294 research outputs found

    Exploring the non-invasive diagnosis of bladder outlet obstruction using a penile cuff.

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    Introduction: It has been proposed that all men should undergo invasive pressure flow studies (PFS) prior to bladder outlet surgery. However, expense and morbidity limit the use of this investigation. A non-invasive technique for measuring bladder contractility using controlled inflation of a penile cuff has been developed. In work in an experimental model there is also evidence to suggest that this technique may be used to measure urethral opening pressure. The purpose of this thesis is to validate the penile cuff technique and to confirm whether this may used to diagnose bladder outlet obstruction (BOO) and obviate the need for invasive PFS prior to bladder outlet surgery. We also aim to elucidate whether cuff measurements can provide a non-invasive estimation of urethral opening pressure. Methods: 118 patients were investigated with free flow rates, invasive pressure flow studies, free cuff test, simultaneous cuff test and invasive PFS, and voiding urethral pressure profile (VUPP) measurements. Cuff pressure at flow interruption "pcuff.int" was compared with isovolumetric bladder pressure as a measure of bladder contractility. This was then used in conjunction with urinary flow rate to test a proposed non-invasive nomogram for diagnosis of bladder outlet obstruction. Cuff pressure at which flow rate starts to fall "pcuffknee", proposed as a measure of urethral opening pressure, was compared with estimations of urethral opening pressure taken from invasive pressure flow studies and VUPP's. Results: pcuff.int provides a valid estimation of isovolumetric bladder pressure. When used in combination with flow rate measurements this can be used to diagnose or exclude BOO in approximately two thirds of men, using a modification of the ICS nomogram. Although pcuff.knee does not correspond precisely with the previously described measures of urethral opening pressure, there is reasonable evidence to support our hypothesis that Pcuff knee may provide a simple and non-invasive estimation of urethral opening pressure

    On the automatic construction of indistinguishable operations

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    An increasingly important design constraint for software running on ubiquitous computing devices is security, particularly against physical methods such as side-channel attack. One well studied methodology for defending against such attacks is the concept of indistinguishable functions which leak no information about program control flow since all execution paths are computationally identical. However, constructing such functions by hand becomes laborious and error prone as their complexity increases. We investigate techniques for automating this process and find that effective solutions can be constructed with only minor amounts of computational effort.Fundação para a CiĂȘncia e Tecnologia - SFRH/BPD/20528/2004

    Species trait selection along a prescribed fire chronosequence

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    1. Fire is a widespread management practice used in the maintenance of European heathland. Frequent prescribed burns in small patches have been shown to benefit carabid communities; however, how fire favours specific life-history traits is poorly understood. 2. In this study, we identify characteristic species of the successional stages within heathlands, and find the traits which are characteristic of species in burnt areas versus areas dominated by older heath stands. 3. We identify 10 species as indicator species for heathland in the pioneer stage (0–5 years old); Amara lunicollis, Bembidion lampros, Calathus fuscipes, Carabus problematicus, Cicindela campestris, Nebria salina, Notiophilus aquaticus, Poecilus cupreus, P. lepidus and P. versicolor. Dyschirius globosus is identified as an indicator for the building stage (6–14 years old), and Carabus violaceus as an indicator for the mature stage (15–25 years old). 4. Moisture preference and diet are identified as traits that determine species response to prescribed fire. Collembolan specialists and species with no moisture preference are shown to be most abundant in burnt patches, whereas generalist predators and species with a high moisture preference are less tolerant of fire. 5. Knowledge of species sorting along a prescribed fire gradient can provide valuable information for heathland conservation.publishedVersio

    On the Selection of Pairing-Friendly Groups

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    We propose a simple algorithm to select group generators suitable for pairing-based cryptosystems. The selected parameters are shown to favor implementations of the Tate pairing that are at once conceptually simple and efficient, with an observed performance about 2 to 10 times better than previously reported implementations, depending on the embedding degree. Our algorithm has beneficial side effects: various non-pairing operations become faster, and bandwidth may be saved

    Electronic properties of germanane field-effect transistors

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    A new two dimensional (2D) material—germanane—has been synthesised recently with promising electrical and optical properties. In this paper we report the first realisation of germanane field-effect transistors fabricated from multilayer single crystal flakes. Our germanane devices show transport in both electron and hole doped regimes with on/off current ratio of up to 10e5(10e4) and carrier mobilities of 150  cm2 (Vs)−1(70 cm2 (Vs)−1) at 77 K (room temperature). A significant enhancement of the device conductivity under illumination with 650 nm red laser is observed. Our results reveal ambipolar transport properties of germanane with great potential for (opto)electronics applications

    Promoter prediction using physico-chemical properties of DNA

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    The ability to locate promoters within a section of DNA is known to be a very difficult and very important task in DNA analysis. We document an approach that incorporates the concept of DNA as a complex molecule using several models of its physico-chemical properties. A support vector machine is trained to recognise promoters by their distinctive physical and chemical properties. We demonstrate that by combining models, we can improve upon the classification accuracy obtained with a single model. We also show that by examining how the predictive accuracy of these properties varies over the promoter, we can reduce the number of attributes needed. Finally, we apply this method to a real-world problem. The results demonstrate that such an approach has significant merit in its own right. Furthermore, they suggest better results from a planned combined approach to promoter prediction using both physicochemical and sequence based techniques

    RE: pedagogy – after neutrality

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    Within the UK and in many parts of the world, official accounts of what it is to make sense of religion are framed within a rhetorics of neutrality in which such study is premised upon the possibility of dispassionate engagement and analysis. This paper, which is largely theoretical in scope, explores both the affordances and the costs of such an approach which has become ‘black boxed’ on account of the work that it achieves. A series of new orientations within the academy that are broadly associated with post-structuralist philosophies, feminist and post-colonial studies, together with insights from Science and Technology Studies, question the plausibility of these claims for neutrality whilst in turn raising a series of new questions and priorities. It therefore becomes necessary to re-think and re-frame what it is to make sense of religious and cultural difference after neutrality. The gathering and co-ordination of new planes of sense-making that are responsive to an emergent series of epistemological, ontological, and ethical orientations are considered. Some of the distinctive pedagogical implications of such an approach that engages material practice, difference and uncertainty are then entertained
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