92 research outputs found

    Productivity of spring barley on soils of different agroecological groups of r. Tatarstan, Nizhnekamsk district

    Get PDF
    In this work, the contribution of the group of main agroecological factors to the final yield of spring barley was assessed using the model of principal component method and multivariate regression. It was found that in the conditions of the forest-steppe zone of Tatarstan the most significant factors are the group of variables that determine the conditions of heat and moisture availability, namely: the amount of precipitation during the growing season, the amount of temperature during the growing season, morphometric parameters of slope steepness and exposure. The method and depth of tillage did not have a significant effect on the final yield, as well as a number of other variables analyzed: forms of fertilizers used, predecessors in crop rotation, etc. Such variable as Exposition was not significantly related to Yield. With Pearson correlation method R=0.30 units, which is not reliable at n=31, but Exposition had a significant effect on Temperatures > 10 and Precipitation (R=0.78 units and -0.77 units), the strongest and most important factors in the formation of Yield. The information obtained will be very valuable in the development of management approaches, rational agro-technologies and adaptive systems

    Изучение видового разнообразия бактерий рода Bifidobacterium кишечной микрофлоры с использованием метода MALDI-TOF масс-спектрометрии

    Get PDF
    Background: The members of genus Bifidobacterium represent a significant part of intestinal microbiota in adults and predominate in infants. Species repertoire of the intestinal bifidobacteria is known to be subjected to major changes with age; however, many details of this process are still to be elucidated.Objective: Our aim was to study the diversity of intestinal bifidobacteria and changes of their qualitative and quantitative composition characteristics during the process of growing up using MALDI-TOF mass-spectrometric analysis of pure bacterial cultures.Methods: A cross-sectional study of bifidobacteria in the intestinal microbiota was performed in 93 healthy people of the ages from 1 month to 57 years. Strains were identified using Microflex LT MALDI-TOF MS, the confirmation was performed by 16S rRNA gene fragment sequencing.Results: 93% of isolated bifidobacterial strains were successfully identified using MALDI-TOF mass-spectrometry. At least two of the strains from each species were additionally identified by 16S rRNA gene fragment sequencing, in all of the cases the results were the same. It was shown that the total concentration of bifidobacteria decreases with age (p 0.001) as well as the frequency of isolation of Bifidobacterium bifidum (p =0.020) and Bifidobacterium breve (p 0.001), and the frequency of isolation of Bifidobacterium adolescentis, increases (p 0.001), representing the continuous process of transformation of microbiota.Conclusion: The method of MALDI-TOF mass spectrometry demonstrated the ability to perform rapid and reliable identification of bifidobacteria that allowed the study of changes in the quantitative and qualitative characteristics of human microbiota in the process of growing up.Представители рода Bifidobacterium представляют значительную часть микрофлоры кишечника взрослых людей и численно доминируют в микрофлоре младенцев. Известно, что видовой состав кишечных бифидобактерий подвергается сильным изменениям с возрастом, однако многие детали этого процесса остаются неясными.Цель исследования: изучить видовое разнообразие бифидобактерий кишечника и изменения их качественного и количественного состава в процессе взросления человека при помощи технологии MALDI-TOF масс-спектрометрического анализа белковых профилей чистых культур.Методы: кросс-секционное исследование разнообразия бифидобактерий в составе нормальной микрофлоры кишечника проведено у 93 человек в возрасте от 1 мес до 57 лет. Осуществляли выделе- ние чистых культур и их идентификацию на приборе Microflex LT MALDI-TOF MS (Bruker Daltonics, Германия), подтверждение реализовывали с использованием секвенирования фрагмента гена 16S рРНК.Результаты: с применением MALDI-TOF масс-спектрометрии было успешно идентифицировано 93% выделенных штаммов бифидобактерий. Минимум по 2 представителя от каждого из видов были дополнительно определены методом секвенирования фрагмента гена 16SрРНК; во всех случаях результаты методов совпали. Показано, что с возрастом происходит снижение общей концентрации бифидобактерий (p 0,001), уменьшается встречаемость видов Bifidobacterium bifidum (p =0,020) и Bifidobacterium breve (p 0,001), а встречаемость вида Bifidobacterium adolescentis увеличивается (p 0,001), отражая постепенные процессы перестройки микрофлоры.Заключение: метод MALDI-TOF масс-спектрометрии показал возможность быстрой и надежной идентификации бифидобактерий, позволившей провести исследование изменений количественных и качественных показателей микрофлоры человека в процессе взрослени

    Modulation control and spectral shaping of optical fiber supercontinuum generation in the picosecond regime

    Full text link
    Numerical simulations are used to study how fiber supercontinuum generation seeded by picosecond pulses can be actively controlled through the use of input pulse modulation. By carrying out multiple simulations in the presence of noise, we show how tailored supercontinuum Spectra with increased bandwidth and improved stability can be generated using an input envelope modulation of appropriate frequency and depth. The results are discussed in terms of the non-linear propagation dynamics and pump depletion.Comment: Aspects of this work were presented in Paper ThJ2 at OECC/ACOFT 2008, Sydney Australia 7-10 July (2008). Journal paper submitted for publication 30 July 200

