Custom, Contract, and Kidney Exchange

In this Essay, we examine a case in which the organizational and logistical demands of a novel form of organ exchange (the nonsimultaneous, extended, altruistic donor (NEAD) chain) do not map cleanly onto standard cultural schemas for either market or gift exchange, resulting in sociological ambiguity and legal uncertainty. In some ways, a NEAD chain resembles a form of generalized exchange, an ancient and widespread instance of the norm of reciprocity that can be thought of simply as the obligation to pay it forward rather than the obligation to reciprocate directly with the original giver. At the same time, a NEAD chain resembles a string of promises and commitments to deliver something in exchange for some valuable consideration—that is, a series of contracts. Neither of these salient social imaginaries of exchange—gift giving or formal contract—perfectly meets the practical demands of the NEAD system. As a result, neither contract nor generalized exchange drives the practice of NEAD chains. Rather, the majority of actual exchanges still resemble a simpler form of exchange: direct, simultaneous exchange between parties with no time delay or opportunity to back out. If NEAD chains are to reach their full promise for large-scale, nonsimultaneous organ transfer, legal uncertainties and sociological ambiguities must be finessed, both in the practices of the coordinating agencies and in the minds of NEAD-chain participants. This might happen either through the further elaboration of gift-like language and practices, or through a creative use of the cultural form and motivational vocabulary, but not necessarily the legal and institutional machinery, of contract

Organ Entrepreneurs

The supply of human organs for transplantation might seem an unlikely place to begin thinking about entrepreneurship. After all, there is no production market for human organs and, with the surprising exception of Iran, legal rules around the world make the sale of human organs for transplantation a criminal offense. Yet entrepreneurs have been present throughout the history of organ transplantation — a history of the active exploration, innovation, and management of a potentially very controversial exchange at the seemingly clear boundaries that separate giving from selling, life from death, and right from wrong. This article explores the role of entrepreneurial activity in the organ transplantation industry, with the goal of showing how the specific case helps us understand the more general phenomenon of innovation in the shadow of the law, and the role of reciprocity and gift exchange in that process. We begin with a more general point about the connection between structures of exchange and their social legitimacy, illustrating it with a familiar current case from the (conventionally entrepreneurial) world of the “sharing economy”. We then describe three innovations in the world of organ transplantation, discussing the legitimation problems faced by innovators in each case, and the strategies they have drawn on. First, Kidney Paired Donation (KPD), one of the first entrepreneurial attempts to bridge the gap between kidney supply and demand, allows patients with willing, but biologically incompatible donors, to “swap” with a similarly situated pair. Second, Non-simultaneous, Extended Altruistic Donor chains (or “NEAD” chains), removed the simultaneity constraint imposed by KPD, allowing more flexibility and a greater number of transplants, but also inserting the possibility of strategic behavior by donor-recipient pairs. Finally, we consider the most recent innovation, Advanced Donation, in which a donor donates a kidney before her paired recipient has been matched to a specific donor or scheduled for surgery, creating new challenges and risks

Repugnance Management and Transactions in the Body

Researchers have made progress in understanding the role of repugnance in transactions involving the human body. Yet, often, the focus remains on exchange between individuals and how they mentally cope (or not) with repugnance. But these exchanges also entail a “vertical” dimension in which organizational and state actors both directly manage repugnance and also limit the repugnance management tools available to the marketplace. Analyzing repugnance and its management as an organizational and regulatory problem, in addition to an individual one, suggests that a single, harmonized system of exchange in bodily goods is unlikely to emerge with the passage of time

Precession during merger 1: Strong polarization changes are observationally accessible features of strong-field gravity during binary black hole merger

