13,521 research outputs found

    The art of being human : a project for general philosophy of science

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    Throughout the medieval and modern periods, in various sacred and secular guises, the unification of all forms of knowledge under the rubric of ‘science’ has been taken as the prerogative of humanity as a species. However, as our sense of species privilege has been called increasingly into question, so too has the very salience of ‘humanity’ and ‘science’ as general categories, let alone ones that might bear some essential relationship to each other. After showing how the ascendant Stanford School in the philosophy of science has contributed to this joint demystification of ‘humanity’ and ‘science’, I proceed on a more positive note to a conceptual framework for making sense of science as the art of being human. My understanding of ‘science’ is indebted to the red thread that runs from Christian theology through the Scientific Revolution and Enlightenment to the Humboldtian revival of the university as the site for the synthesis of knowledge as the culmination of self-development. Especially salient to this idea is science‘s epistemic capacity to manage modality (i.e. to determine the conditions under which possibilities can be actualised) and its political capacity to organize humanity into projects of universal concern. However, the challenge facing such an ideal in the twentyfirst century is that the predicate ‘human’ may be projected in three quite distinct ways, governed by what I call ‘ecological’, ‘biomedical’ and ‘cybernetic’ interests. Which one of these future humanities would claim today’s humans as proper ancestors and could these futures co-habit the same world thus become two important questions that general philosophy of science will need to address in the coming years

    Support of ASTP/KOSMOS fundulus embryo development experiment

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    Results from the Kosmos Biosatellite 782 flight are presented. Experiments with fish hatchlings are discussed along with postflight observation and testing. The preparation of fertilized eggs for the experiments is described

    Method and apparatus for minimizing multiple degree of freedom vibration transmission between two regions of a structure

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    Arrays of actuators are affixed to structural elements to impede the transmission of vibrational energy. A single pair is used to provide control of bending and extensional waves and two pairs are used to control torsional motion. The arrays are applied to a wide variety of structural elements such as a beam structure that is part of a larger framework that may or may not support a rigid or non-rigid skin. Electrical excitation is applied to the actuators that generate forces on the structure. These electrical inputs may be adjusted in their amplitude and phase by a controller in communication with appropriate vibrational wave sensors to impede the flow of vibrational power in all of the above mentioned wave forms beyond the actuator location. Additional sensor elements can be used to monitor the performance and adjust the electrical inputs to maximize the attenuation of vibrational energy

    Better definitions, better buildings?

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    Because of the magnitude of their impact on the environment, the way we design, build and operate our buildings must change. So-called &lsquo;sustainable&rsquo; buildings are now appearing in our cities. However, the term &lsquo;sustainable&rsquo; is now so widely used that it has lost all meaning. Other equally ill-defined descriptions are also being used of the new generation of buildings appearing in the built environment. These terms, including &lsquo;environmentally friendly&rsquo;, &lsquo;low energy&rsquo; and &lsquo;green&rsquo;. This paper argues that a lack of clarity over meaning can foster illusions, reflect careless thinking and/or provide cover for a business-as-usual agenda. In universities, courses for today&rsquo;s architecture and construction management students are being redesigned to include &lsquo;sustainability&rsquo;. However, a review of subject guides from Schools of Architecture in Australian universities indicates that &lsquo;sustainability&rsquo; is also being used misleadingly. While there is merit in both of the professional accreditation systems for buildings in Australia, there is certainly room for improvement. One scheme reinforces illusions by rewarding features that should merely be regarded as good building design. The &lsquo;sustainability&rsquo; objectives of the other scheme have narrowed significantly from the original intent. The authors conclude that the critical thinking of our students will be sharpened by defining sustainability correctly and that meaningless descriptors of buildings must be challenged.<br /

    Green roofs in Melbourne - potential and practice

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    In Melbourne, green roofs are increasingly being included in the new and retrofitted buildings that claim to be &lsquo;sustainable&rsquo; or &lsquo;green&rsquo;. This enthusiasm follows overseas experience where a variety of benefits have been recorded; these include a reduction in heating and cooling loads. This benefit is of particular importance because of the urgent need to reduce the greenhouse gas emissions associated with air conditioning. What is the potential for such savings and to what extent are some of the existing green roofs likely to achieve these benefits? This paper begins with a review of the overseas experience to reduce conditioning loads, particularly cooling, in temperate climates. Some observations on the potential and practice of green roofs in Melbourne is then presented. The results of measurements of plant canopy, soil and hard surface temperatures on two green roofs in the Melbourne Central Business District are discussed and future on-going work is outlined.<br /

