After automated annotation, 4,071 protein-coding sequences were identified in the P. ananatis AJ13355 genome. For 4,025 of these genes, functions were assigned based on homologies to known proteins. A high level of nucleotide sequence identity (99%) was revealed between the genome of P. ananatis AJ13355 and the previously published genome of P. ananatis LMG 20103. Short colinear regions, which are identical to DNA sequences in the Escherichia coli MG1655 chromosome, were found to be widely dispersed along the P. ananatis AJ13355 genome. Conjugal gene transfer from E. coli to P. ananatis, mediated by homologous recombination between short identical sequences, was also experimentally demonstrated. The determination of the genome sequence has paved the way for the directed metabolic engineering of P. ananatis to produce biotechnologically relevant compounds

    Lonsdaleite polygenesis and typomorphism

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    The effect of vaccination on the severity of Covid-19 transmission in the working population

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    The aim of the study – to find out the effectiveness of vaccination during the fight against Covid – 19. To analyze statistical data on the number of cases and the severity of the course of the disease, to draw conclusions based on the analysis.Цель исследования – выяснить эффективность вакцинации во время борьбы с Covid– 19. Проанализировать статистические данные по количеству заболевших и тяжести течения заболевания, сделать на основе анализа выводы

    Evolution of the nuclear modification factors with rapidity and centrality in d+Au collisions at $\sqrt{s_{NN}} = 200 GeV

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    We report on a study of the transverse momentum dependence of nuclear modification factors RdAuR_{dAu} for charged hadrons produced in deuteron + gold collisions at sNN=200\sqrt{s_{NN}}= 200GeV, as a function of collision centrality and of the pseudorapidity (η=0,1,2.2,3.2\eta = 0,1,2.2,3.2) of the produced hadrons. We find significant and systematic decrease of RdAuR_{dAu} with increasing rapidity. The midrapidity enhancement and the forward rapidity suppression are more pronounced in central collisions relative to peripheral collisions. These results are relevant to the study of the possible onset of gluon saturation at RHIC energies.Comment: Four pages, four figures. Published in PRL. Figures 1 and 2 have been updated, and several changes made to the tex

    Impact of toxicity effects of zinc oxide nanoparticles in rats within acute and subacute experiments

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    Introduction. Occupational air is contaminated with zinc oxide nanoparticles in the copper smelting industry, especially in the smelting of brass and copper. A wide range of toxic effects with varied clinical symptomatology is observed in zinc and its compounds. Competitive relations with many other metals, including calcium, copper, and iron, are the foundation of most cases of zinc intoxication. Long-term administration of zinc or its compounds to laboratory rodents affects enzymes, carbohydrates and mineral metabolism. Materials and methods. Subchronic intoxication with repeated intraperitoneal injections and acute low respiratory tract reaction to a single intratracheal injection of zinc nanoparticles were simulated in outbred white rats. Water suspensions of zinc oxide nanoparticles with a 30-80 nm diameter were applied in both experimental models. Upon completion of the exposure, the condition of the rats in all groups was evaluated in many generally accepted criteria for toxicity. The student’s t-test was applied for statistical analysis of the obtained data. Results. Moderate intoxication development in a subchronic experiment is demonstrated. Homogeneous ultrastructural changes in the spleen tissue were revealed. Mitochondrial damage with partial or complete loss of crista is the most common. The fragmentation ratio of DNA was found by a statistically significant increase. A single intratracheal injection of zinc oxide nanoparticles revealed the increase in the attraction of cells capable of their phagocytosis (mainly neutrophils) into the low respiratory tract. This shows their cytotoxicity. Conclusion. Moderate general toxic and cytotoxic effects of zinc oxide nanoparticles on the rat body were identified. © 2021 Izdatel'stvo Meditsina. All rights reserved

    Recent Results from the BRAHMS Experiment

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    We present recent results obtained by the BRAHMS experiment at the Relativistic Heavy Ion Collider (RHIC) for the systems of Au + Au and Cu + Cu at \rootsnn{200} and at 62.4 GeV, and p + p at \rootsnn{200}. Nuclear modification factors for Au + Au and Cu + Cu collisions are presented. Analysis of anti-particle to particle ratios as a function of rapidity and collision energy reveal that particle populations at the chemical freeze-out stage for heavy-ion reactions at and above SPS energies are controlled by the baryon chemical potential. From the particle spectra we deduce significant radial expansion (β\beta \approx 0.75), as expected for systems created with a large initial energy density. We also measure the elliptic flow parameter v2v_2 versus rapidity and \ptn. We present rapidity dependent p/πp/\pi ratios within 0<y<30 < y < 3 for Au + Au and Cu + Cu at \rootsnn{200}. \Raa is found to increase with decreasing collision energy, decreasing system size, and when going towards more peripheral collisions. However, \Raa shows only a very weak dependence on rapidity (for 0<y<3.20 < y < 3.2), both for pions and protons.Comment: 16 pages and 14 figures, proceedings for plenary talk at Quark Matter 2005, Budapest, Hungar

    Biological Prophylaxis in the System of the Management of Occupational Risk Due to Exposure of Metal-Containing Nanoparticles

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    With taking into account the biological toxicity of metallic and metal oxide nanoparticles to be a well-established fact, the widespread use of nanotechnologies and the significant proportion of nanoscale particles in industrial aerosols released during many pyrometallurgical and electric welding processes determine the importance of searching for approaches to increase the organism's resistance to them. Results of a number of experiments show the application of combinations of some bioactive agents composed in accordance with sound theoretical premises and used in innocuous doses to be potent of the significant attenuation of the integral and specific toxicity of metallic nanoparticles and even their genotoxicity. Further research followed by practical application of the results is a promising trend in the occupational risk management strategy. © СOLLECTIVE OF AUTHORS, 2017

    Nuclear Stopping in Au+Au Collisions at sqrt(sNN) = 200 GeV

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    Transverse momentum spectra and rapidity densities, dN/dy, of protons, anti-protons, and net--protons (p-pbar) from central (0-5%) Au+Au collisions at sqrt(sNN) = 200 GeV were measured with the BRAHMS experiment within the rapidity range 0 < y < 3. The proton and anti-proton dN/dy decrease from mid-rapidity to y=3. The net-proton yield is roughly constant for y<1 at dN/dy~7, and increases to dN/dy~12 at y~3. The data show that collisions at this energy exhibit a high degree of transparency and that the linear scaling of rapidity loss with rapidity observed at lower energies is broken. The energy loss per participant nucleon is estimated to be 73 +- 6 GeV.Comment: 5 pages, 4 figure
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