EXIST's Gamma-Ray Burst Sensitivity

We use semi-analytic techniques to evaluate the burst sensitivity of designs for the EXIST hard X-ray survey mission. Applying these techniques to the mission design proposed for the Beyond Einstein program, we find that with its very large field-of-view and faint gamma-ray burst detection threshold, EXIST will detect and localize approximately two bursts per day, a large fraction of which may be at high redshift. We estimate that EXIST's maximum sensitivity will be ~4 times greater than that of Swift's Burst Alert Telescope. Bursts will be localized to better than 40 arcsec at threshold, with a burst position as good as a few arcsec for strong bursts. EXIST's combination of three different detector systems will provide spectra from 3 keV to more than 10 MeV. Thus, EXIST will enable a major leap in the understanding of bursts, their evolution, environment, and utility as cosmological probes.Comment: 25 pages, 10 figures, accepted by Ap

A Functional Naturalism

I provide two arguments against value-free naturalism. Both are based on considerations concerning biological teleology. Value-free naturalism is the thesis that both (1) everything is, at least in principle, under the purview of the sciences and (2) all scientific facts are purely non-evaluative. First, I advance a counterexample to any analysis on which natural selection is necessary to biological teleology. This should concern the value-free naturalist, since most value-free analyses of biological teleology appeal to natural selection. My counterexample is unique in that it is likely to actually occur. It concerns the creation of synthetic life. Recent developments in synthetic biology suggest scientists will eventually be able to develop synthetic life. Such life, however, would not have any of its traits naturally selected for. Second, I develop a simple argument that biological teleology is a scientific but value-laden notion. Consequently, value-free naturalism is false. I end with some concluding remarks on the implications for naturalism, the thesis that (1). Naturalism may be salvaged only if we reject (2). (2) is a dogma that unnecessarily constrains our conception of the sciences. Only a naturalism that recognizes value-laden notions as scientifically respectable can be true. Such a naturalism is a functional naturalism

Using the Active Collimator and Shield Assembly of an EXIST-Type Mission as a Gamma-Ray Burst Spectrometer

The Energetic X-ray Imaging Survey Telescope (EXIST) is a mission design concept that uses coded masks seen by Cadmium Zinc Telluride (CZT) detectors to register hard X-rays in the energy region from 10 keV to 600 keV. A partially active or fully active anti-coincidence shield/collimator with a total area of between 15 and 35 square meters will be used to define the field of view of the CZT detectors and to suppress the background of cosmic-ray-induced events. In this paper, we describe the use of a sodium activated cesium iodide shield/collimator to detect gamma-ray bursts (GRBs) and to measure their energy spectra in the energy range from 100 keV up to 10 MeV. We use the code GEANT4 to simulate the interactions of photons and cosmic rays with the spacecraft and instrument and the code DETECT2000 to simulate the optical properties of the scintillation detectors. The shield collimator achieves a nu-F-nu sensitivity of 3 x 10^(-9) erg cm^(-2) s^(-1) and 2 x 10^(-8) erg cm^(-2) s^(-1) at 100 keV and 600 keV, respectively. The sensitivity is well matched to that of the coded mask telescope. The broad energy coverage of an EXIST-type mission with active shields will constrain the peak of the spectral energy distribution (SED) for a large number of GRBs. The measurement of the SED peak may be key for determining photometric GRB redshifts and for using GRBs as cosmological probes.Comment: 20 pages, 10 Figures, Accepted May 19, 2006 A&

Integrating quality into the cycle of therapeutic development

The quality of healthcare, particularly as reflected in current practice versus the available evidence, has become a major focus of national health policy discussions. Key components needed to provide quality care include: 1) development of quality indicators and performance measures from specific practice guidelines, 2) better ways to disseminate such guidelines and measures, and 3) development of support tools to promote standardized practice. Although rational decision-making and development of practice guidelines have relied upon results of randomized trials and outcomes studies, not all questions can be answered by randomized trials, and many treatment decisions necessarily reflect physiology, intuition, and experience when treating individuals. Debate about the role of "evidence-based medicine" also has raised questions about the value of applying trial results in practice, and some skepticism has arisen about whether advocated measures of clinical effectiveness, the basic definition of quality, truly reflect a worthwhile approach to improving medical practice. We provide a perspective on this issue by describing a model that integrates quantitative measurements of quality and performance into the development cycle of existing and future therapeutics. Such a model would serve as a basic approach to cardiovascular medicine that is necessary, but not sufficient, to those wishing to provide the best care for their patients

