5,798 research outputs found

    Evolution of magnetic Dirac bosons in a honeycomb lattice

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    We examine the presence and evolution of magnetic Dirac nodes in the Heisenberg honeycomb lattice. Using linear spin theory, we evaluate the collinear phase diagram as well as the change in the spin dynamics with various exchange interactions. We show that the ferromagnetic structure produces bosonic Dirac and Weyl points due to the competition between superexchange interactions. Furthermore, it is shown that the criteria for magnetic Dirac nodes are coupled to the magnetic structure and not the overall crystal symmetry, where the breaking of inversion symmetry greatly affects the antiferromagnetic configurations. The tunability of the nodal points through variation of the exchange parameters leads to the possibility of controlling Dirac symmetries through an external manipulation of the orbital interactions.Comment: 9 pages, 7 figures, Submitted for publicatio

    Is the ground state of Yang-Mills theory Coulombic?

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    We study trial states modelling the heavy quark-antiquark ground state in SU(2) Yang-Mills theory. A state describing the flux tube between quarks as a thin string of glue is found to be a poor description of the continuum ground state; the infinitesimal thickness of the string leads to UV artifacts which suppress the overlap with the ground state. Contrastingly, a state which surrounds the quarks with non-abelian Coulomb fields is found to have a good overlap with the ground state for all charge separations. In fact, the overlap increases as the lattice regulator is removed. This opens up the possibility that the Coulomb state is the true ground state in the continuum limit.Comment: 10 pages, 9 .eps figure

    Simplified mathematical modeling of the distribution process of licuroside and glycyram between the extractant and Glycyrrhizae radices

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    Theoretical development of the extraction process is an important task for further modeling and calculation of optimal conditions for extraction of biologically active compounds from the plant raw material. The aim of the study was to propose and test a theoretical model to describe the process of Licuroside and Glycyram distribution between the solid phase of Glycyrrhiza radices and the extractant. For studies, we used Glycyrrhiza radices (Liquorice roots). For extraction, we used plant raw material with particle size of 0.1-0.5 mm, and ethanol-water solution 70 % v/v was used as an extractan

    The pp-Daugavet property for function spaces

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    A natural extension of the Daugavet property for pp-convex Banach function spaces and related classes is analysed. As an application, we extend the arguments given in the setting of the Daugavet property to show that no reflexive space falls into this class

    A Socio-Spatial Approach to Enable Inclusive Well-Being in Cities: A Case Study of Birmingham, UK

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    This article examines density and deprivation, the two important parameters that define health and well-being in cities. Discussions are drawn from a case study conducted in Birmingham in four neighborhoods characterized by their different population density and deprivation levels. Data were collected through questionnaires developed from a set of subjective well-being measures and built environment audits, based on the Irvine Minnesota Inventory that evaluates the quality of streets and walkability in neighborhoods. The inferences from the study support the need for linking health, planning, policy and design research and decision-making to the socio-spatial practices of people, impacting well-being at the everyday level. The findings provide a holistic approach health and well-being research and suggests a conceptual framework for inclusive well-being in cities, which signifies the role of social and spatial parameters in determining peoples’ health and well-being. The study also highlights the lack of interdisciplinary research in understanding the association between well-being and social and behavioral practices in diverse communities

    Development of the technology for obtaining a thick extract from fruits of milk thistle with the stage of ultrasonic influence

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    This article presents the results of the development of technology for obtaining a thick extract of milk thistle fruits using ultrasonic treatment of plant material and extractant in the soaking stage. Materials and Methods: For the research, crushed fruits of milk thistle from “Biokor” Ltd, Penza, Russia, series 011216 were used, and the shelf life is 2 year

    Higher-order Abel equations: Lagrangian formalism, first integrals and Darboux polynomials

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    A geometric approach is used to study a family of higher-order nonlinear Abel equations. The inverse problem of the Lagrangian dynamics is studied in the particular case of the second-order Abel equation and the existence of two alternative Lagrangian formulations is proved, both Lagrangians being of a non-natural class (neither potential nor kinetic term). These higher-order Abel equations are studied by means of their Darboux polynomials and Jacobi multipliers. In all the cases a family of constants of the motion is explicitly obtained. The general n-dimensional case is also studied

    Study of antimicrobial activity and technology optimization of Calendulae flos galenicals

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    The article presents materials on optimization of manufacture technology for Calendulae flos galenicals with medium level of antibacterial activity. For antibacterial study of extracts, we used agar well diffusion method. In our research, we utilized six test-strain microorganisms: E. coli ATCC 25922, S. aureus ATCC 25923, P. vulgaris ATCC 4636, P. aeruginosa ATCC 27853, C. albicans ATCC 885/653, and B. subtilis ATCC 6633. We have found that the maximum level of extracts’ antimicrobial activity is achieved in the range of ethanol content in the extractant from 70 to 97 % v/

    Two-Fermion Production in Electron-Positron Collisions

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    This report summarizes the results of the two-fermion working group of the LEP2-MC workshop, held at CERN from 1999 to 2000. Recent developments in the theoretical calculations of the two fermion production process in the electron-positron collision at LEP2 center of the mass energies are reported. The Bhabha process and the production of muon, tau, neutrino and quark pairs is covered. On the basis of comparison of various calculations, theoretical uncertainties are estimated and compared with those needed for the final LEP2 data analysis. The subjects for the further studies are identified.Comment: 2-fermion working group report of the LEP2 Monte Carlo Workshop 1999/2000, 113 pages, 24 figures, 35 table
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