303 research outputs found

    Development of the Biosphere in the Context of Some Fundamental Inventions of Biological Evolution

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    Traditionally, the evolution of flora and fauna on the Earth as well as the evolution of their physical and chemical environment are considered separately. At the same time, when considering the global evolutionary changes, it becomes clear that the evolution of all these components occurs in close relationship and that they together constitute a unified evolutionary process. Thus, we should talk about their co-evolution and that the whole biosphere is a united functional system. In this chapter, we briefly discuss some of the major “inventions” of ancient life that are responsible for global biosphere transformations and which “worked” in the biosphere until now (photosynthesis, eukaryotic cell, multicellular organism, and the other findings). The evolution of the Precambrian life as well as the Phanerozoic stage of the biosphere evolution are considered in this context

    Dynamics of Dirac solitons in networks

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    We study dynamics of Dirac solitons in prototypical networks modeling them by the nonlinear Dirac equation on metric graphs. Stationary soliton solutions of the nonlinear Dirac equation on simple metric graphs are obtained. It is shown that these solutions provide reflectionless vertex transmission of the Dirac solitons under suitable conditions. The constraints for bond nonlinearity coefficients, conjectured to represent necessary conditions for allowing reflectionless transmission over a Y-junction are derived. The Y-junction considerations are also generalized to a tree and triangle network. The analytical results are confirmed by direct numerical simulations. Keywords: nonlinear Dirac equation, metric graphs, Lorentz transformation, Gross–Neveu model, Dirac solitons, reflectionless transpor

    Nanostructural Engineering of Steel

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    The concept of microstructural engineering of steels is well established and is the basis for a wide range of processes and products. Recently, though, there has been increasing emphasis in developing microstructures that have submicron length scales and also in understanding in far greater detail the structures and solute effects that are occurring at the nanoscale. In this review it is proposed that we are heading towards the situation where we are applying nanostructural engineering concepts in the development of new steels. A range of examples are given as well as a discussion of the potential impact of new processing routes. Clearly the future advances will be driven through improved characterization methods, such as atom probe tomography, in combination with advanced modeling

    Measurement of air and nitrogen fluorescence light yields induced by electron beam for UHECR experiments

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    Most of the Ultra High Energy Cosmic Ray (UHECR) experiments and projects (HiRes, AUGER, TA, EUSO, TUS,...) use air fluorescence to detect and measure extensive air showers (EAS). The precise knowledge of the Fluorescence Light Yield (FLY) is of paramount importance for the reconstruction of UHECR. The MACFLY - Measurement of Air Cherenkov and Fluorescence Light Yield - experiment has been designed to perform such FLY measurements. In this paper we will present the results of FLY in the 290-440 nm wavelength range for dry air and pure nitrogen, both excited by electrons with energy of 1.5 MeV, 20 GeV and 50 GeV. The experiment uses a 90Sr radioactive source for low energy measurement and a CERN SPS electron beam for high energy. We find that the FLY is proportional to the deposited energy (E_d) in the gas and we show that the air fluorescence properties remain constant independently of the electron energy. At the reference point: atmospheric dry air at 1013 hPa and 23C, the ratio FLY/E_d=17.6 photon/MeV with a systematic error of 13.2%.Comment: 19 pages, 8 figures. Accepted for publication in Astroparticle Physic

    Measurement of air fluorescence light yield induced by an electromagnetic shower

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    For most of the Ultra High Energy Cosmic Ray (UHECR) experiments and projects (HiRes, AUGER, TA, JEM-EUSO, TUS,...), the detection technique of Extensive Air Showers (EAS) is based, at least, on the measurement of the air fluorescence induced signal. The knowledge of the Fluorescence Light Yield (FLY) is of paramount importance for the UHECR energy reconstruction. The MACFLY experiment was designed to perform such FLY measurements. In this paper we will present the results of dry air FLY induced by 50 GeV electromagnetic showers as a function of shower age and as a function of the pressure. The experiment was performed at CERN using an SPS electron test beam line. It is shown that the FLY is proportional to deposited energy in air (E_d) and that the ratio FLY/E_d and its pressure dependence remain constant independently of shower age and more generally independently of the excitation source used (single electron track or air shower).For most of the Ultra High Energy Cosmic Ray (UHECR) experiments and projects (HiRes, AUGER, TA, JEM-EUSO, TUS,...), the detection technique of Extensive Air Showers (EAS) is based, at least, on the measurement of the air fluorescence induced signal. The knowledge of the Fluorescence Light Yield (FLY) is of paramount importance for the UHECR energy reconstruction. The MACFLY experiment was designed to perform such FLY measurements. In this paper we will present the results of dry air FLY induced by 50 GeV electromagnetic showers as a function of shower age and as a function of the pressure. The experiment was performed at CERN using an SPS electron test beam line. It is shown that the FLY is proportional to deposited energy in air (E_d) and that the ratio FLY/E_d and its pressure dependence remain constant independently of shower age and more generally independently of the excitation source used (single electron track or air shower)

