225 research outputs found
Hopf algebraic structure of the parabosonic and parafermionic algebras and paraparticle generalization of the Jordan Schwinger map
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 BiTeSe investigated using -detected nuclear magnetic relaxation and resonance of Li
We report measurements on the high temperature ionic and low temperature
electronic properties of the 3D topological insulator BiTeSe using
ion-implanted Li -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 Li diffusion with an
activation energy eV and attempt frequency s 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 -emitter Li
We report measurements of the Meissner screening profile in a Nb(300
nm)/AlO thin film using Li -detected nuclear magnetic
resonance (-NMR). The NMR probe Li was ion-implanted into the Nb
film at energies 20 keV, corresponding to mean stopping depths
comparable to Nb's magnetic penetration depth . Li's strong
dipole-dipole coupling with the host 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 . From a fit of the data to a model
accounting for its dependence on temperature, magnetic field, and
Li implantation energy, we obtained a magnetic penetration depth
= 51.5(22) nm, consistent with a relatively short carrier
mean-free-path = 18.7(29) nm typical of similarly prepared Nb films. The
results presented here constitute an important step towards using Li
-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 Li Nuclear Magnetic Resonance in Highly Oriented Pyrolytic Graphite
We report -detected nuclear magnetic resonance of ultra-dilute
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 Li in ZnO
We report on the stability and magnetic state of ion implanted Li in
single crystals of the semiconductor ZnO using -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
Li 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
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
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.
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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