Creating Weyl nodes and controlling their energy by magnetization rotation

As they do not rely on the presence of any crystal symmetry, Weyl nodes are robust topological features of an electronic structure that can occur at any momentum and energy. Acting as sinks and sources of Berry curvature, Weyl nodes have been predicted to strongly affect the transverse electronic response, like in the anomalous Hall or Nernst effects. However, to observe large anomalous effects the Weyl nodes need to be close to or at the Fermi-level, which implies the band structure must be tuned by an external parameter, e.g. chemical doping or pressure. Here we show that in a ferromagnetic metal tuning of the Weyl node energy and momentum can be achieved by rotation of the magnetization. Taking Co$_3$Sn$_2$S$_2$ as an example, we use electronic structure calculations based on density-functional theory to show that not only new Weyl fermions can be created by canting the magnetization away from the easy axis, but also that the Weyl nodes can be driven exactly to the Fermi surface. We also show that the dynamics in energy and momentum of the Weyl nodes strongly affect the calculated anomalous Hall and Nernst conductivities.Comment: Supp. Material adde

Generally Covariant Conservative Energy-Momentum for Gravitational Anyons

We obtain a generally covariant conservation law of energy-momentum for gravitational anyons by the general displacement transform. The energy-momentum currents have also superpotentials and are therefore identically conserved. It is shown that for Deser's solution and Clement's solution, the energy vanishes. The reasonableness of the definition of energy-momentum may be confirmed by the solution for pure Einstein gravity which is a limit of vanishing Chern-Simons coulping of gravitational anyons.Comment: 12 pages, Latex, no figure

Preparing athletes and teams for the Olympic Games: experiences and lessons learned from the world's best sport psychologists

As part of an increased effort to understand the most effective ways to psychologically prepare athletes and teams for Olympic competition, a number of sport psychology consultants have offered best-practice insights into working in this context. These individual reports have typically comprised anecdotal reflections of working with particular sports or countries; therefore, a more holistic approach is needed so that developing practitioners can have access to - and utilise - a comprehensive evidence-base. The purpose of this paper is to provide a panel-type article, which offers lessons and advice for the next generation of aspiring practitioners on preparing athletes and teams for the Olympic Games from some of the world’s most recognised and experienced sport psychologists. The sample comprised 15 sport psychology practitioners who, collectively, have accumulated over 200 years of first-hand experience preparing athletes and/or teams from a range of nations for six summer and five winter Olympic Games. Interviews with the participants revealed 28 main themes and 5 categories: Olympic stressors, success and failure lessons, top tips for neophyte practitioners, differences within one’s own consulting work, and multidisciplinary consulting. It is hoped that the findings of this study can help the next generation of sport psychologists better face the realities of Olympic consultancy and plan their own professional development so that, ultimately, their aspirations to be the world’s best can become a reality

Prevalence and Concordance of oral and Genital Hpv By Sexual orientation among Us Men

The objective of our study was to describe oral and genital human papillomavirus (HPV) infection prevalence and concordance by sexual orientation among US men using a nationally representative sample. We conducted a retrospective cross-sectional analysis of the 2013-2016 National Health and Nutrition Examination Survey. The survey conducts a physical examination and collects oral rinse and genital swab specimens; demographic and health behaviors are self-reported. We used descriptive statistics and multivariate regression models to estimate HPV infection prevalence and the likelihood of HPV infection, respectively. All analyses were adjusted for National Health and Nutrition Examination Survey design and weights, and statistical significance was tested at a 2-sided P value of less than .05. Men who have sex with men had a statistically significantly higher prevalence of oral HPV (high-risk, 9-valent, 4-valent, and HPV 16 and 18), genital HPV (9-valent, 4-valent, and HPV 16 and 18), and concordant oral and genital HPV (high-risk and 9-valent) infections compared with heterosexual men. Improved HPV prevention among men is needed

Superalgebra and Conservative Quantities in N=1 Self-dual Supergravity

The N=1 self-dual supergravity has SL(2,C) and the left-handed and right -handed local supersymmetries. These symmetries result in SU(2) charges as the angular-momentum and the supercharges. The model possesses also the invariance under the general translation transforms and this invariance leads to the energy-momentum. All the definitions are generally covariant . As the SU(2) charges and the energy-momentum we obtained previously constituting the 3-Poincare algebra in the Ashtekar's complex gravity, the SU(2) charges, the supercharges and the energy-momentum here also restore the super-Poincare algebra, and this serves to support the reasonableness of their interpretations.Comment: 18 pages, Latex, no figure

