466 research outputs found

    Francisco de Vitoria on the Right to Free Trade and Justice

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    In 1538–39 Francisco de Vitoria delivered two relections: De Indis and De iure belli. This article distills from these writings the topic of free trade as a “human right” in accordance with ius gentium or the “law of peoples.” The right to free trade is rooted in a more fundamental right to communication and association. The rights to travel, to dwell, and to migrate precede the right to trade, which is also closely connected to the rights to preach, to protect converts, and to constitute Christian princes. This has significant repercussions on the field of business ethics: the right to free trade is ultimately founded directly on natural law and indirectly on divine law; trade is not independent of ethics; and trade is presented as an opportunity to develop the virtues of justice and friendship, among other repercussions. Vitoria is portrayed as a defender of private initiative and free markets

    A neo-aristotelian perspective on the need for artificial moral agents (AMAs)

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    We examine Van Wynsberghe and Robbins (JAMA 25:719-735, 2019) critique of the need for Artifcial Moral Agents (AMAs) and its rebuttal by Formosa and Ryan (JAMA 10.1007/s00146-020-01089-6, 2020) set against a neo-Aristotelian ethical background. Neither Van Wynsberghe and Robbins (JAMA 25:719-735, 2019) essay nor Formosa and Ryan’s (JAMA 10.1007/s00146-020-01089-6, 2020) is explicitly framed within the teachings of a specifc ethical school. The former appeals to the lack of “both empirical and intuitive support” (Van Wynsberghe and Robbins 2019, p. 721) for AMAs, and the latter opts for “argumentative breadth over depth”, meaning to provide “the essential groundwork for making an all things considered judgment regarding the moral case for building AMAs” (Formosa and Ryan 2019, pp. 1–2). Although this strategy may beneft their acceptability, it may also detract from their ethical rootedness, coherence, and persuasiveness, characteristics often associated with consolidated ethical traditions. Neo-Aristotelian ethics, backed by a distinctive philosophical anthropology and worldview, is summoned to fll this gap as a standard to test these two opposing claims. It provides a substantive account of moral agency through the theory of voluntary action; it explains how voluntary action is tied to intelligent and autonomous human life; and it distinguishes machine operations from voluntary actions through the categories of poiesis and praxis respectively. This standpoint reveals that while Van Wynsberghe and Robbins may be right in rejecting the need for AMAs, there are deeper, more fundamental reasons. In addition, despite disagreeing with Formosa and Ryan’s defense of AMAs, their call for a more nuanced and context-dependent approach, similar to neo-Aristotelian practical wisdom, becomes expedient

    Path and trajectory planning of a tethered UAV-UGV marsupial robotics system

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    This paper addresses the problem of trajectory planning in a marsupial robotic system consisting of an unmanned aerial vehicle (UAV) linked to an unmanned ground vehicle (UGV) through a non-taut tether that has a controllable length. The objective is to determine a synchronized collision-free trajectory for the three marsupial system agents: UAV, UGV, and tether. First, we present a path planning solution based on optimal Rapidly exploring Random Trees (RRT*) that takes into account constraints related to the positions of UAV, UGV, tether and the 3D environment. The specialization of the main RRT* methods allows us to obtain feasible solutions in short times. Then, the paper presents a trajectory planner based on non-linear least squares. The optimizer takes into account aspects not considered in the path planning, like temporal constraints of the motion that impose limits on the velocities and accelerations of the robots. Results from simulated scenarios demonstrate that the approach is able to generate obstacle-free and smooth trajectories for the UAV, UGV, and tether.Comment: 8 pages, 4 figures, 2 table

    Scalability of GHZ and random-state entanglement in the presence of decoherence

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    We derive analytical upper bounds for the entanglement of generalized Greenberger-Horne-Zeilinger states coupled to locally depolarizing and dephasing environments, and for local thermal baths of arbitrary temperature. These bounds apply for any convex quantifier of entanglement, and exponential entanglement decay with the number of constituent particles is found. The bounds are tight for depolarizing and dephasing channels. We also show that randomly generated initial states tend to violate these bounds, and that this discrepancy grows with the number of particles.Comment: 9 pages, 3 figure