    Predictors of left ventricular hypertrophy development in patients with essential hypertension: role of pro- and anti-inflammatory cytokines

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    Objective: The data on the relationship between the level of TNF-α and interleukin-10 with the presence of left ventricular hypertrophy and myocardial remodeling in patients with essential hypertension is presented. Methods: Overall, 156 patients with essential hypertension aged 40 to 75 years (with mean age 55.8 ± 7.5 years) were examined; of which 57 were women and 99 were men. All patients were divided into two groups. The first group included 73 patients showing the presence of  left ventricular hypertrophy (LVH), established by echocardiography; the second group included 83 patients who showed no signs of LVH on the echocardiogram. Results: According to the study, no relationship was found between the concentration of tumor necrosis factor α (TNF-α) and the development of LVH. It was also shown that only men, but not women with, were associated with the presence of LVH with low levels of interleukin-10 ( IL-10). In addition, a negative correlation was found between the concentration of tumor necrosis factor α (TNF-α) and IL-10 with the thickness of the left ventricular walls at the initial stages of myocardial remodeling on the echocardiography. Conclusion: Thus, our study demonstrates the modulating role of inflammation on the processes of myocardial remodeling in hypertension

    The relationship of cytokine status with left ventricular hypertrophy in patients with arterial hypertension

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    Aim. To study the relationship of tumor necrosis factor α and interleukin-10 levels with the presence of left ventricular hypertrophy and myocardial remodeling in patients with arterial hypertension. Metods. 156 patients with hypertension aged 40 to 75 years (mean age 55.8±7.5 years), including 57 women and 99 men were examined. All patients were divided into two groups. Group 1 included 83 patients without left ventricular hypertrophy (55.5±7.5 years), group 2 included 73 patients with left ventricular hypertrophy (56.2±7.8 years), established by echocardiographic signs. All patients in addition to the general clinical examination and biochemical studies had echocardiography and Doppler echocardiography performed, as well as measurement of the concentration of tumor necrosis factor α and interleukin-10 by solid-phase enzyme immunoassay using specialized «Cytokine-Stimulus-Best» kit (Novosibirsk, Russia). Results. The concentration of tumor necrosis factor α in patients without left ventricular hypertrophy was 8.43±1.36 pg/ml and was comparable with the concentration of this cytokine in patients with left ventricular hypertrophy (8.54±1.58 pg/ml, p >0.05). This pattern was typical for both men and women. The concentration of interleukin-10 in both groups was also comparable (15.4±3.6 pg/ml in group 1 and 14.7±3.4 pg/ml in group 2, p >0.05). However, we identified gender-specific features in the relationship of interleukin-10 with the presence of left ventricular hypertrophy in patients with hypertension. Thus, while in women the concentration of cytokine in groups with/without left ventricular hypertrophy did not differ significantly, in men without hypertrophy the level of interleukin-10 of 15.7±3.6 pg/ml, was significantly higher than the value of the same indicator in the group of men with left ventricular hypertrophy (14.8±2.9 pg/ml, p <0.025). Multivariate regression analysis showed that tumor necrosis factor α and interleukin-10 concentrations correlated to left ventricular wall thickness in patients without left ventricular hypertrophy. No such pattern was revealed for patients with hypertrophy. Conclusion. The results demonstrate the modulating role of tumor necrosis factor α and interleukin-10 in myocardial remodeling processes in arterial hypertension
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