44 research outputs found

    Empirical Comparisons of Virtual Environment Displays

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    There are many different visual display devices used in virtual environment (VE) systems. These displays vary along many dimensions, such as resolution, field of view, level of immersion, quality of stereo, and so on. In general, no guidelines exist to choose an appropriate display for a particular VE application. Our goal in this work is to develop such guidelines on the basis of empirical results. We present two initial experiments comparing head-mounted displays with a workbench display and a foursided spatially immersive display. The results indicate that the physical characteristics of the displays, users' prior experiences, and even the order in which the displays are presented can have significant effects on performance

    A rare case of a giant epidermal cyst over the back

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    Epidermoid cysts are commonly called as sebaceous cysts that mostly occur in the subcutaneous plain. Giant epidermoid cysts are rare and generally greater than 5 cm in size. Few cases of malignant transformation of the sebaceous cysts have also been reported in literature

    Resilient and affordable housing for all: Lessons on house building from Kochi and Trivandrum, India

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    This paper analyses lessons from Kochi and Trivandrum, Kerala, India, where municipal government and community partnerships on house building projects have led to better quality new housing stock while reducing costs and environmental impacts. It finds that by placing participation at the heart of their processes, these cities have achieved 100 per cent occupancy rates at a lower cost, while also cutting carbon emissions and providing economic benefits. Nationwide, costs and occupancy levels of Kochi and Trivandrum could save Rs. 118 billion (US$1.71 billion), or build an additional 816,000 homes

    Evaluating hydraulic fracture geometry from sonic anisotropy and radioactive tracer logs

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    In developing a new field or reservoir, many parameters are important in understanding the success or possible areas for improvement in hydraulic fracturing. Estimating fracture geometry is essential to effectively calibrate a reservoir model to production results. Radioactive (RA) tracers have been used in hydraulic fracturing treatments to infer fracture dimensions. Three stable isotopes (i.e. Scandium, Iridium and Antimony) were used in various parts of the treatment to understand the progression of hydraulic fracture growth. Advanced sonic anisotropy logging tools, using a broader range of frequency acquisition, were used to enable shear measurement in cased hole environments over a wide range of interbedded coal, shale and sandstone sequences both before and after the hydraulic fracture treatment. Amplitude and anisotropy changes after a hydraulic fracture have been measured using sonic anisotropy logging and used to infer fracture height. Finally, the sonic anisotropy can be evaluated above and below the perforated interval and investigate hydraulic fracture height growth away from the wellbore, potentially visualising a greater distance than available with RA tracers. We will show how sonic anisotropy and radioactive tracer logging methods can be used to better understand the fracture geometry and aid further design work. The paper will present data from two (2) wells in the Walloon Coal Measures of the Surat Basin where both RA tracers and sonic anisotropy logs were used to infer fracture dimensions. Both wells used a combination of treated water stages, containing low concentrations of proppant, followed by borate-crosslinked gelled water stages with higher concentrations of proppant. This project contained a large amount of other hydraulic fracturing diagnostics including treatment pressure history-matching, microseismic monitoring and surface tiltmeters. In this paper we will note how those diagnostics compared with the results presented herein, but their results are discussed in greater detail elsewhere (Johnson et al. 2010a). Generally, the results indicate good agreement between these two fracture diagnostic methods and the authors will illustrate the complimentary nature of these diagnostics in gaining a fuller understanding of fracture height, especially in environments of complex fracture development

    The role of cognitive and metacognitive factors in non-clinical paranoia and negative affect

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    Outcome of host-pathogen encounter is determined by the complex interplay between protective bacterial and host defense strategies. This complexity further amplifies with the existence of cell-to-cell phenotypic heterogeneity in pathogens which remains largely unexplored. In this study, we illustrated that heterogeneous expression of pneumolysin (Ply), a pore-forming toxin of the meningeal pathogen, S. pneumoniae (SPN) gives rise to stochastically different bacterial subpopulations with variable fate during passage across blood-brain barrier (BBB). We demonstrate that Ply mediated damage to pneumococcus containing vacuolar (PCV) membrane leads to recruitment of cytosolic "eat-me" signals, galectin-8 and ubiquitin, targeting SPN for autophagic clearance. However, a majority of high Ply producing subset extensively damages autophagosomes leading to pneumococcal escape into cytosol and efficient clearance by host ubiquitination machinery. Interestingly, a low Ply producing subset halts autophagosomal maturation and evades all intracellular defense mechanisms, promoting its prolonged survival and successful transcytosis across BBB, both in vitro and in vivo. Ply therefore acts as both, sword and shield implying that its smart regulation ensures optimal disease manifestation. Our elucidation of heterogeneity in Ply expression leading to disparate infection outcomes attempts to resolve the dubious role of Ply in pneumococcal pathogenesis
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