    One-dimensional thermal pressure-driven expansion of a pair cloud into an electron-proton plasma

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    Recently a filamentation instability was observed when a laser-generated pair cloud interacted with an ambient plasma. The magnetic field it drove was strong enough to magnetize and accelerate the ambient electrons. It is of interest to determine if and how pair cloud-driven instabilities can accelerate ions in the laboratory or in astrophysical plasma. For this purpose, the expansion of a localized pair cloud with the temperature 400 keV into a cooler ambient electron-proton plasma is studied by means of one-dimensional particle-in-cell (PIC) simulations. The cloud's expansion triggers the formation of electron phase space holes that accelerate some protons to MeV energies. Forthcoming lasers might provide the energy needed to create a cloud that can accelerate protons.Comment: 5 pages 4 figures, accepted for publication in Physics of Plasma

    Climate fluctuations during the Holocene in NW Iberia: high and low latitude linkages

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    International audienceHigh resolution benthic foraminiferal oxygen and carbon stable isotopes (?18O, ?13C) from core EUGC-3B are used here to infer rapid climatic changes for the last 8500 yr in the RĂ­a de Muros (NW Iberian Margin). Benthic foraminiferal ?18O and ?13C potentially register migrations in the position of the hydrographic front formed between two different intermediate water masses: Eastern North Atlantic Central Water of subpolar origin (ENACWsp), and subtropical origin (ENACWsp). The isotopic records have been compared with two well established North Atlantic marine Holocene paleoceanographic records from low (Sea Surface Temperatures anomalies off Cape Blanc, NW Africa) and high latitudes (Hematite Stained Grains percentage, subpolar North Atlantic). This comparison clearly demonstrates that there is a strong link between high- and low-latitude climatic perturbations at centennial-millennial time scales during the Holocene. Spectral analyses also points at a pole-to-equator propagation of the so-called 1500 yr cycles. Our results demonstrate that during the Holocene, the NW Iberian Margin has undergone a series of cold episodes which are likely triggered at high latitudes in the North Atlantic and are rapidly propagated towards lower latitudes. Conceivably, the propagation of these rapid climatic changes involves a shift of atmospheric and oceanic circulatory systems and so a migration of the hydrographical fronts and water masses all along the North Atlantic area

    Molecular gas observations of the reddened quasar 3C 318

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    3C 318 is a z=1.574 radio-loud quasar. The small physical size of its radio jets indicate that these jets were triggered relatively recently. In addition to the ultraviolet continuum emission being reddened by dust, detections with IRAS and SCUBA show it to have an exceptionally high far-infrared luminosity. We present CO(2-1) observations of 3C 318 made with the IRAM Plateau de Bure Interferometer. We detect CO(2-1) emission with a FWHM=200 km/s at a signal-to-noise ratio of 5.4. There is evidence for positional (~ 20 kpc) and velocity (~ -400 km/s) offsets between the molecular gas and the quasar which may be due to the quasar experiencing a major merger. The mass of molecular gas inferred from our observations is M_{H_2}=(3.0 +/- 0.6) x 10^{10} M_sun. This molecular gas mass is comparable to that in sub-mm-selected galaxies at similar redshifts. The large molecular gas mass is consistent with the primary source of heating for the cool dust in this quasar to be massive star formation with a star formation rate of 1700 M_sun/yr and a gas depletion timescale of 20 Myr. Our observations support the idea that star formation episodes and jet triggering can be synchronised.Comment: 4 pages, 3 b/w figures, AJ, in pres

    Mechanical and tribological behavior of Ti/TiN and TiAl/TiAlN coated austempered ductile iron

