9,419 research outputs found

    Curriculum Studies in the posthuman condition/posthuman curriculum (studies)

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    In this article we discuss the difference between curriculum studies (as a field of inquiry) in the posthuman condition and posthuman curriculum (studies). The posthuman condition is characterised by both posthumanism and post-anthropocentrism and relates respectively, to how we now define human given humans’ entanglement with new technologies, and the ethical response-ability of humans in intra-action with the more-than-human-world in a context of impending ecological disaster. In this article we shall argue that although Enlightenment humanism has been challenged philosophically/conceptually both in discourses on anti-humanism and posthumanism, humanist approaches to curriculum studies remain with us in the posthuman condition – the ghosts of Dewey, Tyler, Freire, etc., imbue much of curriculum work. However, the posthuman condition also produces posthuman thought that makes it possible to reimagine curriculum studies, that we shall call posthuman curriculum (studies). We shall review different approaches to curriculum studies in the posthuman condition, and then turn our attention to posthuman curriculum (studies). We argue that curriculum (as a vital concept) in posthumanist terms is intelligible and manifests through intra-actions, processes of becoming and experimenting. Set against sedentary states of being that mark curriculum studies in the posthuman condition; becoming, intra-acting and experimenting in posthuman curriculum (studies) are acts, doings in and of this world. The acts and doings in posthuman curriculum (studies) that are mostly written about include: improvisation, theorisation and diffraction. To these we add and specifically discuss quantum tunnelling, tracing, and desiring. Other forms of curriculum experimentation worthy of consideration in posthuman curriculum (studies) but not discussed in the article are queering, imagining, and writing. Towards the end we make the point that although some connections with the past (such as those that haunt curriculum discourses) can be threatening to life, connections of the thick now hold potential and radical openness for newness

    Foraging strategies of coexisting lacertid lizards in the arid Tankwa Karoo Basin of South Africa

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    The original publication is available at http://africanzoology.journals.ac.za/pubFour lacertid lizards, Pedioplanis laticeps, P. lineo-ocellata, Meroles knoxii and Nucras tessellata, occur sympatrically on the arid plains of the Tankwa Karoo Basin in South Africa. The aim of this study was to evaluate the significance of foraging strategy in resource partitioning among the four species, allowing them to co-occur in a structurally simple system with a limited number of potential niches. Previous workers already identified P. lineo-ocellata and M. knoxii as sit-and-wait foragers and N. tessellata as an active forager. We recorded data on three foraging variables: movements per minute, proportion of time spent moving, and proportion of attacks on prey whilst moving, for juveniles and adults of P. laticeps. By comparing the foraging data obtained for P. laticeps to those for other lacertid species, we were able to demonstrate that adult P. laticeps are ambush foragers.We also noted a significant ontogenetic shift in foraging behaviour in P. laticeps, and, due to a significantly higher frequency of short brief movements, we classified juveniles as mixed foragers. The sharing of an ambush foraging strategy by at least three of the four lacertid species co-occurring on the Tankwa plains, suggests considerable overlap along the trophic dimension of ecological space. This overlap presumably promotes occupation of separate microhabitats by the three ambush foragers in the Tankwa Karoo Basin.Publisher's versio

    Anaesthesia for transvenous transcatheter tricuspid valve-in-valve implantation

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    The authors report and discuss the anaesthetic management of a transvenous transcatheter tricuspid valve replacement. The conduct of anaesthesia, the challenges encountered and the specific risks associated with the procedure will be discussed. Percutaneous tricuspid valve replacement may be safely performed under general anaesthesia, provided that the procedure is understood and all possible eventualities considered. As the quality of percutaneous prostheses improves, and if longterm follow-up confirms this as a safe option, anaesthesiologists will be expected to provide perioperative care for a growing number of these cases.Keywords: transvenous, transcatheter, tricuspid prosthesis, valve-in-valve implantatio

    Theory of pixel lensing towards M31 I: the density contribution and mass of MACHOs

