2,465 research outputs found

    Beyond the Principles of Bioethics: Facing the Consequences of Fundamental Moral Disagreement

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    Given intractable secular moral pluralism, the force and significance of the four principles (autonomy, beneficence, non-maleficence, and justice) of Tom Beauchamp and James Childress must be critically re-considered. This essay examines the history of the articulation of these four principles of bioethics, showing why initially there was an illusion of a common morality that led many to hold that the principles could give guidance across cultures. But there is no one sense of the content or the theoretical justification of these principles. In addition, a wide range of secular moral and bioethical choices has been demoralized into lifestyle choices; the force of the secular moral point of view has also been deflated, thus compounding moral pluralism. It is the political generation of the principles that provides a common morality in the sense of an established morality. The principles are best understood as embedded not in a common morality, sensu stricto, but in that morality that is established at law and public policy in a particular polity. Although moral pluralism is substantive and intractable at the level of moral content, in a particular polity a particular morality and a particular bioethics can be established, regarding which health care ethics consultants can be experts. Public morality and bioethics are at their roots a political reality

    Physicians and the Community of Physicians: An Account of Collective Responsibilities

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    Editor\u27s note: This paper was read at the eighth annual University of Dayton Philosophy Colloquium, held in 1979. In the course of this paper, I will first present a sketch of some of the cardinal characteristics of professions, as these characteristics bear upon understanding their collective responsibilities. After a brief review of these distinguishing characteristics, I will compare the different senses of obligations that one can attribute to professions and then to their members. I will first examine what is involved in simply being a member of a profession, then a member of a profession within a particular governmental organization (i.e., a state), and finally, the collective responsibility of members of particular professional associations. On the basis of these background reflections, I will proceed to address some particular issues concerning the collective responsibilities of physicians

    Summer Seminars for College Teachers (1975): Conference Proceeding 06

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    Radiative transfer modelling of parsec-scale dusty warped discs

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    Warped discs have been found on (sub-)parsec scale in some nearby Seyfert nuclei, identified by their maser emission. Using dust radiative transfer simulations we explore their observational signatures in the infrared in order to find out whether they can partly replace the molecular torus. Strong variations of the brightness distributions are found, depending on the orientation of the warp with respect to the line of sight. Whereas images at short wavelengths typically show a disc-like and a point source component, the warp itself only becomes visible at far-infrared wavelengths. A similar variety is visible in the shapes of the spectral energy distributions. Especially for close to edge-on views, the models show silicate feature strengths ranging from deep absorption to strong emission for variations of the lines of sight towards the warp. To test the applicability of our model, we use the case of the Circinus galaxy, where infrared interferometry has revealed a highly elongated emission component matching a warped maser disc in orientation and size. Our model is for the first time able to present a physical explanation for the observed dust morphology as coming from the AGN heated dust. As opposed to available torus models, a warped disc morphology produces a variety of silicate feature shapes for grazing lines of sight, close to an edge-on view. This could be an attractive alternative to a claimed change of the dust composition for the case of the nearby Seyfert 2 galaxy NGC 1068, which harbours a warped maser disc as well.Comment: accepted by MNRA

    Hybrid architecture active wavefront sensing and control system, and method

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    According to various embodiments, provided herein is an optical system and method that can be configured to perform image analysis. The optical system can comprise a telescope assembly and one or more hybrid instruments. The one or more hybrid instruments can be configured to receive image data from the telescope assembly and perform a fine guidance operation and a wavefront sensing operation, simultaneously, on the image data received from the telescope assembly

    Dust emission from a parsec-scale structure in the Seyfert 1 nucleus of NGC 4151

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    We report mid-IR interferometric measurements with \sim 10 mas resolution, which resolve the warm (T = 285 +25 / -50 K) thermal emission at the center of NGC 4151. Using pairs of VLT 8.2 m telescopes with MIDI and by comparing the data to a Gaussian model, we determined the diameter of the dust emission region, albeit only along one position angle, to be 2.0 +/- 0.4 pc (FWHM). This is the first size and temperature estimate for the nuclear warm dust distribution in a Seyfert 1 galaxy. The parameters found are comparable to those in Seyfert 2 galaxies, thus providing direct support for the unified model. Using simple analytic temperature distributions, we find that the mid-infrared emission is probably not the smooth continuation of the hot nuclear source that is marginally resolved with K band interferometry. We also detected weak excess emission around 10.5 micron in our shorter baseline observation, possibly indicating that silicate emission is extended to the parsec scale.Comment: 5 pages, 4 figures, accepted for publication in The Astrophysical Journal Letter

    Linear and nonlinear waveguides induced by optical vortex solitons

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    We study, numerically and analytically, linear and nonlinear waveguides induced by optical vortex solitons in a Kerr medium. Both fundamental and first-order guided modes are analyzed, as well as the cases of effectively defocusing and focusing nonlinearity.Comment: 3 pages, 3 figures, changed conten

    An analysis method for time ordered data processing of Dark Matter experiments

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    The analysis of the time ordered data of Dark Matter experiments is becoming more and more challenging with the increase of sensitivity in the ongoing and forthcoming projects. Combined with the well-known level of background events, this leads to a rather high level of pile-up in the data. Ionization, scintillation as well as bolometric signals present common features in their acquisition timeline: low frequency baselines, random gaussian noise, parasitic noise and signal characterized by well-defined peaks. In particular, in the case of long-lasting signals such as bolometric ones, the pile-up of events may lead to an inaccurate reconstruction of the physical signal (misidentification as well as fake events). We present a general method to detect and extract signals in noisy data with a high pile-up rate and qe show that events from few keV to hundreds of keV can be reconstructed in time ordered data presenting a high pile-up rate. This method is based on an iterative detection and fitting procedure combined with prior wavelet-based denoising of the data and baseline subtraction. {We have tested this method on simulated data of the MACHe3 prototype experiment and shown that the iterative fitting procedure allows us to recover the lowest energy events, of the order of a few keV, in the presence of background signals from a few to hundreds of keV. Finally we applied this method to the recent MACHe3 data to successfully measure the spectrum of conversion electrons from Co57 source and also the spectrum of the background cosmic muons

    VLTI/AMBER observations of the Seyfert nucleus of NGC 3783

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    Context. The putative tori surrounding the accretion disks of active galactic nuclei (AGNs) play a fundamental role in the unification scheme of AGNs. Infrared long-baseline interferometry allows us to study the inner dust distribution in AGNs with unprecedented spatial resolution over a wide infrared wavelength range. Aims. Near- and mid-infrared interferometry is used to investigate the milli-arcsecond-scale dust distribution in the type 1.5 Seyfert nucleus of NGC 3783. Methods. We observed NGC 3783 with the VLTI/AMBER instrument in the K-band and compared our observations with models. Results. From the K-band observations, we derive a ring-fit torus radius of 0.74 +/- 0.23 mas or 0.16 +/- 0.05 pc. We compare this size with infrared interferometric observations of other AGNs and UV/optical-infrared reverberation measurements. For the interpretation of our observations, we simultaneously model our near- and mid-infrared visibilities and the SED with a temperature/density-gradient model including an additional inner hot 1400 K ring component
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