1,950 research outputs found

    Zero-field superfluid density in d-wave superconductor evaluated from the results of muon-spin-rotation experiments in the mixed state

    Full text link
    We report on measurements of the in-plane magnetic penetration \lambda_{ab} in the optimally doped cuprate superconductor (BiPb)_2(SrLa)_2CuO_6+\delta (OP Bi2201) by means of muon-spin rotation (\muSR). We show that in unconventional dd-wave superconductors (like OP Bi2201), \muSR experiments conducted in various magnetic fields allow to evaluate the zero-field magnetic penetration depth \lambda_0, which relates to the zero-field superfluid density in terms of \rho_s\propto\lambda_0^-2.Comment: 4 pages, 5 figure

    Bolla Bollana boulder beds:A Neoproterozoic trough mouth fan in South Australia?

    Get PDF
    The Bolla Bollana Formation is an exceptionally thick (ca 1500 m), rift-related sedimentary succession cropping out in the northern Flinders Ranges, South Australia, which was deposited during the Sturtian (mid Cryogenian) glaciation. Lithofacies analysis reveals three distinct facies associations which chart changing depositional styles on an ice-sourced subaqueous fan system. The diamictite facies association is dominant, and comprises both massive and stratified varieties with a range of clast compositions and textures, arranged into thick beds (1 to 20 m), representing stacked, ice-proximal glaciogenic debris-flow deposits. A channel belt facies association, most commonly consisting of normally graded conglomerates and sandstones, displays scour and fill structure of ca 10 m width and 1 to 3 m depth: these strata are interpreted as channelized turbidites. Rare mud-filled channels in this facies association bear glacially striated lonestones. Finally, a sheet heterolithics facies association contains a range of conglomerates through sandstones to silty shales arranged into clear, normally graded cycles from the lamina to bed scale. These record a variety of non-channelized turbidites, probably occupying distal and/or inter-channel locations on the subaqueous fan. Coarsening and thickening-up cycles, capped by dolomicrites or mudstones, are indicative of lobe build out and abandonment, potentially as a result of ice lobe advance and stagnation. Dropstones, recognized by downwarped and punctured laminae beneath pebbles to boulders in shale, or in delicate climbing ripple cross-laminated siltstones, are clearly indicative of ice rafting. The co-occurrence of ice-rafted debris and striated lonestones strongly supports a glaciogenic sediment source for the diamictites. Comparison to Pleistocene analogues enables an interpretation as a trough mouth fan, most probably deposited leeward of a palaeo-ice stream. Beyond emphasizing the highly dynamic nature of Sturtian ice sheets, these interpretations testify to the oldest trough mouth fan recorded to date.Daniel P. Le Heron, Marie E. Busfield, and Alan S. Collin

    Performance quarto da carne: sete minutos de relações eróticas imersivas

    Get PDF
    This article describes the practices of the Pleorama Collective, evidencing the research process that led us to construct the Immersive Atmospheres, which are integral sensorial performative experiences. This clipping will focus on the case of the performance Meat Room, which is our ‘investigation’ about the oneiric universe of sexuality. After analyzing in the text the foundations of the repression of free sexuality, the values of pornography, genitality, fetishes and paraphilias, the mo-tivations, the process and the expectations of the most scandalous dream of the Collective will be presented, as well as its anti-cultural and health perspective.Este artículo describe las prácticas del Colectivo Pleorama, del cual soy integrante, evidenciando el proceso de investigación que nos llevó a construir las Atmósferas inmersivas, las cuales son experiencias performáticas sensoriales integrales. Este artículo se enfocará en el caso de la performance Cuarto de carne, que es nuestra “investigación” sobre el universo onírico de la sexualidad. Después de analizar en el texto los fundamentos de la represión a la libre sexualidad, los valores de la pornografía, de la genitalidad, de los fetiches y de las parafilias, se presentarán las motivaciones, el proceso y las expectativas del sueño más escandaloso del Colectivo, así como su perspectiva contra-cultural y de salud.Este artigo descreve as práticas do Coletivo Pleorama, evidenciando o processo de pesquisa que nos levou a construir as Atmosferas Imersivas, que são experiências performativas sensoriais integrais. Este recorte se concentrará no caso da Performance Quarto da carne, que é a nossa “investigação” sobre o universo onírico da sexualidade. Depois de analisar no texto os fundamentos da repressão da sexualidade gratuita, serão apresentados os valores da pornografia, genitália, fetiches e parafilias, as motivações, o processo e as expectativas do sonho mais escandaloso do Coletivo, bem como a sua perspectiva anticultural e de saúde

    Eighteen Months of Meeple Like Us:An Exploration into the State of Board Game Accessibility

    Get PDF
    The study of game accessibility to date has largely focused on the topic of accessibility within a video game context. Largely underexplored in the academic and professional literature is accessibility in the domain of tabletop games, especially those that are classified as part of the 'hobbyist' market. An ongoing series of research annotations, published on the blog Meeple Like Us, has been aimed at addressing this lack of attention. In this paper, the authors report on the work of the Meeple Centred Design project which to date has examined 116 board games for the accessibility issues they manifest and the lessons that can be learned for designers in this space. While the project has not achieved significant coverage of even a fraction of the available library of hobbyist games, currently numbering approximately one hundred thousand, it has discussed the issues with many of the most critically success and popular of these titles. This paper reports on results to date, methodology of the analyses, limitations of the project, and the future plans for work in this interesting game accessibility context