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    Bilayer Ti/TiN and TiAl/TiAlN coatings were deposited onto austempered ductile iron (ADI) substrates by cathodic arc deposition in an industrial device. Structure and mechanical properties of the coated samples were comparatively examined. Wear behavior of the coated samples was investigated in comparison with uncoated ADI by means of rolling contact fatigue (RCF) tests, performed in a flat washer type testing rig and using lubricated pure rolling conditions. RCF tests results were analyzed using the two-parameter Weibull distribution and the Weibayes method. The results indicate that TiN and TiAlN coatings grew with a cubic-NaCl type structure. The arithmetic average roughness of the coated samples is similar for both coating variants. The surface hardness and residual stresses are higher for the TiAl/TiAlN coated samples. The coating hardness and elastic modulus are also higher for TiAl/TIAlN. The critical loads at massive delamination and the evolution of the friction coefficients are quite similar for both coating variants. Regarding RCF, failures in coated samples were characterized by substrate spalling. No massive delamination was observed in Ti/TiN and TiAl/TiAlN coatings. The statistical analysis indicates that the deposition of Ti/TiN improves noticeably the RCF resistance of ADI while the deposition of TiAl/TiAlN does not produce significant changes. The properties mismatch between substrate and coating seems to play an important role in the RCF behavior of coated samples, since Ti/TiN coatings possess a lower mismatch with respect to ADI substrates as compared to TiAl/TiAlN.Fil: Colombo, Diego Alejandro. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y TecnologĂ­a de Materiales. Universidad Nacional de Mar del Plata. Facultad de IngenierĂ­a. Instituto de Investigaciones en Ciencia y TecnologĂ­a de Materiales; ArgentinaFil: Mandri, Alejo Daniel. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: EcheverrĂ­a, MarĂ­a D.. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; ArgentinaFil: Massone, Juan Miguel. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y TecnologĂ­a de Materiales. Universidad Nacional de Mar del Plata. Facultad de IngenierĂ­a. Instituto de Investigaciones en Ciencia y TecnologĂ­a de Materiales; ArgentinaFil: Dommarco, Ricardo. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y TecnologĂ­a de Materiales. Universidad Nacional de Mar del Plata. Facultad de IngenierĂ­a. Instituto de Investigaciones en Ciencia y TecnologĂ­a de Materiales; Argentin

    Peptide Mass Spectra from Micrometer-Thick Ice Films Produced with Femtosecond Pulses

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    We present a cryogenic mass spectrometry protocol with the capability to detect peptides in the attomole dilution range from ice films. Our approach employs femtosecond laser pulses and implements neither substrate modification nor proton donor agents in the aqueous solution, known to facilitate analyte detection in mass spectrometry. In a systematic study, we investigated the impact of temperature, substrate composition, and irradiation wavelength (513 and 1026 nm) on the bradykinin signal onset. Our findings show that substrate choice and irradiation wavelength have a minor impact on signal intensity once the preparation protocol is optimized. However, if the temperature is increased from −140 to 0 °C, which is accompanied by ice film thinning, a somehow complex picture of analyte desorption and ionization is recognizable, which has not been described in the literature yet. Under cryogenic conditions (−140 °C), obtaining a signal is only possible from isolated sweet spots across the film. If the thin ice film is between −100 and −70 °C of temperature, these sweet spots appear more frequently. Ice sublimation triggered by temperatures above −70 °C leads to an intense and robust signal onset that could be maintained for several hours. In addition to the above findings, we notice that a vibrant fragmentation pattern produced is strikingly similar with both wavelengths. Our findings suggest that while following an optimized protocol, femtosecond mass spectrometry has excellent potential to analyze small organic molecules and peptides with a mass range of up to 2.5 kDa in aqueous solution without any matrix, as employed in matrix-assisted laser desorption/ionization (MALDI) or any substrate surface modification, found in surface-assisted laser desorption/ionization (SALDI)
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