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    POINT-AGAPE is an Anglo-French collaboration which is employing the Isaac Newton Telescope (INT) to conduct a pixel-lensing survey towards M31. In this paper we investigate what we can learn from pixel-lensing observables about the MACHO mass and fractional contribution in M31 and the Galaxy for the case of spherically-symmetric near-isothermal haloes. We employ detailed pixel-lensing simulations which include many of the factors which affect the observables. For a maximum MACHO halo we predict an event rate in V of up to 100 per season for M31 and 40 per season for the Galaxy. However, the Einstein radius crossing time is generally not measurable and the observed full-width half-maximum duration provides only a weak tracer of lens mass. Nonetheless, we find that the near-far asymmetry in the spatial distribution of M31 MACHOs provides significant information on their mass and density contribution. We present a likelihood estimator for measuring the fractional contribution and mass of both M31 and Galaxy MACHOs which permits an unbiased determination to be made of MACHO parameters, even from data-sets strongly contaminated by variable stars. If M31 does not have a significant population of MACHOs in the mass range 0.001-1 Solar masses strong limits will result from the first season of INT observations. Simulations based on currently favoured density and mass values indicate that, after three seasons, the M31 MACHO parameters should be constrained to within a factor four uncertainty in halo fraction and an order of magnitude uncertainty in mass (90% confidence). Interesting constraints on Galaxy MACHOs may also be possible. For a campaign lasting ten years, comparable to the lifetime of current LMC surveys, reliable estimates of MACHO parameters in both galaxies should be possible. (Abridged)Comment: 21 pages, 14 figures. Submitted to MNRA

    AgapeZ1: a Large Amplification Microlensing Event or an Odd Variable Star Towards the Inner Bulge of M31

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    AgapeZ1 is the brightest and the shortest duration microlensing candidate event found in the Agape data. It occured only 42" from the center of M31. Our photometry shows that the half intensity duration of the event6 is 4.8 days and at maximum brightness we measure a stellar magnitude of R=18.0 with B-R=0.80 mag color. A search on HST archives produced a single resolved star within the projected event position error box. Its magnitude is R=22.Comment: 4 pages with 5 figure

    MODELING OF HYDROTHERMAL FLUID CIRCULATION AS A TOOL FOR VOLCANIC HAZARD ASSESSMENT

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    Monitoring of geophysical and geochemical observ¬ables at the surface plays a main role in the under¬standing of—and the hazard evaluation of— active volcanoes. Measurable changes in these parameters should occur when a volcano approches eruptive con¬ditions. Hydrothermal activity is commonly studied as an efficient carrier of signals from the magmatic system. As the magmatic system evolves, the amount, temperature, and composition of magmatic fluids that feed the hydrothermal system change, in turn affecting the parameters that are monitored at the surface. Modeling of hydrothermal circulation, as shown in the past, may cause measurable gravity changes and ground deformation. In this work, we extend our previous studies and increase the number of observable parameters to include gas temperature, the rate of diffuse degassing, the extent of the degassing area, and electrical conductivity. The possibility of nonmagmatic disturbance needs to be carefully addressed to ensure a proper estimate of volcanic hazard

    Supersymmetry of the Schrodinger and PP Wave Solutions in Einstein-Weyl Supergravities

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    We obtain the Schrodinger and general pp-wave solutions with or without the massive vector in Einstein-Weyl supergravity. The vector is an auxiliary field in the off-shell supermultiplet and it acquires a kinetic term in the Weyl-squared super invariant. We study the supersymmetry of these solutions and find that turning on the massive vector has a consequence of breaking all the supersymmetry. The Schrodinger and also the pp-wave solutions with the massive vector turned off on the other hand preserve 1/4 of the supersymmetry.Comment: 13 pages, no figur

    Critical and Non-Critical Einstein-Weyl Supergravity

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    We construct N=1 supersymmetrisations of some recently-proposed theories of critical gravity, conformal gravity, and extensions of critical gravity in four dimensions. The total action consists of the sum of three separately off-shell supersymmetric actions containing Einstein gravity, a cosmological term and the square of the Weyl tensor. For generic choices of the coefficients for these terms, the excitations of the resulting theory around an AdS_4 background describe massive spin-2 and massless spin-2 modes coming from the metric; massive spin-1 modes coming from a vector field in the theory; and massless and massive spin-3/2 modes (with two unequal masses) coming from the gravitino. These assemble into a massless and a massive N=1 spin-2 multiplet. In critical supergravity, the coefficients are tuned so that the spin-2 mode in the massive multiplet becomes massless. In the supersymmetrised extensions of critical gravity, the coefficients are chosen so that the massive modes lie in a "window" of lowest energies E_0 such that these ghostlike fields can be truncated by imposing appropriate boundary conditions at infinity, thus leaving just positive-norm massless supergravity modes.Comment: 29 page

    Using Heavy Quark Spin Symmetry in Semileptonic BcB_c Decays

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    The form factors parameterizing the B_c semileptonic matrix elements can be related to a few invariant functions if the decoupling of the spin of the heavy quarks in B_c and in the mesons produced in the semileptonic decays is exploited. We compute the form factors as overlap integral of the meson wave-functions obtained using a QCD relativistic potential model, and give predictions for semileptonic and non-leptonic B_c decay modes. We also discuss possible experimental tests of the heavy quark spin symmetry in B_c decays.Comment: RevTex, 22 pages, 2 figure
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