5,850 research outputs found

    Briefing: Auditor/company interactions in the 2007 UK regulatory environment

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    Clinical surveillance of thrombotic microangiopathies in Scotland, 2003-2005

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    The prevalence, incidence and outcomes of haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP) are not well established in adults or children from prospective studies. We sought to identify both outcomes and current management strategies using prospective, national surveillance of HUS and TTP, from 2003 to 2005 inclusive. We also investigated the links between these disorders and factors implicated in the aetiology of HUS and TTP including infections, chemotherapy, and immunosuppression. Most cases of HUS were caused by verocytotoxin-producing Escherichia coli (VTEC), of which serotype O157 predominated, although other serotypes were identified. The list of predisposing factors for TTP was more varied although use of immunosuppressive agents and severe sepsis, were the most frequent precipitants. The study demonstrates that while differentiating between HUS and TTP is sometimes difficult, in most cases the two syndromes have quite different predisposing factors and clinical parameters, enabling clinical and epidemiological profiling for these disorders

    Boundary spanning and gatekeeping roles of UK audit committees

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    Post-financial crisis, audit committee (AC) reforms are proposed to improve the quality of financial reporting.†† The editorial process for this paper was undertaken by Pauline Weetman, former ABR editor. This paper's empirical contribution is to investigate the extent to which ACs and audit committee chairs (ACCs) engage with chief financial officers (CFOs) and audit partners (APs) across a range of 32 financial reporting issues. It is the first large-scale survey of interactions to move beyond the micro-CFO/AP dyad and to distinguish the individual ACC from the AC group. While 37% of the 5445 reported discussions involve all three key individuals together with the full AC, 35% involve neither the AC nor the ACC and the ACC acts without the full AC in a significant minority of cases. The parties reported to be involved are similar across the three respondent groups but vary with financial reporting issue, company size and audit firm size. The paper's theoretical contribution is to interpret the evidence using the concepts of boundary spanning and gatekeeping roles. The research reveals incomplete levels of AC and ACC engagement with financial reporting issues. Findings have implications for policy-makers regarding the role, influence and effectiveness of the AC in financial reporting matters. Directions for future research are identified

    Contragredient Transformations Applied to the Optimal Projection Equations

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    The optimal projection approach to solving the H2 reduced order model problem produces two coupled, highly nonlinear matrix equations with rank conditions as constraints. It is not obvious from their original form how they can be differentiated and how some algorithm for solving nonlinear equations can be applied to them. A contragredient transformation, a transformation which simultaneously diagonalizes two symmetric positive semi-definite matrices, is used to transform the equations into forms suitable for algorithms for solving nonlinear problems. Three different forms of the equations obtained using contragredient transformations are given. An SVD-based algorithm for the contragredient transformation and a homotopy algorithm for the transformed equations are given, together with a numerical example

    Sites of Biosynthesis of Outer and Inner Membrane Proteins of Neurospora crassa Mitochondria

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    Outer and inner membranes of Neurospora crassa mitochondria were separated by the combined swelling, shrinking, sonication procedure. Membranes were characterized by electron microscopy and by marker enzyme activities. A red carotenoid pigment was found to be concentrated in the outer membrane. The inner mitochondrial membrane was resolved into about 20 protein bands on polyacrylamide gel electrophoresis, whereas the outer membrane shows essentially one single protein band. Only negligible incorporation of radioactive amino acids occurs into outer membrane when isolated mitochondria are synthesizing polypeptide chains. In agreement with this observation labeling of outer membrane protein is almost entirely blocked, when whole Neurospora cells are incubated with radioactive amino acids in the presence of cycloheximide, an inhibitor of cytoplasmic protein synthesis. Finally, the essential electrophoretic protein band from outer membrane does not become labeled when mitochondria are incubated with radioactive amino acids either in vitro or in vivo in the presence of cycloheximide. It is concluded that the vast majority, if not all, of the outer membrane protein is synthesized by the cytoplasmic system and that polypeptide chains formed by the mitochondrial ribosomes are integrated into the inner mitochondrial membrane

    Generation and Characterization of a genetic zebrafish model of SMA carrying the human SMN2 gene

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    <p>Abstract</p> <p>Background</p> <p>Animal models of human diseases are essential as they allow analysis of the disease process at the cellular level and can advance therapeutics by serving as a tool for drug screening and target validation. Here we report the development of a complete genetic model of spinal muscular atrophy (SMA) in the vertebrate zebrafish to complement existing zebrafish, mouse, and invertebrate models and show its utility for testing compounds that alter <it>SMN2 </it>splicing.</p> <p>Results</p> <p>The human motoneuron disease SMA is caused by low levels, as opposed to a complete absence, of the survival motor neuron protein (SMN). To generate a true model of SMA in zebrafish, we have generated a transgenic zebrafish expressing the human <it>SMN2 </it>gene (<it>hSMN2</it>), which produces only a low amount of full-length SMN, and crossed this onto the <it>smn</it><sup>-/- </sup>background. We show that human <it>SMN2 </it>is spliced in zebrafish as it is in humans and makes low levels of SMN protein. Moreover, we show that an antisense oligonucleotide that enhances correct <it>hSMN2 </it>splicing increases full-length <it>hSMN </it>RNA in this model. When we placed this transgene on the <it>smn </it>mutant background it rescued the neuromuscular presynaptic SV2 defect that occurs in <it>smn </it>mutants and increased their survival.</p> <p>Conclusions</p> <p>We have generated a transgenic fish carrying the human <it>hSMN2 </it>gene. This gene is spliced in fish as it is in humans and mice suggesting a conserved splicing mechanism in these vertebrates. Moreover, antisense targeting of an intronic splicing silencer site increased the amount of full length SMN generated from this transgene. Having this transgene on the <it>smn </it>mutant fish rescued the presynaptic defect and increased survival. This model of zebrafish SMA has all of the components of human SMA and can thus be used to understand motoneuron dysfunction in SMA, can be used as an vivo test for drugs or antisense approaches that increase full-length SMN, and can be developed for drug screening.</p

