33,304 research outputs found

    Particle Tracking Studies Using Dynamical Map Created from Finite Element Solution of the EMMA Cell

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    The un­con­ven­tion­al size and the pos­si­bil­i­ty of trans­verse dis­place­ment of the mag­nets in the EMMA non-scal­ing FFAG mo­ti­vates a care­ful study of par­ti­cle be­hav­ior with­in the EMMA ring. The mag­net­ic field map of the dou­blet cell is com­put­ed using a Fi­nite El­e­ment Method solver; par­ti­cle mo­tion through the field can then be found by nu­mer­i­cal in­te­gra­tion, using (for ex­am­ple) OPERA, or ZGOUBI. How­ev­er, by ob­tain­ing an an­a­lyt­i­cal de­scrip­tion of the mag­net­ic field (by fit­ting a Fouri­er-Bessel se­ries to the nu­mer­i­cal data) and using a dif­fer­en­tial al­ge­bra code, such as COSY, to in­te­grate the equa­tions of mo­tion, it is pos­si­ble to pro­duce a dy­nam­i­cal map in Tay­lor form. This has the ad­van­tage that, after once com­put­ing the dy­nam­i­cal map, mul­ti-turn track­ing is far more ef­fi­cient than re­peat­ed­ly per­form­ing nu­mer­i­cal in­te­gra­tions. Also, the dy­nam­i­cal map is small­er (in terms of com­put­er mem­o­ry) than the full mag­net­ic field map; this al­lows dif­fer­ent con­fig­u­ra­tions of the lat­tice, in terms of mag­net po­si­tions, to be rep­re­sent­ed very eas­i­ly using a set of dy­nam­i­cal maps, with in­ter­po­la­tion be­tween the co­ef­fi­cients in dif­fer­ent maps*

    A generalized bayesian inference method for constraining the interiors of super Earths and sub-Neptunes

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    We aim to present a generalized Bayesian inference method for constraining interiors of super Earths and sub-Neptunes. Our methodology succeeds in quantifying the degeneracy and correlation of structural parameters for high dimensional parameter spaces. Specifically, we identify what constraints can be placed on composition and thickness of core, mantle, ice, ocean, and atmospheric layers given observations of mass, radius, and bulk refractory abundance constraints (Fe, Mg, Si) from observations of the host star's photospheric composition. We employed a full probabilistic Bayesian inference analysis that formally accounts for observational and model uncertainties. Using a Markov chain Monte Carlo technique, we computed joint and marginal posterior probability distributions for all structural parameters of interest. We included state-of-the-art structural models based on self-consistent thermodynamics of core, mantle, high-pressure ice, and liquid water. Furthermore, we tested and compared two different atmospheric models that are tailored for modeling thick and thin atmospheres, respectively. First, we validate our method against Neptune. Second, we apply it to synthetic exoplanets of fixed mass and determine the effect on interior structure and composition when (1) radius, (2) atmospheric model, (3) data uncertainties, (4) semi-major axes, (5) atmospheric composition (i.e., a priori assumption of enriched envelopes versus pure H/He envelopes), and (6) prior distributions are varied. Our main conclusions are: [...]Comment: Astronomy & Astrophysics, 597, A37, 17 pages, 11 figure

    Two flavors of dynamical quarks on anisotropic lattices

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    We report on our study of two-flavor full QCD on anisotropic lattices using O(a)O(a)-improved Wilson quarks coupled with an RG-improved glue. The bare gauge and quark anisotropies corresponding to the renormalized anisotropy ξ=as/at=2\xi=a_s/a_t = 2 are determined as functions of β\beta and κ\kappa, which covers the region of spatial lattice spacings as0.28a_s\approx 0.28--0.16 fm and mPS/mV0.6m_{PS}/m_V\approx 0.6--0.9. The calibrations of the bare anisotropies are performed with the Wilson loop and the meson dispersion relation at 4 lattice cutoffs and 5--6 quark masses. Using the calibration results we calculate the meson mass spectrum and the Sommer scale r0r_0. We confirm that the values of r0r_0 calculated for the calibration using pseudo scalar and vector meson energy momentum dispersion relation coincide in the continuum limit within errors. This work serves to lay ground toward studies of heavy quark systems and thermodynamics of QCD including the extraction of the equation of state in the continuum limit using Wilson-type quark actions.Comment: 16 pages, 23 figures, Version accepted for publication in Physical Review

    Undergraduate antimicrobial stewardship training for pharmacy students: Creating a foundation for containment of antimicrobial resistance in South Africa

