225 research outputs found

    Hopf algebraic structure of the parabosonic and parafermionic algebras and paraparticle generalization of the Jordan Schwinger map

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    The aim of this paper is to show that there is a Hopf structure of the parabosonic and parafermionic algebras and this Hopf structure can generate the well known Hopf algebraic structure of the Lie algebras, through a realization of Lie algebras using the parabosonic (and parafermionic) extension of the Jordan Schwinger map. The differences between the Hopf algebraic and the graded Hopf superalgebraic structure on the parabosonic algebra are discussed.Comment: 11 pages, LaTex2e fil

    Ionic and electronic properties of the topological insulator Bi2_2Te2_2Se investigated using β\beta-detected nuclear magnetic relaxation and resonance of 8^8Li

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    We report measurements on the high temperature ionic and low temperature electronic properties of the 3D topological insulator Bi2_2Te2_2Se using ion-implanted 8^8Li β\beta-detected nuclear magnetic relaxation and resonance. With implantation energies in the range 5-28 keV, the probes penetrate beyond the expected range of the topological surface state, but are still within 250 nm of the surface. At temperatures above ~150 K, spin-lattice relaxation measurements reveal isolated 8^8Li+^{+} diffusion with an activation energy EA=0.185(8)E_{A} = 0.185(8) eV and attempt frequency τ01=8(3)×1011\tau_{0}^{-1} = 8(3) \times 10^{11} s1^{-1} for atomic site-to-site hopping. At lower temperature, we find a linear Korringa-like relaxation mechanism with a field dependent slope and intercept, which is accompanied by an anomalous field dependence to the resonance shift. We suggest that these may be related to a strong contribution from orbital currents or the magnetic freezeout of charge carriers in this heavily compensated semiconductor, but that conventional theories are unable to account for the extent of the field dependence. Conventional NMR of the stable host nuclei may help elucidate their origin.Comment: 17 pages, 12 figures, submitted to Phys. Rev.

    Depth-resolved measurement of the Meissner screening profile in a niobium thin film from spin-lattice relaxation of the implanted β\beta-emitter 8^{8}Li

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    We report measurements of the Meissner screening profile in a Nb(300 nm)/Al2_{2}O3_{3} thin film using 8^{8}Li β\beta-detected nuclear magnetic resonance (β\beta-NMR). The NMR probe 8^{8}Li was ion-implanted into the Nb film at energies \leq 20 keV, corresponding to mean stopping depths comparable to Nb's magnetic penetration depth λ\lambda. 8^{8}Li's strong dipole-dipole coupling with the host 93^{93}Nb nuclei provided a "cross-relaxation" channel that dominated in low magnetic fields, which conferred indirect sensitivity to the local magnetic field via the spin-lattice relaxation (SLR) rate 1/T11/T_{1}. From a fit of the 1/T11/T_{1} data to a model accounting for its dependence on temperature, magnetic field, and 8^{8}Li+^{+} implantation energy, we obtained a magnetic penetration depth λ0\lambda_{0} = 51.5(22) nm, consistent with a relatively short carrier mean-free-path \ell = 18.7(29) nm typical of similarly prepared Nb films. The results presented here constitute an important step towards using 8^{8}Li β\beta-NMR to characterize bulk Nb samples with engineered surfaces, which are often used in the fabrication of particle accelerators.Comment: 16 pages, 4 figure

    Ion-Implanted 8^8Li Nuclear Magnetic Resonance in Highly Oriented Pyrolytic Graphite

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    We report β\beta-detected nuclear magnetic resonance of ultra-dilute 8^{8}Li+^{+} implanted in highly oriented pyrolytic graphite (HOPG). The absence of motional narrowing and diffusional spin-lattice relaxation implies Li+^+ is not appreciably mobile up to 400 K, in sharp contrast to the highly lithiated stage compounds. However, the relaxation is remarkably fast and persists down to cryogenic temperatures. Ruling out extrinsic paramagnetic impurities and intrinsic ferromagnetism, we conclude the relaxation is due to paramagnetic centers correlated with implantation. While the resulting effects are not consistent with a Kondo impurity, they also differ from free paramagnetic centers, and we suggest that a resonant scattering approach may account for much of the observed phenomenology

    Nuclear magnetic resonance of ion implanted 8^8Li in ZnO

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    We report on the stability and magnetic state of ion implanted 8^8Li in single crystals of the semiconductor ZnO using β\beta-detected nuclear magnetic resonance. At ultradilute concentrations, the spectra reveal distinct Li sites from 7.6 to 400 K. Ionized shallow donor interstitial Li is stable across the entire temperature range, confirming its ability to self-compensate the acceptor character of its (Zn) substitutional counterpart. Above 300 K, spin-lattice relaxation indicates the onset of correlated local motion of interacting defects, and the spectra show a site change transition from disordered configurations to substitutional. Like the interstitial, the substitutional shows no resolved hyperfine splitting, indicating it is also fully ionized above 210 K. The electric field gradient at the interstitial 8^8Li exhibits substantial temperature dependence with a power law typical of non-cubic metals.Comment: 15 pages and 11 figure

    International, multidisciplinary Delphi consensus recommendations on non-pharmacological interventions for fibromyalgia

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    Funding Information: The Republic of Turkey Ministry of National Education for the PhD studentship. Publisher Copyright: © 2022 The Author(s)Objectives: To develop evidence-based expert recommendations for non-pharmacological treatments for pain, fatigue, sleep problems, and depression in fibromyalgia. Methods: An international, multidisciplinary Delphi exercise was conducted. Authors of EULAR and the Canadian Fibromyalgia Guidelines Group, members of the American Pain Society and clinicians with expertise in fibromyalgia were invited. Participants were asked to select non-pharmacological interventions that could be offered for specific fibromyalgia symptoms and to classify them as either core or adjunctive treatments. An evidence summary was provided to aid the decision making. Items receiving >70% votes were accepted, those receiving <30% votes were rejected and those obtaining 30-70% votes were recirculated for up to two additional rounds. Results: Seventeen experts participated (Europe (n = 10), North America (n = 6), and Israel (n = 1)) in the Delphi exercise and completed all three rounds. Aerobic exercise, education, sleep hygiene and cognitive behavioural therapy were recommended as core treatments for all symptoms. Mind-body exercises were recommended as core interventions for pain, fatigue and sleep problems. Mindfulness was voted core treatment for depression, and adjunctive treatment for other symptoms. Other interventions, namely music, relaxation, hot bath, and local heat were voted as adjunctive treatments, varying between symptoms. Conclusions: This study provided evidence-based expert consensus recommendations on non-pharmacological treatments for fibromyalgia that may be used to individualise treatments in clinical practice targeting the diverse symptoms associated with fibromyalgia.publishersversionepub_ahead_of_prin

    Academic artisans in the research university

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    In the changing context of universities, organisational structures for teaching and research problematize academic roles. This paper draws on a critical realist analysis of surveys and interviews with academics from universities in England and Australia. It identifies important academic work, not captured simply in descriptions of teaching or research. It shows that many academics, who are not research high flyers nor award-winning teachers, carry out this essential work which contributes to the effective functioning of their universities. That work is referred to as academic artisanal work and the people who do it as academic artisans. Characteristics and examples of academic artisans are presented and the nature of artisanal work is explored. Implications for higher education management and for future studies are discussed. The paper points to an urgent need to better understand the complex nature of academic work

    International criteria for electrocardiographic interpretation in athletes: Consensus statement.

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    Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly, advanced by a growing body of scientific data and investigations that both examine proposed criteria sets and establish new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington (USA), to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD
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