Magnetic induction plasma engine Final report

Wall interaction reduction in magnetic induction plasma accelerato

Filling of magnetic-impurity-induced gap in topological insulators by potential scattering

We show that the energy gap induced by ferromagnetically aligned magnetic impurities on the surface of a topological insulator can be filled, due to scattering off the non-magnetic potential of the impurities. In both a continuum surface model and a three-dimensional tight-binding lattice model, we find that the energy gap disappears already at weak potential scattering as impurity resonances add spectral weight at the Dirac point. This can help explain seemingly contradictory experimental results as to the existence of a gap.Comment: 5 pages, 4 figures. Published versio

Domain walls in a chiral d-wave superconductor on the honeycomb lattice

We perform a fully self-consistent study of domain walls between different chiral domains in chiral $d_{x^2-y^2} \pm id_{xy}-wave superconductors with an underlying honeycomb lattice structure. We investigate domain walls along all possible armchair and zigzag directions and with a finite global phase shift across the domain wall, in addition to the change of chirality. For armchair domain walls we find the lowest domain wall energy at zero global phase shift, while the most favorable zigzag domain wall has a finite global phase shift dependent on the doping level. Below the van Hove singularity the armchair domain wall is most favorable, while at even higher doping the zigzag domain wall has the lowest energy. The domain wall causes a local suppression of the superconducting order parameter, with the superconducting recovery length following a universal curve for all domain walls. Moreover, we always find four subgap states crossing zero energy and well localized to the domain wall. However, the details of their energy spectrum vary notably, especially with the global phase shift across the domain wall.Comment: 8 pages, 8 figure

Priority monism and essentiality of fundamentality: a reply to Steinberg

Steinberg has recently proposed an argument against Schaffer’s priority monism. The argument assumes the principle of Necessity of Monism, which states that if priority monism is true, then it is necessarily true. In this paper, I argue that Steinberg’s objection can be eluded by giving up Necessity of Monism for an alternative principle, that I call Essentiality of Fundamentality, and that such a principle is to be preferred to Necessity of Monism on other grounds as well

Magnon Dirac materials

We demonstrate how a Dirac-like magnon spectrum is generated for localized magnetic moments forming a two-dimensional honeycomb lattice. The Dirac crossing point is proven to be robust against magnon-magnon interactions, as these only shift the spectrum. Local defects induce impurity resonances near the Dirac point, as well as magnon Friedel oscillations. The energy of the Dirac point is controlled by the exchange coupling, and thus a two-dimensional array of magnetic dots is an experimentally feasible realization of Dirac magnons with tunable dispersion.Comment: 6 pages, 2 figures - article as publishe

The crux of the matter: did the ABC's Catalyst program change statin use in Australia?

This article argues that the ABC’s Catalyst program criticising statins affected people’s willingness to take these drugs. Abstract Objectives: To examine the impact of a two-part special edition of the Australian Broadcasting Corporation\u27s science journalism program Catalyst (titled Heart of the matter), aired in October 2013, that was critical of HMG-CoA reductase inhibitors (“statins”). Design, setting and participants: Population-based interrupted time-series analysis of a 10% sample of Australian long-term concessional beneficiaries who were dispensed statins under the Pharmaceutical Benefits Scheme (about 51% of all people who were dispensed a statin between 1 July 2009 and 30 June 2014); dispensing of proton pump inhibitors (PPIs) was used as a comparator. Main outcome measures: Change in weekly dispensings and discontinuation of use of statins and PPIs, adjusting for seasonal and long-term trends, overall and (for statins only) stratified by the use of cardiovascular and diabetes medicines. Results: In our sample, 191 833 people were dispensed an average of 26 946 statins weekly. Following the Catalyst program, there was a 2.60% (95% CI, 1.40%–3.77%; P < 0.001) reduction in statin dispensing, equivalent to 14 005 fewer dispensings Australia-wide every week. Dispensing decreased by 6.03% (95% CI, 3.73%–8.28%; P < 0.001) for people not dispensed other cardiovascular and diabetes medicines and 1.94% (0.42%–3.45%; P = 0.01) for those dispensed diabetes medicines. In the week the Catalyst program aired, there was a 28.8% (95% CI, 15.4%–43.7%; P < 0.001) increase in discontinuation of statin use, which decayed by 9% per week. An estimated 28 784 additional Australians ceased statin treatment. Discontinuation occurred regardless of the use of other cardiovascular and diabetes medicines. There were no significant changes in PPI use after the Catalyst program. Conclusions: Following airing of the Catalyst program, there was a temporary increase in discontinuation and a sustained decrease in overall statin dispensing. Up until 30 June 2014, there were 504 180 fewer dispensings of statins, and we estimate this to have affected 60 897 people