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    To the Editor: The inappropriate and excessive use of antimicrobial agents has cultivated the development and progression of antimicrobial resistance worldwide, which has been recognised as a threat to global health and safety.[1] In response to this alarming growth in antimicrobial resistance, antimicrobial stewardship initiatives, which aim to improve the judicious use of antimicrobial agents, have gained global support.[2] The Antimicrobial Resistance Strategy Framework in South Africa (SA) recognises the education of healthcare professionals as a strategy for containment of antimicrobial resistance in SA.[3

    Perturbative renormalization factors in domain-wall QCD with improved gauge actions

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    We evaluate renormalization factors of the domain-wall fermion system with various improved gauge actions at one loop level. The renormalization factors are calculated for quark wave function, quark mass, bilinear quark operators, three- and four-quark operators in modified minimal subtraction (MS-bar) scheme with the dimensional reduction(DRED) as well as the naive dimensional regularization(NDR). We also present detailed results in the mean field improved perturbation theory.Comment: 44 page

    Flavor Singlet Meson Mass in the Continuum Limit in Two-Flavor Lattice QCD

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    We present results for the mass of the eta-prime meson in the continuum limit for two-flavor lattice QCD, calculated on the CP-PACS computer, using a renormalization-group improved gauge action, and Sheikholeslami and Wohlert's fermion action with tadpole-improved csw. Correlation functions are measured at three values of the coupling constant beta corresponding to the lattice spacing a approx. 0.22, 0.16, 0.11 fm and for four values of the quark mass parameter kappa corresponding to mpi over mrho approx. 0.8, 0.75, 0.7 and 0.6. For each beta, kappa pair, 400-800 gauge configurations are used. The two-loop diagrams are evaluated using a noisy source method. We calculate eta-prime propagators using local sources, and find that excited state contributions are much reduced by smearing. A full analysis for the smeared propagators gives metaprime=0.960(87)+0.036-0.248 GeV, in the continuum limit, where the second error represents the systematic uncertainty coming from varying the functional form for chiral and continuum extrapolations.Comment: 9 pages, 19 figures, 4 table

    Essential micro-foundations for contemporary business operations: top management tangible competencies, relationship-based business networks and environmental sustainability

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    Although various studies have emphasized linkages between firm competencies, networks and sustainability at organizational level, the links between top management tangible competencies (e.g., contemporary relevant quantitative-focused education such as big data analytics and data-driven applications linked with the internet of things, relevant experience and analytical business applications), relationship-based business networks (RBNs) and environmental sustainability have not been well established at micro-level, and there is a literature gap in terms of investigating these relationships. This study examines these links based on the unique data collected from 175 top management representatives (chief executive officers and managing directors) working in food import and export firms headquartered in the UK and New Zealand. Our results from structural equation modelling indicate that top management tangible competencies (TMTCs) are the key determinants for building RBNs, mediating the correlation between TMTCs and environmental sustainability. Directly, the competencies also play a vital role towards environmental practices. The findings further depict that relationship-oriented firms perform better compared to those which focus less on such networks. Consequently, our findings provide a deeper understanding of the micro-foundations of environmental sustainability based on TMTCs rooted in the resource-based view and RBNs entrenched in the social network theory. We discuss the theoretical and practical implications of our findings, and we provide suggestions for future research

    Non-visualization of lung markings below hemidiaphragm in subtle subpulmonic effusion: an old sign resuscitated

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    To assess the lack of visibility of vascular markings under the hemidiaphragm on a frontal chest radiograph as a sign of pleural effusion, fifteen patients were collected showing this sign. Pleural effusion was diagnosed by ultrasound, comparison with previous or subsequent chest x-ray or computed tomography. Patients in the study group exhibited this sign in the absence of the classical signs of pleural effusion. In the control group, lack of visibility of blood vessels was observed in only 4.2% cases. Non-visualization of vascular markings below the hemidiaphragm should alert the interpreter to the possible presence of pleural effusion and a lateral or decubitus view or ultrasound examination may be carried out to rule out effusion

    Relativistic Quantum Games in Noninertial Frames

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    We study the influence of Unruh effect on quantum non-zero sum games. In particular, we investigate the quantum Prisoners' Dilemma both for entangled and unentangled initial states and show that the acceleration of the noninertial frames disturbs the symmetry of the game. It is shown that for maximally entangled initial state, the classical strategy C (cooperation) becomes the dominant strategy. Our investigation shows that any quantum strategy does no better for any player against the classical strategies. The miracle move of Eisert et al (1999 Phys. Rev. Lett. 83 3077) is no more a superior move. We show that the dilemma like situation is resolved in favor of one player or the other.Comment: 8 Pages, 2 figures, 2 table
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