1,538 research outputs found

    The role of bacterial secretion systems in the virulence of Gram-negative airway pathogens associated with cystic fibrosis

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    Cystic fibrosis (CF) is the most common lethal inherited disorder in Caucasians. It is caused by mutation of the CF transmembrane conductance regulator (CFTR) gene. A defect in the CFTR ion channel causes a dramatic change in the composition of the airway surface fluid, leading to a highly viscous mucus layer. In healthy individuals, the majority of bacteria trapped in the mucus layer are removed and destroyed by mucociliary clearance. However, in the lungs of patients with CF, the mucociliary clearance is impaired due to dehydration of the airway surface fluid. As a consequence, patients with CF are highly susceptible to chronic or intermittent pulmonary infections, often causing extensive lung inflammation and damage, accompanied by a decreased life expectancy. This mini review will focus on the different secretion mechanisms used by the major bacterial CF pathogens to release virulence factors, their role in resistance and discusses the potential for therapeutically targeting secretion systems

    Point triangulation through polyhedron collapse using the l∞ norm

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    Multi-camera triangulation of feature points based on a minimisation of the overall l(2) reprojection error can get stuck in suboptimal local minima or require slow global optimisation. For this reason, researchers have proposed optimising the l(infinity) norm of the l(2) single view reprojection errors, which avoids the problem of local minima entirely. In this paper we present a novel method for l(infinity) triangulation that minimizes the l(infinity) norm of the l(infinity) reprojection errors: this apparently small difference leads to a much faster but equally accurate solution which is related to the MLE under the assumption of uniform noise. The proposed method adopts a new optimisation strategy based on solving simple quadratic equations. This stands in contrast with the fastest existing methods, which solve a sequence of more complex auxiliary Linear Programming or Second Order Cone Problems. The proposed algorithm performs well: for triangulation, it achieves the same accuracy as existing techniques while executing faster and being straightforward to implement

    Variational multi-image stereo matching

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    In two-view stereo matching, the disparity of occluded pixels cannot accurately be estimated directly: it needs to be inferred through, e.g., regularisation. When capturing scenes using a plenoptic camera or a camera dolly on a track, more than two input images are available, and - contrary to the two-view case -pixels in the central view will only very rarely be occluded in all of the other views. By explicitly handling occlusions, we can limit the depth estimation of pixel (P) over right arrow to only use those cameras that actually observe (p) over right arrow. We do this by extending variational stereo matching to multiple views, and by explicitly handling occlusion on a view-by-view basis. Resulting depth maps are illustrated to be sharper and less noisy than typical recent techniques working on light fields

    Wii are out of Control: Bodies, Game Screens and the Production of Gestural Excess

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    This paper looks at the ways that the Nintendo Wii might shift the locus of game analysis away from the screen and more towards players’ corporeal relationship to the screen. The Wii hardware and software, the television screen, the physical space and players’ bodies constitute an intriguing form of kinaesthetic play that borrows from cultural fantasies about virtual reality. This play, while conditioned by the goal driven and control logics of gameplay nevertheless leads to a production of ‘gestural excess’ as bodies twist, contort and perform in ways that the game as such neither demands nor necessarily accommodates

    Indie Eh? Some Kind of Game Studies.

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    This introduction to this special issue of Loading... considers the articles of the issue in the context of game studies’ growing interest in, and implication with, the cultures of independent game development and the ‘indie scene’ in general. ‘Indie’ is the question not the answer for the authors of this issue. Together the articles herald a long term collaborative program of research that implicates concerns with the discrete and varied cultural contexts of game production, a recognition of the nuances and diversity in the tastes and values of players, and the place of digital games and game discourses in shaping and reshaping the public sphere. After this issue, we may argue about whether game studies has finally found its object but we can all agree that our engagement with the question of ‘indie’ has intriguing implications for the future of our work as games researchers, designers and cultural political actors

    Never Playing Alone: The Social Contextures of Digital Gaming

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    Digital game studies does not quite have the same legacy of metaphors as Internet studies does and to some extent we find ourselves borrowing the idea that there is the concrete material place of the user/player on the one hand and the more abstract representational space of the game on the other. If the game is online then that space (given its properties of shared visual verisimilitude, interactivity and immersion) seems in fact more cyber-spatial (in the terms described by Neal Stephenson or William Gibson) than most Internet researchers could ever imagine. It is in this sense, that massively multiplayer online games like Everquest, Star Wars Galaxies or even the Sims Online, more so than websites, MUDs or even spatially intensive games like Myst, are commonly described in terms similar to how one might describe travelling to another country. Indeed, it would seem that the more immersive the game the greater this sense of transportation becomes

    Observation of an optical event horizon in a silicon-on-insulator photonic wire waveguide

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    We report on the first experimental observation of an optical analogue of an event horizon in integrated nanophotonic waveguides, through the reflection of a continuous wave on an intense pulse. The experiment is performed in a dispersion-engineered silicon-on-insulator waveguide. In this medium, solitons do not suffer from Raman induced self-frequency shift as in silica fibers, a feature that is interesting for potential applications of optical event horizons. As shown by simulations, this also allows the observation of multiple reflections at the same time on fundamental solitons ejected by soliton fission.SCOPUS: ar.jhttp://www.opticsexpress.org/abstract.cfm?URIinfo:eu-repo/semantics/publishe

    The relationship of (perceived) epistemic cognition to interaction with resources on the internet

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    Information seeking and processing are key literacy practices. However, they are activities that students, across a range of ages, struggle with. These information seeking processes can be viewed through the lens of epistemic cognition: beliefs regarding the source, justification, complexity, and certainty of knowledge. In the research reported in this article we build on established research in this area, which has typically used self-report psychometric and behavior data, and information seeking tasks involving closed-document sets. We take a novel approach in applying established self-report measures to a large-scale, naturalistic, study environment, pointing to the potential of analysis of dialogue, web-navigation – including sites visited – and other trace data, to support more traditional self-report mechanisms. Our analysis suggests that prior work demonstrating relationships between self-report indicators is not paralleled in investigation of the hypothesized relationships between self-report and trace-indicators. However, there are clear epistemic features of this trace data. The article thus demonstrates the potential of behavioral learning analytic data in understanding how epistemic cognition is brought to bear in rich information seeking and processing tasks
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