    Macrophage transactivation for chemokine production identified as a negative regulator of granulomatous inflammation using agent-based modeling

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    Cellular activation in trans by interferons, cytokines and chemokines is a commonly recognized mechanism to amplify immune effector function and limit pathogen spread. However, an optimal host response also requires that collateral damage associated with inflammation is limited. This may be particularly so in the case of granulomatous inflammation, where an excessive number and / or excessively florid granulomas can have significant pathological consequences. Here, we have combined transcriptomics, agent-based modeling and in vivo experimental approaches to study constraints on hepatic granuloma formation in a murine model of experimental leishmaniasis. We demonstrate that chemokine production by non-infected Kupffer cells in the Leishmania donovani-infected liver promotes competition with infected KCs for available iNKT cells, ultimately inhibiting the extent of granulomatous inflammation. We propose trans-activation for chemokine production as a novel broadly applicable mechanism that may operate early in infection to limit excessive focal inflammation

    Violence against female sex workers in Karnataka state, south India: impact on health, and reductions in violence following an intervention program.

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    ABSTRACT: BACKGROUND: Violence against female sex workers (FSWs) can impede HIV prevention efforts and contravenes their human rights. We developed a multi-layered violence intervention targeting policy makers, secondary stakeholders (police, lawyers, media), and primary stakeholders (FSWs), as part of wider HIV prevention programming involving &gt;60,000 FSWs in Karnataka state. This study examined if violence against FSWs is associated with reduced condom use and increased STI/HIV risk, and if addressing violence against FSWs within a large-scale HIV prevention program can reduce levels of violence against them. METHODS: FSWs were randomly selected to participate in polling booth surveys (PBS 2006-2008; short behavioural questionnaires administered anonymously) and integrated behavioural-biological assessments (IBBAs 2005-2009; administered face-to-face). RESULTS: 3,852 FSWs participated in the IBBAs and 7,638 FSWs participated in the PBS. Overall, 11.0% of FSWs in the IBBAs and 26.4% of FSWs in the PBS reported being beaten or raped in the past year. FSWs who reported violence in the past year were significantly less likely to report condom use with clients (zero unprotected sex acts in previous month, 55.4% vs. 75.5%, adjusted odds ratio (AOR) 0.4, 95% confidence interval (CI) 0.3 to 0.5, p &lt; 0.001); to have accessed the HIV intervention program (ever contacted by peer educator, 84.9% vs. 89.6%, AOR 0.7, 95% CI 0.4 to 1.0, p = 0.04); or to have ever visited the project sexual health clinic (59.0% vs. 68.1%, AOR 0.7, 95% CI 0.6 to 1.0, p = 0.02); and were significantly more likely to be infected with gonorrhea (5.0% vs. 2.6%, AOR 1.9, 95% CI 1.1 to 3.3, p = 0.02). By the follow-up surveys, significant reductions were seen in the proportions of FSWs reporting violence compared with baseline (IBBA 13.0% vs. 9.0%, AOR 0.7, 95% CI 0.5 to 0.9 p = 0.01; PBS 27.3% vs. 18.9%, crude OR 0.5, 95% CI 0.4 to 0.5, p &lt; 0.001). CONCLUSIONS: This program demonstrates that a structural approach to addressing violence can be effectively delivered at scale. Addressing violence against FSWs is important for the success of HIV prevention programs, and for protecting their basic human rights

    Interpolatory methods for H\mathcal{H}_\infty model reduction of multi-input/multi-output systems

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    We develop here a computationally effective approach for producing high-quality H\mathcal{H}_\infty-approximations to large scale linear dynamical systems having multiple inputs and multiple outputs (MIMO). We extend an approach for H\mathcal{H}_\infty model reduction introduced by Flagg, Beattie, and Gugercin for the single-input/single-output (SISO) setting, which combined ideas originating in interpolatory H2\mathcal{H}_2-optimal model reduction with complex Chebyshev approximation. Retaining this framework, our approach to the MIMO problem has its principal computational cost dominated by (sparse) linear solves, and so it can remain an effective strategy in many large-scale settings. We are able to avoid computationally demanding H\mathcal{H}_\infty norm calculations that are normally required to monitor progress within each optimization cycle through the use of "data-driven" rational approximations that are built upon previously computed function samples. Numerical examples are included that illustrate our approach. We produce high fidelity reduced models having consistently better H\mathcal{H}_\infty performance than models produced via balanced truncation; these models often are as good as (and occasionally better than) models produced using optimal Hankel norm approximation as well. In all cases considered, the method described here produces reduced models at far lower cost than is possible with either balanced truncation or optimal Hankel norm approximation
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