Bondi-Sachs Energy-Momentum for the CMC Initial Value Problem

The constraints on the asymptotic behavior of the conformal factor and conformal extrinsic curvature imposed by the initial value equations of general relativity on constant mean extrinsic curvature (CMC) hypersurfaces are analyzed in detail. We derive explicit formulas for the Bondi-Sachs energy and momentum in terms of coefficients of asymptotic expansions on CMC hypersurfaces near future null infinity. Precise numerical results for the Bondi-Sachs energy, momentum, and angular momentum are used to interpret physically Bowen-York solutions of the initial value equations on conformally flat CMC hypersurfaces of the type obtained earlier by Buchman et al. [Phys. Rev. D 80:084024 (2009)].Comment: version to be published in Phys. Rev.

Structural Basis for the Anomalously Low Spontaneous Polarisation Values of the Polar Phase of Sr1-xCaxTiO3 (x=0.02, 0.04): Evidence for a Ferrielectric Ordering

Full pattern Le-Bail refinement using x-ray powder diffraction profiles of Sr1-xCaxTiO3 for x=0.02, 0.04 in the temperature range 12 to 300 K reveals anomalies in the unit cell parameters at 170, 225 K due to an antiferrodistortive (cubic to tetragonal I4/mcm) phase transition and at ~32, ~34 K due to a transition to a polar phase (tetragonal I4/mcm to orthorhombic Ic2m), respectively. The lower transition temperatures obtained by us are in excellent agreement with those reported on the basis of the dielectric studies by Bednorz and Muller, [10] who attributed these to ferroelectric transition. Rietveld analysis of the diffraction profiles of the polar phase reveals off-centre displacements of both Sr2+/Ca2+ and Ti4+ ions in the X-Y plane along pseudocubic directions, in agreement with the experimentally reported direction of easy polarization by Bednorz and Muller, but the resulting dipole moments are shown to be ferrielectrically coupled in the neighbouring (001) planes along the [001] direction leading to anomalously low values of the spontaneous polarization at 12K.Comment: 5 pages, 4 figures and 1 tabl

Black hole initial data on hyperboloidal slices

We generalize Bowen-York black hole initial data to hyperboloidal constant mean curvature slices which extend to future null infinity. We solve this initial value problem numerically for several cases, including unequal mass binary black holes with spins and boosts. The singularity at null infinity in the Hamiltonian constraint associated with a constant mean curvature hypersurface does not pose any particular difficulties. The inner boundaries of our slices are minimal surfaces. Trumpet configurations are explored both analytically and numerically.Comment: version for publication in Phys. Rev.

γ-synuclein is a novel player in the control of body lipid metabolism

Peer reviewedPublisher PD

An Evaluation of a Nerve Block Protocol in Patients with Hip Fractures

BACKGROUND/PURPOSE: Pain management for hip fracture patients in the time before surgery is crucial. Literature highlights the success of local, single injection nerve blocks to aid in preoperative pain management. A local hospital implemented a preoperative, single injection nerve block protocol in March 2018. This quality improvement project investigated: (1) organization protocol compliance, and (2) if the preoperative single injection nerve block protocol reduces hip fracture pain, use of systemic opioid analgesics, decreases incidence of adverse opioid effects, and reduces cost of care. SUBJECTS: Patients ages 18 and older admitted with the primary diagnosis of an operable isolated hip fracture (n=100). METHODS: Data measures were extracted from the electronic health records and the trauma registry and were entered into REDCap encrypted software. ANALYSIS: Data was analyzed using SAS statistical software to verify whether the intervention was successful in meeting cost, quality, and compliance measures. RESULTS: Results were not statistically significant in reducing oral and intravenous narcotic use before (p=0.80; p=0.39) and after (p=0.23; p=0.10) surgical correction, nor was there statistically significant change in adverse effects (p=0.10) and length of stay (p=0.90). However, there was a statistically significant reduction in preoperative pain levels following nerve block administration (p\u3c0.0001). Protocol compliance was 66% over seven months. CONCLUSION: The results of this project were consistent with the literature; nerve block injection may reduce preoperative pain for patients with an operable hip fracture. Further investigation is needed to determine if narcotic use and length of stay could be impacted if time variability in nerve block administration were reduced and if protocol compliance were increased