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

A Pilot Study to Measure Upper Extremity H-reflexes Following Neuromuscular Electrical Stimulation Therapy after Stroke

Upper extremity (UE) hemiparesis persists after stroke, limiting hand function. Neuromuscular electrical stimulation (NMES) is an effective intervention to improve UE recovery, although the underlying mechanisms are not fully understood. Our objective was to establish a reliable protocol to measure UE agonist–antagonist forearm monosynaptic reflexes in a pilot study to determine if NMES improves wrist function after stroke. We established the between-day reliability of the H-reflex in the extensor carpi radialis longus (ECRL) and flexor carpi radialis (FCR) musculature for individuals with prior stroke (n = 18). The same-day generation of ECRL/FCR H-reflex recruitment curves was well tolerated, regardless of age or UE spasticity. The between-day reliability of the ECRL H-reflex was enhanced above FCR, similar to healthy subjects [20], with the Hmax the most reliable parameter quantified in both muscles. H-reflex and functional measures following NMES show the potential for NMES-induced increases in ECRL Hmax, but confirmation requires a larger clinical study. Our initial results support the safe, easy, and efficacious use of in-home NMES, and establish a potential method to measure UE monosynaptic reflexes after stroke

Generation of entangled photon-pairs from a single quantum dot embedded in a planar photonic-crystal cavity

We present a formal theory of single quantum-dot coupling to a planar photonic crystal that supports quasi-degenerate cavity modes, and use this theory to describe, and optimize, entangled-photon-pair generation via the biexciton-exciton cascade. In the generated photon pairs, either both photons are spontaneously emitted from the dot, or one photon is emitted from the biexciton spontaneously and the other is emitted via the leaky-cavity mode. In the strong-coupling regime, the generated photon pairs can be maximally entangled, in qualitative agreement with the simple dressed-state predictions of Johne {\em et al.} [Phys. Rev. Lett. vol. 100, 240404 (2008)]. We derive useful and physically-intuitive analytical formulas for the spectrum of the emitted photon pairs in the presence of exciton and biexciton broadening, which is necessary to connect to experiments, and demonstrate the clear failure of using a dressed-state approach. We also present a method for calculating and optimizing the entanglement between the emitted photons, which can account for post-sample spectral filtering. Pronounced entanglement values of greater than 80% are demonstrated using experimentally achievable parameters, even without spectral filtering.Comment: 5pages 4 fi

Observation of a One-Dimensional Spin-Orbit Gap in a Quantum Wire

Understanding the flow of spins in magnetic layered structures has enabled an increase in data storage density in hard drives over the past decade of more than two orders of magnitude1. Following this remarkable success, the field of 'spintronics' or spin-based electronics is moving beyond effects based on local spin polarisation and is turning its attention to spin-orbit interaction (SOI) effects, which hold promise for the production, detection and manipulation of spin currents, allowing coherent transmission of information within a device. While SOI-induced spin transport effects have been observed in two- and three-dimensional samples, these have been subtle and elusive, often detected only indirectly in electrical transport or else with more sophisticated techniques. Here we present the first observation of a predicted 'spin-orbit gap' in a one-dimensional sample, where counter-propagating spins, constituting a spin current, are accompanied by a clear signal in the easily-measured linear conductance of the system.Comment: 10 pages, 5 figures, supplementary informatio

SEASAT: A satellite scatterometer illumination times of selected in situ sites

A list of times that the SEASAT A Satellite Scatterometer (SASS) illuminated from directly above or directly abeam, selected surface sites where in situ winds were measured is provided. The list is ordered by the Greenwich Mean Time (GMT) of the midpoint of the illumination period (hit time) for a given surface site. The site identification, the orbit number and the direction from the subtrack in which the truth lies are provided. The accuracy of these times depends in part upon the ascending node times, which are estimated to be within +.1 sec, and on the illumination time relative to the ascending node, which is estimated to be within +6 seconds. The uncertainties in the times provided were judged to be sufficiently small to allow efficient and accurate extraction of SASS and in situ data at the selected surface sites. The list contains approximately six thousand hit times from 61 geographically dispersed sites

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)

A Time-Orbiting Potential Trap for Bose-Einstein Condensate Interferometry

We describe a novel atom trap for Bose-Einstein condensates of 87Rb to be used in atom interferometry experiments. The trap is based on a time-orbiting potential waveguide. It supports the atoms against gravity while providing weak confinement to minimize interaction effects. We observe harmonic oscillation frequencies omega_x, omega_y, omega_z as low as 2 pi times (6.0,1.2,3.3) Hz. Up to 2 times 10^4 condensate atoms have been loaded into the trap, at estimated temperatures as low as 850 pK. We anticipate that interferometer measurement times of 1 s or more should be achievable in this device.Comment: 9 pages, 3 figure

Analytical modeling of circuit aerodynamics in the new NASA Lewis wind tunnel

Rehabilitation and extention of the capability of the altitude wind tunnel (AWT) was analyzed. The analytical modeling program involves the use of advanced axisymmetric and three dimensional viscous analyses to compute the flow through the various AWT components. Results for the analytical modeling of the high speed leg aerodynamics are presented; these include: an evaluation of the flow quality at the entrance to the test section, an investigation of the effects of test section bleed for different model blockages, and an examination of three dimensional effects in the diffuser due to reentry flow and due to the change in cross sectional shape of the exhaust scoop

Parameter estimation of coalescing supermassive black hole binaries with LISA

Laser Interferometer Space Antenna (LISA) will routinely observe coalescences of supermassive black hole (BH) binaries up to very high redshifts. LISA can measure mass parameters of such coalescences to a relative accuracy of $10^{-4}-10^{-6}$, for sources at a distance of 3 Gpc. The problem of parameter estimation of massive nonspinning binary black holes using post-Newtonian (PN) phasing formula is studied in the context of LISA. Specifically, the performance of the 3.5PN templates is contrasted against its 2PN counterpart using a waveform which is averaged over the LISA pattern functions. The improvement due to the higher order corrections to the phasing formula is examined by calculating the errors in the estimation of mass parameters at each order. The estimation of the mass parameters ${\cal M}$ and $\eta$ are significantly enhanced by using the 3.5PN waveform instead of the 2PN one. For an equal mass binary of $2\times10^6M_\odot$ at a luminosity distance of 3 Gpc, the improvement in chirp mass is $\sim 11$ and that of $\eta$ is $\sim 39$. Estimation of coalescence time $t_c$ worsens by 43%. The improvement is larger for the unequal mass binary mergers. These results are compared to the ones obtained using a non-pattern averaged waveform. The errors depend very much on the location and orientation of the source and general conclusions cannot be drawn without performing Monte Carlo simulations. Finally the effect of the choice of the lower frequency cut-off for LISA on the parameter estimation is studied.Comment: 12 pages, 5 figures (eps) significant revision, accepted for publication in Phys. Rev. D. Matches with the published versio