40,072 research outputs found
Meteoroid detector
A meteoroid detector is described which uses, a cold cathode discharge tube with a gas-pressurized cell in space for recording a meteoroid puncture of the cell and for determining the size of the puncture
Topological Insulator Magnetic Tunnel Junctions: Quantum Hall Effect and Fractional Charge via Folding
We provide a characterization of tunneling between coupled topological
insulators in 2D and 3D under the influence of a ferromagnetic layer. We
explore conditions for such systems to exhibit integer quantum Hall physics and
localized fractional charge, also taking into account interaction effects for
the 2D case. We show that the effects of tunneling are topologically equivalent
to a certain deformation or folding of the sample geometry. Our key advance is
the realization that the quantum Hall or fractional charge physics can appear
in the presence of only a \emph{single} magnet unlike previous proposals which
involve magnetic domain walls on the surface or edges of topological insulators
respectively. We give illustrative topological folding arguments to prove our
results and show that for the 2D case our results are robust even in the
presence of interactions.Comment: 5 pages, 2 figure
Orbital evolution of a test particle around a black hole: higher-order corrections
We study the orbital evolution of a radiation-damped binary in the extreme
mass ratio limit, and the resulting waveforms, to one order beyond what can be
obtained using the conservation laws approach. The equations of motion are
solved perturbatively in the mass ratio (or the corresponding parameter in the
scalar field toy model), using the self force, for quasi-circular orbits around
a Schwarzschild black hole. This approach is applied for the scalar model.
Higher-order corrections yield a phase shift which, if included, may make
gravitational-wave astronomy potentially highly accurate.Comment: 4 pages, 3 Encapsulated PostScript figure
Implementing fully relativistic hydrodynamics in three dimensions
We report on our numerical implementation of fully relativistic hydrodynamics
coupled to Einstein's field equations in three spatial dimensions. We briefly
review several steps in our code development, including our recasting of
Einstein's equations and several tests which demonstrate its advantages for
numerical integrations. We outline our implementation of relativistic
hydrodynamics, and present numerical results for the evolution of both stable
and unstable Oppenheimer-Volkov equilibrium stars, which represent a very
promising first test of our code.Comment: 5 Pages, 4 Figures, submitted to Proceedings of the 8th Canadian
Conference on General Relativity and Relativistic Astrophysic
Sexual Orientation Differences in the Relationship Between Victimization and Hazardous Drinking Among Women in the National Alcohol Survey
This study examined relationships between past experiences of victimization (sexual abuse and physical abuse in childhood, sexual abuse and physical abuse in adulthood, and lifetime victimization) and hazardous drinking among sexual minority women compared to exclusively heterosexual women. Data were from 11,169 women responding to sexual identity and sexual behavior questions from three National Alcohol Survey waves: 2000 (n = 3,880), 2005 (n = 3,464), and 2010 (n = 3,825). A hazardous drinking index was constructed from five dichotomous variables (5+ drinking in the past year, drinking two or more drinks daily, drinking to intoxication in the past year, two or more lifetime dependence symptoms, and two or more lifetime drinking-related negative consequences). Exclusively heterosexual women were compared with three groups of sexual minority women: lesbian, bisexual, and women who identified as heterosexual but reported same-sex partners. Each of the sexual minority groups reported significantly higher rates of lifetime victimization (59.1% lesbians, 76% bisexuals, and 64.4% heterosexual women reporting same-sex partners) than exclusively heterosexual women (42.3%). Odds for hazardous drinking among sexual minority women were attenuated when measures of victimization were included in the regression models. Sexual minority groups had significantly higher odds of hazardous drinking, even after controlling for demographic and victimization variables: lesbian (OR [sub]adj[sub] = 2.0, CI = 1.1–3.9, p \u3c .01; bisexual (OR [sub]adj[sub] = 1.8, CI = 1.0–3.3, p \u3c .05; heterosexual with same-sex partners (ORadj = 2.7; CI = 1.7–4.3, p \u3c .001). Higher rates of victimization likely contribute to, but do not fully explain, higher rates of hazardous drinking among sexual minority women. (PsycINFO Database Record (c) 2013 APA, all rights reserved) (journal abstract)
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