    The semileptonic decays of the B_c meson

    Get PDF
    We study the semileptonic transitions B_c to \eta_c, J/\psi, D, D^*, B, B^*, B_s, B_s^* in the framework of a relativistic constituent quark model. We use experimental data on leptonic J/\psi decay, lattice and QCD sum rule results on leptonic B_c decay, and on radiative \eta_c transitions to adjust the quark model parameters. We compute all form factors of the above semileptonic B_c-transitions and give predictions for various semileptonic B_c decay modes including their \tau-modes when they are kinematically accessible. The implications of heavy quark symmetry for the semileptonic decays are discussed and are shown to be manifest in our explicit relativistic quark model calculation. A comparison of our results with the results of other calculations is performed.Comment: 31 pages Latex (uses epsf, revtex). Section II expanded, typos corrected. This version will appear in Phys. Rev.

    Crossovers in Unitary Fermi Systems

    Full text link
    Universality and crossover is described for attractive and repulsive interactions where, respectively, the BCS-BEC crossover takes place and a ferromagnetic phase transition is claimed. Crossovers are also described for optical lattices and multicomponent systems. The crossovers, universal parameters and phase transitions are described within the Leggett and NSR models and calculated in detail within the Jastrow-Slater approximation. The physics of ultracold Fermi atoms is applied to neutron, nuclear and quark matter, nuclei and electrons in solids whenever possible. Specifically, the differences between optical lattices and cuprates is discussed w.r.t. antiferromagnetic, d-wave superfluid phases and phase separation.Comment: 50 pages, 15 figures. Contribution to Lecture Notes in Physics "BCS-BEC crossover and the Unitary Fermi Gas" edited by W. Zwerge

    Origins of the Ambient Solar Wind: Implications for Space Weather

    Full text link
    The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

    Single Spin Asymmetry ANA_N in Polarized Proton-Proton Elastic Scattering at s=200\sqrt{s}=200 GeV

    Get PDF
    We report a high precision measurement of the transverse single spin asymmetry ANA_N at the center of mass energy s=200\sqrt{s}=200 GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The ANA_N was measured in the four-momentum transfer squared tt range 0.003t0.0350.003 \leqslant |t| \leqslant 0.035 \GeVcSq, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of ANA_N and its tt-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this s\sqrt{s}, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure

    Effect of event selection on jetlike correlation measurement in d+Au collisions at sNN=200 GeV

    Get PDF
    AbstractDihadron correlations are analyzed in sNN=200 GeV d+Au collisions classified by forward charged particle multiplicity and zero-degree neutral energy in the Au-beam direction. It is found that the jetlike correlated yield increases with the event multiplicity. After taking into account this dependence, the non-jet contribution on the away side is minimal, leaving little room for a back-to-back ridge in these collisions

    Beam-energy Dependence Of Charge Balance Functions From Au + Au Collisions At Energies Available At The Bnl Relativistic Heavy Ion Collider

    Get PDF
    Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Balance functions have been measured in terms of relative pseudorapidity (Δη) for charged particle pairs at the BNL Relativistic Heavy Ion Collider from Au + Au collisions at sNN=7.7GeV to 200 GeV using the STAR detector. These results are compared with balance functions measured at the CERN Large Hadron Collider from Pb + Pb collisions at sNN=2.76TeV by the ALICE Collaboration. The width of the balance function decreases as the collisions become more central and as the beam energy is increased. In contrast, the widths of the balance functions calculated using shuffled events show little dependence on centrality or beam energy and are larger than the observed widths. Balance function widths calculated using events generated by UrQMD are wider than the measured widths in central collisions and show little centrality dependence. The measured widths of the balance functions in central collisions are consistent with the delayed hadronization of a deconfined quark gluon plasma (QGP). The narrowing of the balance function in central collisions at sNN=7.7 GeV implies that a QGP is still being created at this relatively low energy. © 2016 American Physical Society.942CNPq, Conselho Nacional de Desenvolvimento Científico e TecnológicoMinistry of Education and Science of the Russian FederationMOE, Ministry of Education of the People's Republic of ChinaMOST, Ministry of Science and Technology of the People's Republic of ChinaNRF-2012004024, National Research FoundationNSF, National Stroke FoundationConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

    J/ψ polarization in p+p collisions at s=200 GeV in STAR

    Get PDF
    AbstractWe report on a polarization measurement of inclusive J/ψ mesons in the di-electron decay channel at mid-rapidity at 2<pT<6 GeV/c in p+p collisions at s=200 GeV. Data were taken with the STAR detector at RHIC. The J/ψ polarization measurement should help to distinguish between different models of the J/ψ production mechanism since they predict different pT dependences of the J/ψ polarization. In this analysis, J/ψ polarization is studied in the helicity frame. The polarization parameter λθ measured at RHIC becomes smaller towards high pT, indicating more longitudinal J/ψ polarization as pT increases. The result is compared with predictions of presently available models
    corecore