The short gravitational wave signal from the merger of compact binaries encodes a surprising amount of information about the strong-field dynamics of merger into frequencies accessible to ground-based interferometers. In this paper we describe a previously-unknown "precession" of the peak emission direction with time, both before and after the merger, about the total angular momentum direction. We demonstrate the gravitational wave polarization encodes the orientation of this direction to the line of sight. We argue the effects of polarization can be estimated nonparametrically, directly from the gravitational wave signal as seen along one line of sight, as a slowly-varying feature on top of a rapidly-varying carrier. After merger, our results can be interpreted as a coherent excitation of quasinormal modes of different angular orders, a superposition which naturally "precesses" and modulates the line-of-sight amplitude. Recent analytic calculations have arrived at a similar geometric interpretation. We suspect the line-of-sight polarization content will be a convenient observable with which to define new high-precision tests of general relativity using gravitational waves. Additionally, as the nonlinear merger process seeds the initial coherent perturbation, we speculate the amplitude of this effect provides a new probe of the strong-field dynamics during merger. To demonstrate the ubiquity of the effects we describe, we summarize the post-merger evolution of 104 generic precessing binary mergers. Finally, we provide estimates for the detectable impacts of precession on the waveforms from high-mass sources. These expressions may identify new precessing binary parameters whose waveforms are dissimilar from the existing sample.Comment: 11 figures; v2 includes response to referee suggestion

Stress concentrations around voids in three dimensions : The roots of failure

Funding This work forms part of a NERC New Investigator award for DH (NE/I001743/1), which is gratefully acknowledged. Acknowledgments The authors would like to acknowledge the reviewers, Elizabeth Ritz and Phillip Resor. Their reviews were very constructive, both helping to improve the manuscripts consistency and highlighting a number of errors in the initial submission. The authors would also like to thank Lydia Jagger's keen eye and patience, she helped greatly in removing a number of grammatical errors from the initial draft.Peer reviewedPublisher PD

Pore geometry as a control on rock strength

This study was funded via RJW's University of Leicester start-up fund, as part of AAB's PhD project. We thank Don Swanson and Mike Poland at HVO, Hawai'i, for their help and advice during fieldwork planning and sample collection in the Koa'e fault system, and the National Park Service for granting a research permit to collect rock samples. Sergio Vinciguerra is thanked for access to the Rock Mechanics and Physics lab at the British Geological Survey and Audrey Ougier-Simonin is thanked for her help preparing samples and advice during testing. We thank Mike Heap (EOST Strasbourg) and an anonymous reviewer for their detailed and careful comments that greatly improved the manuscript.Peer reviewedPostprin

Intrinsic selection biases of ground-based gravitational wave searches for high-mass BH-BH mergers

The next generation of ground-based gravitational wave detectors may detect a few mergers of comparable-mass M\simeq 100-1000 Msun ("intermediate-mass'', or IMBH) spinning black holes. Black hole spin is known to have a significant impact on the orbit, merger signal, and post-merger ringdown of any binary with non-negligible spin. In particular, the detection volume for spinning binaries depends significantly on the component black hole spins. We provide a fit to the single-detector and isotropic-network detection volume versus (total) mass and arbitrary spin for equal-mass binaries. Our analysis assumes matched filtering to all significant available waveform power (up to l=6 available for fitting, but only l<= 4 significant) estimated by an array of 64 numerical simulations with component spins as large as S_{1,2}/M^2 <= 0.8. We provide a spin-dependent estimate of our uncertainty, up to S_{1,2}/M^2 <= 1. For the initial (advanced) LIGO detector, our fits are reliable for $M\in[100,500]M_\odot$ ($M\in[100,1600]M_\odot$). In the online version of this article, we also provide fits assuming incomplete information, such as the neglect of higher-order harmonics. We briefly discuss how a strong selection bias towards aligned spins influences the interpretation of future gravitational wave detections of IMBH-IMBH mergers.Comment: 18 pages, 15 figures, accepted by PRD. v2 is version accepted for publication, including minor changes in response to referee feedback and updated citation

The face of animal cognition

As an increasing number of researchers investigate the cognitive abilities of an ever‐wider range of animals, animal cognition is currently among the most exciting fields within animal behavior. Tinbergen would be proud: all four of his approaches are being pursued and we are learning much about how animals collect information and how they use that information to make decisions for their current and future states as well as what animals do not perceive or choose to ignore. Here I provide an overview of this productivity, alighting only briefly on any single example, to showcase the diversity of species, of approaches and the sheer mass of research effort currently under way. We are getting closer to understanding the minds of other animals and the evolution of cognition at an increasingly rapid rate.PostprintPeer reviewe