Interpolating compact binary waveforms using the singular value decomposition

Compact binary systems with total masses between tens and hundreds of solar masses will produce gravitational waves during their merger phase that are detectable by second-generation ground-based gravitational-wave detectors. In order to model the gravitational waveform of the merger epoch of compact binary coalescence, the full Einstein equations must be solved numerically for the entire mass and spin parameter space. However, this is computationally expensive. Several models have been proposed to interpolate the results of numerical relativity simulations. In this paper we propose a numerical interpolation scheme that stems from the singular value decomposition. This algorithm shows promise in allowing one to construct arbitrary waveforms within a certain parameter space given a sufficient density of numerical simulations covering the same parameter space. We also investigate how similar approaches could be used to interpolate waveforms in the context of parameter estimation.Comment: 5 pages, 3 figures, presented at the joint 9th Edoardo Amaldi Conference on Gravitational Waves and 2011 Numerical Relativity - Data Analysis (NRDA) meetin

Spinal and Supraspinal Motor Control Predictors of Rate of Torque Development

During explosive movements and potentially injurious situations, the ability to rapidly generate torque is critical. Previous research has suggested that different phases of rate of torque development (RTD) are differentiately controlled. However, the extent to which supraspinal and spinal mechanisms predict RTD at different time intervals is unknown. RTD of the plantarflexors across various phases of contraction (i.e., 0–25, 0–50, 0–100, 0–150, 0–200, and 0–250 ms) was measured in 37 participants. The following predictor variables were also measured: (a) gain of the resting soleus H-reflex recruitment curve; (b) gain of the resting homonymous post-activation depression recruitment curve; (c) gain of the GABAergic presynaptic inhibition recruitment curve; (d) the level of postsynaptic recurrent inhibition at rest; (e) level of supraspinal drive assessed by measuring V waves; and (f) the gain of the resting soleus M wave. Stepwise regression analyses were used to determine which variables significantly predicted allometrically scaled RTD. The analyses indicated that supraspinal drive was the dominant predictor of RTD across all phases. Additionally, recurrent inhibition predicted RTD in all of the time intervals except 0–150 ms. These results demonstrate the importance of supraspinal drive and recurrent inhibition to RTD

CHANGES IN PRINCIPAL COMPONENT STRUCTURE OF COUNTERMOVEMENT JUMPS AFTER A VOLLEYBALL SEASON

The purpose of this study was to investigate changes in the principal component structure of countermovement jumps (CMJ) in female volleyball players over the course of a competitive season. Eleven NCAA Division I female volleyball players performed CMJs on a force plate before and after a competitive season. Discrete biomechanical variables were extracted from the force-time records of all CMJs and entered into a factor analysis. The analysis yielded two factors that could account for the biomechanical structure of the CMJs: a temporal and a force factor. Although no differences in factor scores were identified between pre- and post-season testing sessions, sub-group analysis highlighted large individual changes in temporal and force factor scores

Lacunar fractal photon sieves

We present a new family of diffractive lenses whose structure is based on the combination of two concepts: photon sieve and fractal zone plates with variable lacunarity. The focusing properties of different members of this family are examined. It is shown that the sieves provide a smoothing effect on the higher order foci of a conventional lacunar fractal zone plate. However, the characteristic self-similar axial response of the fractal zone plates is always preserved.Comment: 7 pages, 5 figure

GENERALIZED JOINT HYPERMOBILITY ALTERS FRONTAL PLANE KNEE JOINT LOADING IN FEMALE COLLEGIATE DIVISION 1 LACROSSE ATHLETES

Generalized joint hypermobility (GJH) has been defined as a form of joint laxity that affects an individual systemically, with 5-43% of individuals in the population affected. These individuals experience injuries at a higher frequency and severity than the normal population. The purpose of this investigation was to determine if female collegiate division I lacrosse players with GJH demonstrated different knee mechanics than matched controls. Kinematic and kinetic data were collected as participants performed a single leg land and cut task. The GJH group demonstrated greater peak internal knee adductor moments during landing and a trend toward greater knee extensor moments, which has been reported as a deleterious pattern of loading with increased risk for non-contact anterior cruciate ligament injuries

Direct comparison between potential landscape and local density of states in a disordered two-dimensional electron system

The local density of states (LDOS) of the adsorbate induced two-dimensional electron system (2DES) on n-InAs(110) is studied by low-temperature scanning tunneling spectroscopy. The LDOS exhibits irregular structures with fluctuation lengths decreasing with increasing energy. Fourier transformation reveals that the k-values of the unperturbed 2DES dominate the LDOS, but additional lower k-values contribute significantly. To clarify the origin of the additional k-space intensity, we measure the potential landscape of the same 2DES area with the help of the tip induced quantum dot. This allows to calculate the expected LDOS from the single particle Schroedinger equation and to directly compare it with the measured one. Reasonable correspondance between calculated and measured LDOS is found.Comment: 7 pages, 4 figures, submitted to PR

Characterization of immune response to neurofilament light in experimental autoimmune encephalomyelitis

PMCID: PMC3856490This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.PMCID: PMC385649