Gravitating monopoles in SU(3) gauge theory

We consider the Einstein-Yang-Mills-Higgs equations for an SU(3) gauge group in a spherically symmetric ansatz. Several properties of the gravitating monopole solutions are obtained an compared with their SU(2) counterpart.Comment: 7 pages, Latex, 3 figure

An Attempt to Construct the Standard Model with Monopoles

We construct a model in which stable magnetic monopoles have magnetic charges that are identical to the electric charges on leptons and quarks and the colored monopoles are confined by strings in color singlets.Comment: 10 pages; LaTeX Added clarifying remarks, a Comment on the scattering of particles, acknowledgements and references. Version to be publishe

Regulatory Taking: A Contract Approach

This Article begins by defining the parameters of the fifth amendment\u27s taking clause. The Article then reviews the various tests used in determining whether governmental action constitutes a taking, and discusses the recent Supreme Court decisions within the framework of case law as it has evolved since the Court\u27s 1922 landmark decision, Pennsylvania Coal Co. v. Mahon. Finally, the Article suggests a formula based on well-established contract principles for analyzing the impact of land use regulation on private property interests

A systematic review and computational modelling analysis of unilateral montages in electroconvulsive therapy

Objective: To examine the clinical outcomes of ECT unilateral placements compared in prior studies and apply insights from computational modelling to understand differences between placements. Methods: PubMed, Embase, Scopus and PsycINFO and reference lists were systematically searched for studies of depressed patients where two unilateral placements were compared and clinical outcomes were reported. Computational modelling was done to generate electric field maps for each unilateral placement identified in the systematic review. Results: A total of 29 studies met criteria for inclusion. Eight studies reported efficacy outcomes and 23 studies reported cognitive outcomes. Most studies found no significant difference in efficacy between right unilateral (RUL) and left unilateral (LUL) ECT, and no difference was found between temporo-parietal and fronto-temporal ECT. For the majority of studies, RUL placements had better verbal anterograde memory outcomes compared with the LUL placements. There was some evidence suggestive of cognitive advantages for fronto-frontal and fronto-parietal placements relative to temporo-parietal ECT. Conclusions: For efficacy, studies mainly focused on the comparison of right vs. left hemispheric stimulation, with the available evidence suggesting no substantive difference. RUL placements tended to have better verbal anterograde memory outcomes relative to LUL placements, though limited differences were found between the RUL placements

Is there a monopole problem?

We investigate the high temperature behavior of SU(5) in its minimal version. We show that there exists a range of parameters of the Higgs potential for which the symmetry remains broken at high temperature, thus avoiding the phase transition that gives rise to the overproduction of monopoles . We also show that in such scenario the thermal production of monopoles can be suppressed in a wide range of parameters, keeping their number density below the cosmological limits.Comment: Latex, 12 pages, revised version as appeared in Physical Review Letters. Minor corrections, comments and two references adde

Effects of modifying the electrode placement and pulse width on cognitive side effects with unilateral ECT: A pilot randomised controlled study with computational modelling

Background: The electrode placement and pulse width for electroconvulsive therapy (ECT) are important treatment parameters associated with ECT related retrograde memory side-effects. Modification of these parameters with right unilateral (RUL) ECT may have utility for further reducing these side-effects. Objective: This study explored use of the frontoparietal (FP) placement for reducing retrograde memory side effects with ECT. We hypothesised that superior retrograde memory outcomes would occur with FP compared to temporoparietal (TP) placement and with ultrabrief (UB: 0.3 ms) compared to brief pulse (BP: 1.0 ms) width ECT. Methods: In this randomised cross-over, double-blinded study, participants received a single treatment of BP TP, BP FP, UB TP and UB FP ECT. Neuropsychological testing was conducted prior to and immediately following each treatment. Computational modelling was conducted to explore associations between E-fields in regions-of-interest associated with memory. Results: Nine participants completed the study. The FP placement was not superior to TP for retrograde memory outcomes. For both electrode placements UB pulse width was associated with significantly better visual retrograde memory compared to BP (p <.05). With TP ECT, higher E-fields in regions-of-interest were significantly associated with greater visual retrograde memory side-effects (hippocampi: r = −0.77, p =.04; inferior frontal gyri: r = −0.92, p <.01; middle frontal gyri: r = −0.84, p =.02). Conclusions: Modification of pulse-width had greater effects than electrode placement for reducing retrograde memory side-effects with RUL ECT. Preliminary findings suggested that higher E-fields may be associated with greater cognitive side-effects with ECT

Features of Motion Around Global Monopole in Asymptotically dS/AdS Spacetime

In this paper, we study the motion of test particle and light around the Global Monopole in asymptotically dS/AdS spacetime. The motion of a test particle and light in the exterior region of the global monopole in dS/AdS spacetime has been investigated. Although the test particle's motion is quite different from the case in asymptotically flat spacetime, the behaviors of light(null geodesic) remain unchanged except a energy(frequency) shift. Through a phase-plane analysis, we prove analytically that the existence of a periodic solution to the equation of motion for a test particle will not be altered by the presence of cosmological constant and the deficit angle, whose presence only affects the position and type of the critical point on the phase plane. We also show that the apparent capture section of the global monopole in dS/AdS spacetime is quite different from that in flat spacetime.Comment: 15 pages, 4 PS figures, accepted for publication in Class. Quantum Gra

Global Monopole in Asymptotically dS/AdS Spacetime

In this paper, we investigate the global monopole in asymptotically dS/Ads spacetime and find that the mass of the monopole in the asymptotically dS spacetime could be positive if the cosmological constant is greater than a critical value. This shows that the gravitational field of the global monopole could be attractive or repulsive depending on the value of the cosmological constant.Comment: 5 pages, 1 figure, to appear in Phys. Rev.

Cratering Soil by Impinging Jets of Gas, with Application to Landing Rockets on Planetary Surfaces

Several physical mechanisms are involved in excavating granular materials beneath a vertical jet of gas. These occur, for example, beneath the exhaust plume of a rocket landing on the soil of the Moon or Mars. A series of experiments and simulations have been performed to provide a detailed view of the complex gas/soil interactions. Measurements have also been taken from the Apollo lunar landing videos and from photographs of the resulting terrain, and these help to demonstrate how the interactions extrapolate into the lunar environment. It is important to understand these processes at a fundamental level to support the ongoing design of higher-fidelity numerical simulations and larger-scale experiments. These are needed to enable future lunar exploration wherein multiple hardware assets will be placed on the Moon within short distances of one another. The high-velocity spray of soil from landing spacecraft must be accurately predicted and controlled lest it erosively damage the surrounding hardware

SU(5) monopoles and non-abelian black holes

We construct spherically and axially symmetric monopoles in SU(5) Yang-Mills-Higgs theory both in flat and curved space as well as spherical and axial non-abelian, ''hairy'' black holes. We find that in analogy to the SU(2) case, the flat space monopoles are either non-interacting (in the BPS limit) or repelling. In curved space, however, gravity is able to overcome the repulsion for suitable choices of the Higgs coupling constants and the gravitational coupling. In addition, we confirm that indeed all qualitative features of (gravitating) SU(2) monopoles are found as well in the SU(5) case. For the non-abelian black holes, we compare the behaviour of the solutions in the BPS limit with that for non-vanishing Higgs self-coupling constants.Comment: 14 Revtex pages, 9 PS-figure