    High flow conditions mediate damaging impacts of sub-lethal thermal stress on corals' endosymbiotic algae

    Get PDF
    The effects of thermal anomalies on tropical coral endosymbiosis can be mediated by a range of environmental factors, which in turn ultimately influence coral health and survival. One such factor is the water flow conditions over coral reefs and corals. Although the physiological benefits of living under high water flow are well known, there remains a lack of conclusive experimental evidence characterizing how flow mitigates thermal stress responses in corals. Here we use in situ measurements of flow in a variety of reef habitats to constrain the importance of flow speeds on the endosymbiosis of an important reef building species under different thermal regimes. Under high flow speeds (0.15 m s−1) and thermal stress, coral endosymbionts retained photosynthetic function and recovery capacity for longer compared to low flow conditions (0.03 m s−1). We hypothesize that this may be due to increased rates of mass transfer of key metabolites under higher flow, putatively allowing corals to maintain photosynthetic efficiency for longer. We also identified a positive interactive effect between high flow and a pre-stress, sub-lethal pulse in temperature. While higher flow may delay the onset of photosynthetic stress, it does not appear to confer long-term protection; sustained exposure to thermal stress (eDHW accumulation equivalent to 4.9°C weeks) eventually overwhelmed the coral meta-organism as evidenced by eventual declines in photo-physiological function and endosymbiont densities. Investigating flow patterns at the scale of metres within the context of these physiological impacts can reveal interesting avenues for coral reef management. This study increases our understanding of the effects of water flow on coral reef health in an era of climate change and highlights the potential to learn from existing beneficial bio-physical interactions for the effective preservation of coral reefs into the future

    Variation in growth rates of branching corals along Australia's Great Barrier Reef

    Get PDF
    Coral growth is an important component of reef health and resilience. However, few studies have investigated temporal and/or spatial variation in growth of branching corals, which are important contributors to the structure and function of reef habitats. This study assessed growth (linear extension, density, and calcification) of three branching coral species (Acropora muricata, Pocillopora damicornis and Isopora palifera) at three distinct locations (Lizard Island, Davies/Trunk Reef, and Heron Island) along Australia’s Great Barrier Reef (GBR). Annual growth rates of all species were highest at Lizard Island and declined with increasing latitude, corresponding with differences in temperature. Within locations, however, seasonal variation in growth did not directly correlate with temperature. Between October 2012 and October 2014, the highest growth of A. muricata was in the 2013–14 summer at Lizard Island, which was unusually cool and ~0.5 °C less than the long-term summer average temperature. At locations where temperatures reached or exceeded the long-term summer maxima, coral growth during summer periods was equal to, if not lower than, winter periods. This study shows that temperature has a significant influence on spatiotemporal patterns of branching coral growth, and high summer temperatures in the northern GBR may already be constraining coral growth and reef resilience

    Kinetic effects in stimulated Brillouin scattering

    No full text
    The role of ion and electron kinetic effects in the nonlinear evolution of stimulated Brillouin scattering (SBS) is investigated by means of particle-in-cell numerical simulations. The simulations were carried out in one and two spatial dimensions (1D and 2D), with a full PIC code, in which both ions and electrons are kinetic. The full PIC simulations are compared with those obtained from a hybrid PIC code (kinetic ions and Boltzmann electrons), making it possible to determine in which limit the electron kinetic effects are important. The simulation geometry corresponds to a coherent laser beam interacting with an expanding plasma slab. In the 1D simulations, the interaction becomes incoherent, as time goes on, in a domain that spatially begins in the plasma region close to the laser light entrance, and that ends within the plasma at a frontier which moves faster than the ion acoustic wave (IAW) velocity. The higher the laser intensity, the faster moves the frontier of this spatial domain. The SBS reflectivity drops at the very moment when this domain fills entirely the plasma. Two regimes have to be distinguished. In the regimes of low laser intensity, strong sub-harmonic generation of the excited IAW is observed to take place in this moving spatial domain, so that the SBS reflectivity drop is interpreted as being due to sub-harmonic generation. In the opposite regime of high laser intensity, there is no evidence of strong sub-harmonic generation, whereas a strong ion heating is observed, so that the reflectivity drop is interpreted as being due to enhanced ion damping. In the 1D simulations the electron kinetic effects are found to be able to smooth temporally the SBS reflectivity, although the overall picture remains the same when the electrons are taken as a Boltzmann fluid. In the 2D simulations, the SBS reflectivity is observed to drop rapidly in time because of the efficient nonlinear Landau damping on the ions, as previously reported by Cohen et al. [1]. In these 2D simulations, the electron kinetic effects are found to play a negligible role as compared with the ion kinetic effects
    corecore