Pulmonary Hypertension in Portugal: First Data from a Nationwide Registry

Introduction. Pulmonary arterial hypertension (PAH) is a rare disease that must be managed in specialized centers; therefore, the availability of epidemiological national data is critical. Methods. We conducted a prospective, observational, and multicenter registry with a joint collaboration from five centers from Portugal and included adult incident patients with PAH or chronic thromboembolic pulmonary hypertension (CTEPH). Results. Of the 79 patients enrolled in this study, 46 (58.2%) were classified as PAH and 33 patients (41.8%) as CTEPH. PAH patients had a mean age of 43.4 ± 16.4 years. Idiopathic PAH was the most common etiology (37%). At presentation, PAH patients had elevated right atrial pressure (RAP) (7.7 ± 5.9 mmHg) and mean pulmonary vascular resistance (11.4 ± 6.5 Wood units), with a low cardiac index (2.7 ± 1.1 L·min−1·m−2); no patient was under selective pulmonary vasodilators; however, at follow-up, most patients were on single (50%), double (28%), or triple (9%) combination vasodilator therapy. One-year survival was 93.5%, similar to CTEPH patients (93.9%), that were older (60.0 ± 12.5 years) and had higher RAP (11.0 ± 5.2 mmHg, ). Conclusions. We describe for the first time nationwide data on the diagnosis, management, and prognosis of PAH and CTEPH patients in Portugal. Clinical presentation and outcomes are comparable with those reported on other national registries.The authors thank Actelion Portugal Lda. for supporting the development of the dedicated software (PAHTool) and data entr

Dirac fermions and flat bands in the ideal kagome metal FeSn.

A kagome lattice of 3d transition metal ions is a versatile platform for correlated topological phases hosting symmetry-protected electronic excitations and magnetic ground states. However, the paradigmatic states of the idealized two-dimensional kagome lattice-Dirac fermions and flat bands-have not been simultaneously observed. Here, we use angle-resolved photoemission spectroscopy and de Haas-van Alphen quantum oscillations to reveal coexisting surface and bulk Dirac fermions as well as flat bands in the antiferromagnetic kagome metal FeSn, which has spatially decoupled kagome planes. Our band structure calculations and matrix element simulations demonstrate that the bulk Dirac bands arise from in-plane localized Fe-3d orbitals, and evidence that the coexisting Dirac surface state realizes a rare example of fully spin-polarized two-dimensional Dirac fermions due to spin-layer locking in FeSn. The prospect to harness these prototypical excitations in a kagome lattice is a frontier of great promise at the confluence of topology, magnetism and strongly correlated physics

Topological flat bands in frustrated kagome lattice CoSn

Electronic flat bands in momentum space, arising from strong localization of electrons in real space, are an ideal stage to realize strong correlation phenomena. In certain lattices with built-in geometrical frustration, electronic confinement and flat bands can naturally arise from the destructive interference of electronic hopping pathways. Such lattice-borne flat bands are often endowed with nontrivial topology if combined with spin-orbit coupling, while their experimental realization in condensed matter system has been elusive so far. Here, we report the direct observation of topological flat bands in the vicinity of the Fermi level in frustrated kagome system CoSn, using angle-resolved photoemission spectroscopy and band structure calculations. The flat band manifests itself as a dispersionless electronic excitation along the G-M high symmetry direction, with an order of magnitude lower bandwidth (below 150 meV) compared to the Dirac bands originating from the same orbitals. The frustration-driven nature of the flat band is directly confirmed by the real-space chiral d-orbital texture of the corresponding effective Wannier wave functions. Spin-orbit coupling opens a large gap of 80 meV at the quadratic band touching point between the Dirac and flat bands, endowing a nonzero Z2 topological invariant to the flat band in the two-dimensional Brillouin zone. Our observation of lattice-driven topological flat band opens a promising route to engineer novel emergent phases of matter at the crossroad between strong correlation physics and electronic topology.Comment: 19 pages, 4 figure

Creating Weyl nodes and controlling their energy by magnetization rotation

As they do not rely on the presence of any crystal symmetry, Weyl nodes are robust topological features of an electronic structure that can occur at any momentum and energy. Acting as sinks and sources of Berry curvature, Weyl nodes have been predicted to strongly affect the transverse electronic response, like in the anomalous Hall or Nernst effects. However, to observe large anomalous effects the Weyl nodes need to be close to or at the Fermi level, which implies the band structure must be tuned by an external parameter, e.g., chemical doping. Here we show that in a ferromagnetic metal tuning of the Weyl node energy and momentum can be achieved by rotation of the magnetization. First, taking as example the elementary magnet hcp-Co, we use electronic structure calculations based on density-functional theory to show that by canting the magnetization away from the easy axis, Weyl nodes can be driven exactly to the Fermi surface. Second, we show that the same phenomenology applies to the kagome ferromagnet Co3Sn2S2, in which we additionally show how the dynamics in energy and momentum of the Weyl nodes affects the calculated anomalous Hall and Nernst conductivities. Our results highlight how the intrinsic magnetic anisotropy can be used to engineer Weyl physics