A Unifying Theory of Biological Function

A new theory that naturalizes biological function is explained and compared with earlier etiological and causal role theories. Etiological theories explain functions from how they are caused over their evolutionary history. Causal role theories analyze how functional mechanisms serve the current capacities of their containing system. The new proposal unifies the key notions of both kinds of theories, but goes beyond them by explaining how functions in an organism can exist as factors with autonomous causal efficacy. The goal-directedness and normativity of functions exist in this strict sense as well. The theory depends on an internal physiological or neural process that mimics an organism’s fitness, and modulates the organism’s variability accordingly. The structure of the internal process can be subdivided into subprocesses that monitor specific functions in an organism. The theory matches well with each intuition on a previously published list of intuited ideas about biological functions, including intuitions that have posed difficulties for other theories

Preparing to work: dramaturgy, cynicism and normative ‘remote’ control in the socialization of graduate recruits in management consulting

online) This paper examines the socialization of graduate recruits into a knowledge intensive labour process and organizational culture. Theoretically the paper draws upon the idea of ‘preparing for work’ to position this early socialization as a crucial moment in the production of subjectivities suited (and booted) for the labour process of management consulting. Empirically the paper reports on a two-day induction session for new graduate recruits joining a global management consultancy and their responses to this training. Particular attention is given to the use of role-play and a dramaturgical workshop used in part of the training process. The paper argues that the utilization of dramaturgy in training is consistent with the overall approach to control developed in the firm in response to the fact that the labour process of consulting is often conducted on client sites, away from any direct supervisory gaze. As such, the consultants were subjected to a form of cultural control that was designed to function independently of direct supervision. This control did not operate directly upon the new employees professed values, however, but at one step removed so that a ‘cynical distance’ from the content of the organization’s culture was accepted so long as a professional ‘ethic of behaviour’ was established. By focusing on an ‘ethic of behaviour’ these young professionals were encouraged to internalize a self-control akin to that of an actor, rather than internalizing the corporate values entirely

Evaluation of an ethidium monoazide-enhanced 16S rDNA real-time polymerase chain reaction assay for bacterial screening of platelet concentrates and comparison with automated culture

Background Culture‐based systems are currently the preferred means for bacterial screening of platelet (PLT) concentrates. Alternative bacterial detection techniques based on nucleic acid amplification have also been developed but these have yet to be fully evaluated. In this study we evaluate a novel 16S rDNA polymerase chain reaction (PCR ) assay and compare its performance with automated culture. Study Design and Methods A total of 2050 time‐expired, 176 fresh, and 400 initial‐reactive PLT packs were tested by real‐time PCR using broadly reactive 16S primers and a “universal” probe (TaqMan , Invitrogen). PLTs were also tested using a microbial detection system (BacT /ALERT , bioMérieux) under aerobic and anaerobic conditions. Results Seven of 2050 (0.34%) time‐expired PLTs were found repeat reactive by PCR on the initial nucleic acid extract but none of these was confirmed positive on testing frozen second aliquots. BacT /ALERT testing also failed to confirm any time‐expired PLTs positive on repeat testing, although 0.24% were reactive on the first test. Three of the 400 “initial‐reactive” PLT packs were found by both PCR and BacT /ALERT to be contaminated (Escherichia coli , Listeria monocytogenes , and Streptococcus vestibularis identified) and 14 additional packs were confirmed positive by BacT /ALERT only. In 13 of these cases the contaminating organisms were identified as anaerobic skin or oral commensals and the remaining pack was contaminated with Streptococcus pneumoniae . Conclusion These results demonstrate that the 16S PCR assay is less sensitive than BacT /ALERT and inappropriate for early testing of concentrates. However, rapid PCR assays such as this may be suitable for a strategy of late or prerelease testing