Gravitational-wave phasing for low-eccentricity inspiralling compact binaries to 3PN order

[abridged] Although gravitational radiation causes inspiralling compact binaries to circularize, a variety of astrophysical scenarios suggest that binaries might have small but nonnegligible orbital eccentricities when they enter the low-frequency bands of ground and space-based gravitational-wave detectors. If not accounted for, even a small orbital eccentricity can cause a potentially significant systematic error in the mass parameters of an inspiralling binary. Gravitational-wave search templates typically rely on the quasi-circular approximation, which provides relatively simple expressions for the gravitational-wave phase to 3.5 post-Newtonian (PN) order. The quasi-Keplerian formalism provides an elegant but complex description of the post-Newtonian corrections to the orbits and waveforms of inspiralling binaries with any eccentricity. Here we specialize the quasi-Keplerian formalism to binaries with low eccentricity. In this limit the non-periodic contribution to the gravitational-wave phasing can be expressed explicitly as simple functions of frequency or time, with little additional complexity beyond the well-known formulas for circular binaries. These eccentric phase corrections are computed to 3PN order and to leading order in the eccentricity for the standard PN approximants. For a variety of systems these eccentricity corrections cause significant corrections to the number of gravitational wave cycles that sweep through a detector's frequency band. This is evaluated using several measures, including a modification of the useful cycles. We also evaluate the role of periodic terms that enter the phasing and discuss how they can be incorporated into some of the PN approximants. While the eccentric extension of the PN approximants is our main objective, this work collects a variety of results that may be of interest to others modeling eccentric relativistic binaries.Comment: 49 pages, 4 figures. Submitted to Phys. Rev. D. Supplementary materials available at http://link.aps.org/supplemental/10.1103/PhysRevD.93.124061. V2: minor updates to match published versio

Designing Dual-Class Sunsets: The Case for a Transfer-Centered Approach

Dual-class stock (DCS) structures, and their implications for managerial accountability and corporate governance more broadly, have become prevalent concerns for corporate lawyers and policymakers. Recent academic and practitioner debates on DCS have tended to focus less on the general merits and drawbacks of DCS versus one share/one vote structures, and more on the specific common-ground concern as to whether and how such structures are subjected to contingent reversal or “sunset”. This Article compares the relative advantages and disadvantages of time-, ownership- and transfer-centered models of DCS sunset provisions. It argues in favor of the transfer-centered model on the grounds that: (a) its specific event-based trigger renders it less arbitrary in application than the time-centered model, and protects against the possibility of founders being prevented prematurely from realizing their long-term strategic vision (as is a risk with the time-centered sunset model); (b) it avoids the moral hazard and other perverse controller incentives that are prone to ensue from time-centered sunsets; and (c) unlike both the time- and ownership-centered models (which are motivated primarily by agency cost concerns), the transfer-centered model is sensitive to the powerful non-financial incentives that controllers typically have to safeguard and promote firm value, even where their corporate control rights significantly outweigh their corresponding cash flow rights. Accordingly, it suggests that the SEC and principal U.S. exchanges should resist recent calls from influential investor-related bodies to mandate time-based sunsets. Instead, domestic policymakers should look overseas to Hong Kong and Singapore, whose respective listing authorities have recently introduced transfer-based sunset requirements for DCS issuers, in considering the most appropriate blueprint for any future regulatory initiatives in this regard

The Origin of the Magellanic Stream

SHORTENED ABSTRACT: We present numerical investigations designed to critically test models of the origin of the Magellanic Stream. The most developed model is the tidal model which fails to reproduce several of its characteristic properties. We suggest an alternative model for the origin of the Stream which can explain all of its observed features and dynamics, as well as provide a strong constraint on the distribution of gas within the halo of the Milky Way. We propose that the Stream consists of material which was ram-pressure stripped from the Magellanic System during its last passage through an extended ionized disk of the Galaxy. This collision took place some 500 million years ago at a galacto-centric distance of about 65 kpc, and swept $\sim 20$\% of the least bound HI into the Stream. The gas with the lowest column density lost the most orbital angular momentum, and is presently at the tip of the Stream, having fallen to a distance of $\sim 20$ kpc from the Milky Way attaining a negative velocity of 200 \kms. To prevent the stripped material from leading the Magellanic Clouds and attaining too large an infall velocity, we postulate the existence of an extended dilute halo of diffuse ionized gas surrounding the Milky Way. If the halo gas is at the virial temperature of the potential well of the Milky Way, its thermal emission would contribute $\sim$ 40\% of the observed diffuse background radiation in the 0.5-1.0 keV (M) band, consistent with recent ROSAT measurements as well as pulsar dispersion measures. Ram pressure strippingComment: 20 pages in TeX format. Please request hardcopy of plots, tables and text from B

From Minimization to Exploitation: Re-conceptualizing the Corporate Governance Problem

