Post-Newtonian Models of Binary Neutron Stars

Using an energy variational method, we calculate quasi-equilibrium configurations of binary neutron stars modeled as compressible triaxial ellipsoids obeying a polytropic equation of state. Our energy functional includes terms both for the internal hydrodynamics of the stars and for the external orbital motion. We add the leading post-Newtonian (PN) corrections to the internal and gravitational energies of the stars, and adopt hybrid orbital terms which are fully relativistic in the test-mass limit and always accurate to PN order. The total energy functional is varied to find quasi-equilibrium sequences for both corotating and irrotational binaries in circular orbits. We examine how the orbital frequency at the innermost stable circular orbit depends on the polytropic index n and the compactness parameter GM/Rc^2. We find that, for a given GM/Rc^2, the innermost stable circular orbit along an irrotational sequence is about 17% larger than the innermost secularly stable circular orbit along the corotating sequence when n=0.5, and 20% larger when n=1. We also examine the dependence of the maximum neutron star mass on the orbital frequency and find that, if PN tidal effects can be neglected, the maximum equilibrium mass increases as the orbital separation decreases.Comment: 53 pages, LaTex, 9 figures as 10 postscript files, accepted by Phys. Rev. D, replaced version contains updated reference

Do compensation plans with performance targets provide better incentives?

YesGuided by academic literature, industry practice and policy recommendations, we analyze a wide range of option and restricted stock plans with exercise and vesting conditions that may be contingent on stock price performance. To assess the effectiveness of these plans at attracting and providing incentives to executives, we create compensation plans with fixed firm cost and executive valuation and calculate their expected total lifetime incentives. We show that performance vesting targets provide the least cost effective incentives, performance exercise targets provide the largest risk incentives, option plans are generally superior to restricted stock plans, and calendar vesting is only efficient up to a maximum of three years. Performance exercise targets can increase the expected total lifetime incentives provided by compensation plans, but in general, standard options with short vesting periods provide the most cost effective pay-for-performance incentives

Coalescing Binary Neutron Stars

Coalescing compact binaries with neutron star or black hole components provide the most promising sources of gravitational radiation for detection by the LIGO/VIRGO/GEO/TAMA laser interferometers now under construction. This fact has motivated several different theoretical studies of the inspiral and hydrodynamic merging of compact binaries. Analytic analyses of the inspiral waveforms have been performed in the Post-Newtonian approximation. Analytic and numerical treatments of the coalescence waveforms from binary neutron stars have been performed using Newtonian hydrodynamics and the quadrupole radiation approximation. Numerical simulations of coalescing black hole and neutron star binaries are also underway in full general relativity. Recent results from each of these approaches will be described and their virtues and limitations summarized.Comment: Invited Topical Review paper to appear in Classical and Quantum Gravity, 35 pages, including 5 figure

Non-invasive methods : the applicability of unmanned aerial vehicle (UAV) technology for recording fossilised footprints

Hominin fossilised trackways are commonly used to reconstruct locomotory behaviour and to characterise track-maker biometrics. They are the most direct representation of hominin locomotion available, yet the fossil sites are susceptible to extreme cases of erosion and weathering, often resulting in the destruction of the fossil beds, as was the case at two prehistoric footprint sites: Formby Point and Happisburgh, UK. Footprints can also be found in easily deformable sediments where the excavator can unintentionally trample and destroy the prints, as occurred at Formby Point, UK. There is the need for non-destructive methods to be identified that can rapidly record the fossil area before further damage can occur to the fossil beds. Because current methods of 3D data capture (laser scanning or photogrammetry) can be invasive (i.e., the excavator is often required to trample the sediment layer during data capture), non-invasive methods need to be explored to circumvent issues in advertently destroying fossil material. In this project, a series of experiments using non-invasive methods tested the applicability of Unmanned Aerial Vehicle (UAV) technology combined with photogrammetry to rapidly and accurately record footprints before further damage to the fossil interface occurred. Various flight paths, UAVs, cameras and capture types (video versus camera stills) were incorporated to test the accuracy in minute depth reconstruction and subsequent 3D mesh creation of small, intricate detail. Shape and size, the consequence of poorly reconstructed depth dimensionality of surfaces, were found to be affected by flight path and by the height of the UAV, indicating that the most optimal method of recording tracks is to use a handheld DSLR camera following a circular or rastered flight path. Despite attempts to utilise UAV technology, inaccurate reconstructions of footprint topography were produced. Although UAV technology produced unreliable reconstructions, UAVs remain a technological solution when sites may be at immediate risk of destruction, as was the case at Happisburgh, UK. The deployment of UAV technology will permit the digital preservation of fossil material which would otherwise be lost

