494 research outputs found

    A new hydraulic model of the left ventricle for the assessment of wall deformation

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    In-vitro modelling of the left heart

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    New students, new learning, new environments in higher education : literacies in the digital age

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    Information literacy is developing new meanings and importance in the online age of teaching and learning in higher education. Information literacy, as a highly prized graduate attribute, is related to the development of lifelong learning capacities. Its strong re-emergence in the form of digital literacy in the context of major online developments at Deakin University is considered through four cases. In each case the reader is asked to consider how the teaching staff members have conceived critical discipline-based information and digital literacies, how these conceptions are related to desired learning outcomes, the types of digital and online environments designed to support the development of these literacies, and how each one contributes to the development of lifelong learning capacities. Information and digital literacy is enlivened through being situated in broader understandings of new generations of learners, new forms of learning and new e-supported learning environments. Educational design, evaluation, research and technology implications of these new types of digital and online-based teaching and learning environments are finally examined.<br /

    In Vitro Flow Modelling for Mitral Valve Leakage Quantification

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    In this study particle image velocimetry (PIV) is used to measure and visualise the blood flow through a leaking mitral heart valve. The results are compared with the results from Doppler echocardiography and computational fluid dynamics (CFD). Using CAD, five-axis milling and Rapid Prototyping Machining (RPM) technology, a hydraulic in vitro flow model was developed and constructed which is compatible with flow investigation with 2D normal speed PIV and 2D Doppler echocardiography. The same CAD model was used to conduct the CFD analysis. PIV results compared successfully with Doppler echo and CFD results, both in the upstream converging region and downstream the turbulent regurgitated jet zone. These results are expected to improve the assessment of mitral valve regurgitation severity with Doppler echocardiography in clinical practice

    Demographic and Phenotypic Effects of Human Mediated Trophic Subsidy on a Large Australian Lizard (Varanus varius): Meal Ticket or Last Supper?

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    Humans are increasingly subsidizing and altering natural food webs via changes to nutrient cycling and productivity. Where human trophic subsidies are concentrated and persistent within natural environments, their consumption could have complex consequences for wild animals through altering habitat preferences, phenotypes and fitness attributes that influence population dynamics. Human trophic subsidies conceptually create both costs and benefits for animals that receive increased calorific and altered nutritional inputs. Here, we evaluated the effects of a common terrestrial human trophic subsidies, human food refuse, on population and phenotypic (comprising morphological and physiological health indices) parameters of a large predatory lizard (∼2 m length), the lace monitor (Varanus varius), in southern Australia by comparison with individuals not receiving human trophic subsidies. At human trophic subsidies sites, lizards were significantly more abundant and their sex ratio highly male biased compared to control sites in natural forest. Human trophic subsidies recipient lizards were significantly longer, heavier and in much greater body condition. Blood parasites were significantly lower in human trophic subsidies lizards. Collectively, our results imply that human trophic subsidized sites were especially attractive to adult male lace monitors and had large phenotypic effects. However, we cannot rule out that the male-biased aggregations of large monitors at human trophic subsidized sites could lead to reductions in reproductive fitness, through mate competition and offspring survival, and through greater exposure of eggs and juveniles to predation. These possibilities could have negative population consequences. Aggregations of these large predators may also have flow on effects to surrounding food web dynamics through elevated predation levels. Given that flux of energy and nutrients into food webs is central to the regulation of populations and their communities, we advocate further studies of human trophic subsidies be undertaken to evaluate the potentially large ecological implications of this significant human environmental alteration

    Erhöhung der Sprachqualität von CASA separierten Sprachsignalen

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    Ziel dieser Arbeit war es unter Einsatz einer Auswahl an Algorithmen die Sprachqualität von CASA separierten Sprachsignalen zu verbessern. Der Ursprung dieses Problems liegt in der von CASA verwendeten Zeit-Frequenz-Maskierung. Diese kann zu einer fehlerbehafteten Ausgabe führen, wenn zur gleichen Zeit zwei Sprecher den selben Frequenzbereich mit ihren Stimmen abdecken. Der beschriebene Bereich kann folglich nur als Ganzes einem Sprecher zugeordnet werden, sodass fehlerbehaftete Signale entstehen. Zur Verbesserung dieser wurde der Einsatz eines LPC-Vocoders, die Reduktion der Abtastrate der Signale sowie eine Kombination beider als Reparaturverfahren eingesetzt und überprüft

    The biogeographical history of the interaction between mycoheterotrophic Thismia (Thismiaceae) plants and mycorrhizal Rhizophagus (Glomeraceae) fungi

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    Aim Achlorophyllous mycoheterotrophic plants and mycorrhizal fungi often have highly specific interactions that potentially limit the plants’ distribution and diversification potential. However, specificity in biotic interactions may differ considerably over a species’ distribution range and therefore interactions need to be studied over their entire range to assess their evolution in space and time. The present study investigates the biogeographical history of the interaction between five closely related mycoheterotrophic Thismia species and arbuscular mycorrhizal fungi over the distribution range of the plant species. Location Temperate south-east Australia and New Zealand. Methods Phylogenetic relationships of Thismia (nrITS and mtcob) and their arbuscular mycorrhizal fungi (partial nrSSU) were reconstructed based on data from 65 plant specimens. The diversification times in Thismia were estimated with a Bayesian relaxed clock approach using a Dioscoreales framework (nrSSU, mtatp1, mtmatR, mtnad1 b-c). Ancestral geographical ranges were reconstructed using a maximum likelihood approach. The same approach was used to reconstruct ancestral mycorrhizal associations. Results Our analysis shows that Thismia plants have highly specific, phylogenetically conserved and evolutionarily persistent interactions with Rhizophagus fungi. Nevertheless, Thismia was able to diversify and radiate recently due to the wide geographical distribution of the host fungi. In addition, we find that although the mycorrhizal interactions of this clade of mycoheterotrophs are strictly bound to a fungal lineage, host switches remain possible. Main conclusions In this clade of closely related mycoheterotrophs, dependency on highly specific fungal interactions is the result of phylogenetic niche conservatism, acting over at least 12 million years. Nevertheless, plants that are dependent on highly specific fungal interactions have ample opportunities to disperse and radiate over the geographical range of their hosts. Our study highlights the need to link the ecology and evolution of species interactions over broad geographical and evolutionary scales for understanding mycorrhizal interactions
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