Wormhole Effect in a Strong Topological Insulator

An infinitely thin solenoid carrying magnetic flux Phi (a `Dirac string') inserted into an ordinary band insulator has no significant effect on the spectrum of electrons. In a strong topological insulator, remarkably, such a solenoid carries protected gapless one-dimensional fermionic modes when Phi=hc/2e. These modes are spin-filtered and represent a distinct bulk manifestation of the topologically non-trivial insulator. We establish this `wormhole' effect by both general qualitative considerations and by numerical calculations within a minimal lattice model. We also discuss the possibility of experimental observation of a closely related effect in artificially engineered nanostructures.Comment: 4 pages, 3 figures. For related work and info visit http://www.physics.ubc.ca/~fran

Topological Anderson Insulator in Three Dimensions

Disorder, ubiquitously present in solids, is normally detrimental to the stability of ordered states of matter. In this letter we demonstrate that not only is the physics of a strong topological insulator robust to disorder but, remarkably, under certain conditions disorder can become fundamentally responsible for its existence. We show that disorder, when sufficiently strong, can transform an ordinary metal with strong spin-orbit coupling into a strong topological `Anderson' insulator, a new topological phase of quantum matter in three dimensions.Comment: 5 pages, 2 figures. For related work and info visit http://www.physics.ubc.ca/~franz

Clear air turbulence

Research on forecasting, detection, and incidents of clear air turbulenc

Adaptive mesh refinement with spectral accuracy for magnetohydrodynamics in two space dimensions

We examine the effect of accuracy of high-order spectral element methods, with or without adaptive mesh refinement (AMR), in the context of a classical configuration of magnetic reconnection in two space dimensions, the so-called Orszag-Tang vortex made up of a magnetic X-point centered on a stagnation point of the velocity. A recently developed spectral-element adaptive refinement incompressible magnetohydrodynamic (MHD) code is applied to simulate this problem. The MHD solver is explicit, and uses the Elsasser formulation on high-order elements. It automatically takes advantage of the adaptive grid mechanics that have been described elsewhere in the fluid context [Rosenberg, Fournier, Fischer, Pouquet, J. Comp. Phys. 215, 59-80 (2006)]; the code allows both statically refined and dynamically refined grids. Tests of the algorithm using analytic solutions are described, and comparisons of the Orszag-Tang solutions with pseudo-spectral computations are performed. We demonstrate for moderate Reynolds numbers that the algorithms using both static and refined grids reproduce the pseudo--spectral solutions quite well. We show that low-order truncation--even with a comparable number of global degrees of freedom--fails to correctly model some strong (sup--norm) quantities in this problem, even though it satisfies adequately the weak (integrated) balance diagnostics.Comment: 19 pages, 10 figures, 1 table. Submitted to New Journal of Physic

Controlled release ibuprofen-poloxamer gel for epidural use - A pharmacokinetic study using microdialysis in pigs

In order to avoid the risks of sideeffects of epidural local anesthetics and opioids, the use of nonsteroidal anti-inflammatory drugs (NSAIDs) epidurally would be an interesting option of analgesic therapy. The fairly short duration of action of spinally administered NSAIDs, e.g., ibuprofen, may be prolonged by using controlled release poloxamer gel formulation. Using a microdialysis technique we studied the epidural and intrathecal pharmacokinetics of ibuprofen after its epidural administration as a poloxamer 407 formulation or a solution formulation. In addition, plasma ibuprofen concentrations were analyzed from central venous blood samples. Ibuprofen concentrations in the epidural space were significantly higher and longer lasting after the epidural gel injection compared with the epidural solution injection. The epidural AUC of ibuprofen was over threefold greater after epidural ibuprofen gel injection compared with the ibuprofen solution injection (p <0.001). The systemic absorption of ibuprofen from 25% poloxamer 407 gel was very low. The in situ forming poloxamer gel acted as a reservoir allowing targeted ibuprofen release at the epidural injection site and restricted ibuprofen molecules to a smaller spinal area. Ibuprofen diffusion from the epidural space to the intrathecal space was steady and prolonged. These results demonstrate that the use of epidurally injectable poloxamer gel can increase and prolong ibuprofen delivery from epidural space to the CSF enhancing thus ibuprofen entry into the central neuroaxis for spinal analgesia. Further toxicological and dose-finding studies are justified. (C) 2016 Elsevier B.V. All rights reserved.Peer reviewe