    Neutrino Mass Hierarchy and Stepwise Spectral Swapping of Supernova Neutrino Flavors

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    We examine a phenomenon recently predicted by numerical simulations of supernova neutrino flavor evolution: the swapping of supernova νe\nu_e and νμ,τ\nu_{\mu,\tau} energy spectra below (above) energy \EC for the normal (inverted) neutrino mass hierarchy. We present the results of large-scale numerical calculations which show that in the normal neutrino mass hierarchy case, \EC decreases as the assumed νeνμ,τ\nu_e\rightleftharpoons\nu_{\mu,\tau} effective 2×22\times 2 vacuum mixing angle (θ13\simeq \theta_{1 3}) is decreased. However, these calculations also indicate that \EC is essentially independent of the vacuum mixing angle in the inverted neutrino mass hierarchy case. With a good neutrino signal from a future Galactic supernova, the above results could be used to determine the neutrino mass hierarchy even if θ13\theta_{13} is too small to be detected in terrestrial neutrino oscillation experiments.Comment: 4 pages, 2 figures. Version accepted by PR

    Flavor Evolution of the Neutronization Neutrino Burst from an O-Ne-Mg Core-Collapse Supernova

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    We present results of 3-neutrino flavor evolution simulations for the neutronization burst from an O-Ne-Mg core-collapse supernova. We find that nonlinear neutrino self-coupling engineers a single spectral feature of stepwise conversion in the inverted neutrino mass hierarchy case and in the normal mass hierarchy case, a superposition of two such features corresponding to the vacuum neutrino mass-squared differences associated with solar and atmospheric neutrino oscillations. These neutrino spectral features offer a unique potential probe of the conditions in the supernova environment and may allow us to distinguish between O-Ne-Mg and Fe core-collapse supernovae.Comment: 4 pages, 2 figures. Version accepted by PR

    Submillimeter observations of OH and CH in M42

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    The (sup 2) pi sub 1/2 (J = 3/2 to 1/2) transitions of OH at 163.12 and 163.40 micro m have been detected and upper limits have been obtained for the (sup 2) pi sub 3/2 (J = 3/2 to 1/2) transitions of CH at 149.09 and 149.39 micro m, in observations of the Kleinmann-Low Nebula of Orion. All four flux levels lie between 1 and 1.2 x 10 to the 17th power/sq.cm. The OH lines are bright when compared to the lower, (sup 2) pi sub 3/2 (J = 5/2 to 3/2) fluxes reported and imply that the 119 micro m emission observed is partially self-absorbed. The combined results provide strong constraints. Taken together with existing data on molecular hydrogen and CO and recent data on other OH transition, they suggest OH emission from post-shock regions at temperatures T approx 1000 k, densities approx. 7 x 10 to the 6th powr/cu cm N sub OH approx 80/cu cm optically thick for the (sup 2) pi sub 3/2 (J = 5/2 to 3/2), 119 micro m but only partially self-absorbing in the (J = 7/2 to 3/2), 84 micro m transitions over a Doppler velocity bandwidth of 30 km/sec. The OH column density is N sub OH approx 4 x 10 to the 16th powr/sq cm. in the emitting regions which occupy a fraction of approx 0.1 of a 1' x 1' field of view centered on the Becklin-Neugebauer source. The CO (J = 31 to 30), 84 micro m transition appears to lie sufficiently close to one of the 84 micro m OH line components to be partially absorbed as well, through a Bowen-type mechanism

    Coherent Development of Neutrino Flavor in the Supernova Environment

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    We calculate coherent neutrino and antineutrino flavor transformation in the supernova environment, for the first time including a self-consistent treatment of forward scattering-induced coupling and entanglement of intersecting neutrino/antineutrino trajectories. For the atmospheric neutrino mass-squared difference we find that in the normal (inverted) mass hierarchy the more tangentially-propagating (radially-propagating) neutrinos and antineutrinos can initiate collective, simultaneous medium-enhanced flavor conversion of these particles across broad ranges of energy and propagation direction. Accompanying alterations in neutrino/antineutrino energy spectra and/or fluxes could affect supernova nucleosynthesis and the expected neutrino signal.Comment: 4 pages, 3 figure
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