Interfacial Effects of Al-Termination on Spin Transport in Magnetic Tunnel Junctions

Experiments have shown that the tunneling current in a Co/Al$_2$O$_3$ magnetic tunneling junction (MTJ) is positively spin polarized, opposite to what is intuitively expected from standard tunneling theory which gives the spin polarization as exclusively dependent on the density of states (DOS) at $E_F$ of the Co layers. Here we report theoretical results that give a positive tunneling spin polarization and tunneling magnetoresistance (TMR) that is in good agreement with experiments. From density functional theory (DFT) calculations, an Al-rich interface MTJ with atomic-level disorder is shown to have a positively polarized DOS near the interface. We also provide an atomic model calculation which gives insights into the source of the positive polarization. A layer and spin dependent effective mass model, using values extracted from the DFT results, is then used to calculate the tunneling current, which shows positive spin polarization. Finally, we calculate the TMR from the tunneling spin polarization which shows good agreement with experiments

Feasibility of Photofrin II as a radiosensitizing agent in solid tumors - Preliminary results

Background: Photofrin II has been demonstrated to serve as a specific and selective radiosensitizing agent in in vitro and in vivo tumor models. We aimed to investigate the feasibility of a clinical application of Photofrin II. Material and Methods: 12 patients were included in the study (7 unresectable solid tumors of the pelvic region, 3 malignant gliomas, 1 recurrent oropharyngeal cancer, 1 recurrent adenocarcinoma of the sphenoid sinus). The dose of ionizing irradiation was 30-50.4 Gy; a boost irradiation of 14 Gy was added for the pelvic region. All patients were intravenously injected with 1 mg/kg Photofrin II 24 h prior to the commencement of radiotherapy. Magnetic resonance imaging (MRI) controls and in some cases positron emission tomography (PET) were performed in short intervals. The mean follow-up was 12.9 months. Results: No major adverse events were noted. Minor adverse events consisted of mild diarrhea, nausea and skin reactions. A complete remission was observed in 4/12 patients. A reduction in local tumor volume of > 45% was achieved in 4/12 patients. Stable disease was observed in 4/12 patients. 1 patient showed local disease progression after 5 months. Conclusion: The early follow-up results are encouraging regarding the feasibility of the application of Photofrin II as a radiosensitizing agent

Dirac materials

A wide range of materials, like d-wave superconductors, graphene, and topological insulators, share a fundamental similarity: their low-energy fermionic excitations behave as massless Dirac particles rather than fermions obeying the usual Schrodinger Hamiltonian. This emergent behavior of Dirac fermions in condensed matter systems defines the unifying framework for a class of materials we call "Dirac materials''. In order to establish this class of materials, we illustrate how Dirac fermions emerge in multiple entirely different condensed matter systems and we discuss how Dirac fermions have been identified experimentally using electron spectroscopy techniques (angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy). As a consequence of their common low-energy excitations, this diverse set of materials shares a significant number of universal properties in the low-energy (infrared) limit. We review these common properties including nodal points in the excitation spectrum, density of states, specific heat, transport, thermodynamic properties, impurity resonances, and magnetic field responses, as well as discuss many-body interaction effects. We further review how the emergence of Dirac excitations is controlled by specific symmetries of the material, such as time-reversal, gauge, and spin-orbit symmetries, and how by breaking these symmetries a finite Dirac mass is generated. We give examples of how the interaction of Dirac fermions with their distinct real material background leads to rich novel physics with common fingerprints such as the suppression of back scattering and impurity-induced resonant states.Comment: Review article accepted in Adv. Phys. 77 page