Self-similar structure and experimental signatures of suprathermal ion distribution in inertial confinement fusion implosions

The distribution function of suprathermal ions is found to be self-similar under conditions relevant to inertial confinement fusion hot-spots. By utilizing this feature, interference between the hydro-instabilities and kinetic effects is for the first time assessed quantitatively to find that the instabilities substantially aggravate the fusion reactivity reduction. The ion tail depletion is also shown to lower the experimentally inferred ion temperature, a novel kinetic effect that may explain the discrepancy between the exploding pusher experiments and rad-hydro simulations and contribute to the observation that temperature inferred from DD reaction products is lower than from DT at National Ignition Facility.Comment: Revised version accepted for publication in PRL. "Copyright (2015) by the American Physical Society.

Negotiated Development Denial Meets People\u27s Court: Del Monte Dunes Brings New Wildcards to Exactions Law

The United States Supreme Court Answered YES to the $1.45 million over exaction question for 1999. In City of Monterey v. Del Monte Dunes at Monterey Ltd., a unanimous court extended the scope of compensatory takings review beyond land dedication conditions into the realm of regulatory denial. Justice Kennedy\u27s opinion vitalized the legitimate state interests test from Agins v. City of Tiburon to sustain an inverse condemnation conclusion and damage award to the frustrated developer. A majority of the court also concurred that the trial court may delegate this takings conclusion to the jury under federal civil rights law. The activation of Agins\u27 substantive takings test in such challenges and the prospect of continued lay application of constitutional law to development restrictions add uncertain dimensions to exactions litigation at the millennium. In Del Monte Dunes, the Court also distinguished the instant development denial of an inverse condemnation claim from the land dedication conditions at issue in Dolan v. City of Tigard. This distinction enabled the unanimous Court to uphold the trial verdict based on Agins and avoid elements of the Ninth Circuit\u27s reasoning invoking the Dolan rough proportionality test. Other recent federal and state decisions also decline to extend Dolan\u27s applicability beyond individual land dedication development conditions to other forms of economic exactions. This year\u27s exactions and impact fee report focuses on Del Monte Dunes, namely its effects on negotiated development, trial practice, and on regulatory takings doctrine as defined by judges and juries in civil rights litigation

Negotiated Development Denial Meets People\u27s Court: Del Monte Dunes Brings New Wildcards to Exactions Law

The United States Supreme Court Answered YES to the $1.45 million over exaction question for 1999. In City of Monterey v. Del Monte Dunes at Monterey Ltd., a unanimous court extended the scope of compensatory takings review beyond land dedication conditions into the realm of regulatory denial. Justice Kennedy\u27s opinion vitalized the legitimate state interests test from Agins v. City of Tiburon to sustain an inverse condemnation conclusion and damage award to the frustrated developer. A majority of the court also concurred that the trial court may delegate this takings conclusion to the jury under federal civil rights law. The activation of Agins\u27 substantive takings test in such challenges and the prospect of continued lay application of constitutional law to development restrictions add uncertain dimensions to exactions litigation at the millennium. In Del Monte Dunes, the Court also distinguished the instant development denial of an inverse condemnation claim from the land dedication conditions at issue in Dolan v. City of Tigard. This distinction enabled the unanimous Court to uphold the trial verdict based on Agins and avoid elements of the Ninth Circuit\u27s reasoning invoking the Dolan rough proportionality test. Other recent federal and state decisions also decline to extend Dolan\u27s applicability beyond individual land dedication development conditions to other forms of economic exactions. This year\u27s exactions and impact fee report focuses on Del Monte Dunes, namely its effects on negotiated development, trial practice, and on regulatory takings doctrine as defined by judges and juries in civil rights litigation