Predicting in vivo starch digestibility coefficients in newly weaned piglets from in vitro assessment of diets using multivariate analysis.

The study was based on correlating a dataset of in vivo mean starch digestibility coefficients obtained in the immediate post-weaning phase of piglets with a range of dietary in vitro variables. The paper presents a model that predicts (R2 0·71) in vivo average starch digestibility coefficients in the 0·5 small-intestinal region of newly weaned piglets fed cereal-based diets using seven in vitro variables describing starch properties that are fundamentally associated with the quality of feed materials, i.e. hydration, structure and amylolytic digestion. The variables were: Rapid Visco Analyser (RVA; measures the viscosity of materials when sheared under defined hydration and temperature regimens); RVA end viscosity; RVA (gelatinisation) peak viscosity; ΔH (gelatinisation enthalpy that provides an estimate of helical order or degree of crystallinity in starch); water solubility index (WSI; that denotes the amount of soluble polysaccharides released from starch granules to the aqueous phase); grain endogenous amylase (concentration of endogenous α-amylase in cereals, assessed by pasting cereal flours in 25 g of AgNO3, an amylase inhibitor v. water using RVA)

Safety of Everolimus With Reduced Calcineurin Inhibitor Exposure in De Novo Kidney Transplants: An Analysis From the Randomized TRANSFORM Study

BACKGROUND: The safety profiles of standard therapy versus everolimus with reduced-exposure calcineurin inhibitor (CNI) therapy using contemporary protocols in de novo kidney transplant recipients have not been compared in detail. METHODS: TRANSFORM was a randomized, international trial in which de novo kidney transplant patients were randomized to everolimus with reduced-exposure CNI (N = 1014) or mycophenolic acid (MPA) with standard-exposure CNI (N = 1012), both with induction and corticosteroids. RESULTS: Within the safety population (everolimus 1014, MPA 1012), adverse events with a suspected relation to study drug occurred in 62.9% versus 59.2% of patients given everolimus or MPA, respectively (P = 0.085). Hyperlipidemia, interstitial lung disease, peripheral edema, proteinuria, stomatitis/mouth ulceration, thrombocytopenia, and wound healing complications were more frequent with everolimus, whereas diarrhea, nausea, vomiting, leukopenia, tremor, and insomnia were more frequent in the MPA group. The incidence of viral infections (17.2% versus 29.2%; P < 0.001), cytomegalovirus (CMV) infections (8.1% versus 20.1%; P < 0.001), CMV syndrome (13.6% versus 23.0%, P = 0.044), and BK virus (BKV) infections (4.3% versus 8.0%, P < 0.001) were less frequent with everolimus. CMV infection was less common with everolimus versus MPA after adjusting for prophylaxis therapy in the D+/R- subgroup (P < 0.001). Study drug was discontinued more frequently due to rejection or impaired healing with everolimus, and more often due to BKV infection or BKV nephropathy with MPA. CONCLUSIONS: De novo everolimus with reduced-exposure CNI yielded a comparable incidence, though a distinctly different pattern, of adverse events versus current standard of care. Both regimens are safe and effective, yet their distinct profiles may enable tailoring for individual kidney transplant recipients.status: publishe