Over the past three decades, the topic of corporate governance has become an increasingly high profile aspect of social-scientific scholarship, both in the Anglo-Saxon world and continental Europe. To a significant extent, however, the conceptual boundaries of the corporate governance debate have been set narrowly in accordance with the logic and language of the dominant \u27agency\u27 paradigm of governance. According to agency theory, the central \u27problem\u27 of corporate governance is the question of how to minimize the (harmful) consequences of the separation of ownership and control within public companies first identified by Berle and Means (1932), by reference to competitive market pressures coupled with market-based incentive and disciplinary mechanisms. In this article, we present an alternative interpretation of the corporate governance \u27problem\u27 premised on the logic and language of institution rather than the market, which we argue is both more empirically relevant and conceptually defensible than the dominant agency paradigm. To this end, we rely on existing (US) corporate law doctrine in conjunction with recent developments in the economic theory of the firm. According to the proposed \u27institutional\u27 model of corporate governance, the central governance \u27problem\u27 is that of how to exploit, rather than minimize, the (beneficial) consequences of the separation of ownership and control, so as to engender the development of a more dynamic and sustainable system of governance than that emanating from the free interplay of (stock) market forces

Corporate Power in the Public Eye: Reassessing the Implications of Berle’s Public Consensus Theory

We analyze Berle’s overall corporate governance project in accordance with what we see as its four core sub-themes: (A) the limitations of external market forces as a constraint on managerial decision-making power; (B) the desirability of internal (corporate) over external (market) actors in allocating corporate capital; (C) civil society and the public consensus as a continuous informal check on managerial decision-making power; and (D) shareholder democracy (as opposed to shareholder primacy or shareholder wealth maximization) as a socially instrumental institution. We seek to debunk the popular misconception that Berle’s early work was a defense of the orthodox shareholder primacy paradigm of corporate governance. This prefaces our analysis where we set out and, in turn, examine each of the above four sub-themes of Berle’s overall thinking on corporate governance. A recurring theme in this part of our discussion is the over-simplicity of attempting to connect Berle’s thinking to the later agency costs paradigm of corporate governance, which we believe fails to reflect the normative and institutional richness of Berle’s overall social-scientific project. We build on these insights by assessing the effects of our reinterpretation of Berle’s work on contemporary corporate governance debates. We suggest here that Berle’s lifetime work on corporate governance, when considered in an integral and non-selective way, provides the basis for a realistic and dynamic understanding of the concept of shareholder democracy and its relationship with wider civil society processes of public and political opinion formation

Population Pharmacokinetic and Pharmacodynamic Analysis of Buprenorphine for the Treatment of Neonatal Abstinence Syndrome

Neonatal abstinence syndrome (NAS) is a condition affecting newborns exposed to an opioid in utero. Symptoms of NAS include excessive crying, poor feeding, and disordered autonomic control. Up to 2/3 of infants will require pharmacologic therapies to reach symptom control. Opioids including morphine and methadone are the current first-line treatments. Buprenorphine is being investigated as a treatment of NAS. The purpose of this analysis was to evaluate the pharmacokinetics (PK) and pharmacodynamics (PD) of BUP in infants with NAS. Poster presented at American Society for Clinical Pharmacology and Therapeutics (ASCPT) 2017 Annual Meeting, March 15-18, 2017 in Washington DC.https://jdc.jefferson.edu/petposters/1004/thumbnail.jp

Current Progress in Therapeutic Gene Editing for Monogenic Diseases

Programmable nucleases allow defined alterations in the genome with ease-of-use, efficiency, and specificity. Their availability has led to accurate and widespread genome engineering, with multiple applications in basic research, biotechnology, and therapy. With regard to human gene therapy, nuclease-based gene editing has facilitated development of a broad range of therapeutic strategies based on both nonhomologous end joining and homology-dependent repair. This review discusses current progress in nuclease-based therapeutic applications for a subset of inherited monogenic diseases including cystic fibrosis, Duchenne muscular dystrophy, diseases of the bone marrow, and hemophilia and highlights associated challenges and future prospects

URA*: Uncertainty-aware Path Planning using Image-based Aerial-to-Ground Traversability Estimation for Off-road Environments

A major challenge with off-road autonomous navigation is the lack of maps or road markings that can be used to plan a path for autonomous robots. Classical path planning methods mostly assume a perfectly known environment without accounting for the inherent perception and sensing uncertainty from detecting terrain and obstacles in off-road environments. Recent work in computer vision and deep neural networks has advanced the capability of terrain traversability segmentation from raw images; however, the feasibility of using these noisy segmentation maps for navigation and path planning has not been adequately explored. To address this problem, this research proposes an uncertainty-aware path planning method, URA* using aerial images for autonomous navigation in off-road environments. An ensemble convolutional neural network (CNN) model is first used to perform pixel-level traversability estimation from aerial images of the region of interest. The traversability predictions are represented as a grid of traversal probability values. An uncertainty-aware planner is then applied to compute the best path from a start point to a goal point given these noisy traversal probability estimates. The proposed planner also incorporates replanning techniques to allow rapid replanning during online robot operation. The proposed method is evaluated on the Massachusetts Road Dataset, the DeepGlobe dataset, as well as a dataset of aerial images from off-road proving grounds at Mississippi State University. Results show that the proposed image segmentation and planning methods outperform conventional planning algorithms in terms of the quality and feasibility of the initial path, as well as the quality of replanned paths