4,462 research outputs found

    The factorization of M-channel FIR and IIR cosine-modulated filter banks and their multiplier-less realizations using sopot coefficients

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    The 47th Midwest Symposium on Circuits and Systems Conference Proceedings, Salt Lake City, Utah, USA, 25-28 July 2004This paper proposes a new factorization for the M-channel perfect reconstruction (PR) IIR Cosine-Modulated filter banks (CMFB) proposed previously by the authors. This factorization, which is based on the lifting scheme, is also complete for the PR FIR CMFB as well as the general two-channel PR IIR filter banks if the determinant of the polyphase matrix is equal to constant multiplies of signal delays. It can be used to convert a numerically optimized nearly PR CMFB to a structurally PR system. Furthermore, the arithmetic complexity of the FB using this structure can be reduced asymptotically by a factor of two. When the forward and inverse transforms are implemented with the same set of SOPOT coefficients, a multiplier-less CMFB can be obtained. Its arithmetic complexity is further reduced and it becomes very attractive for VLSI implementation.published_or_final_versio

    The Algal Chloroplast as a Testbed for Synthetic Biology Designs Aimed at Radically Rewiring Plant Metabolism

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    Sustainable and economically viable support for an ever-increasing global population requires a paradigm shift in agricultural productivity, including the application of biotechnology to generate future crop plants. Current genetic engineering approaches aimed at enhancing the photosynthetic efficiency or composition of the harvested tissues involve relatively simple manipulations of endogenous metabolism. However, radical rewiring of central metabolism using new-to-nature pathways, so-called "synthetic metabolism", may be needed to really bring about significant step changes. In many cases, this will require re-programming the metabolism of the chloroplast, or other plastids in non-green tissues, through a combination of chloroplast and nuclear engineering. However, current technologies for sophisticated chloroplast engineering ("transplastomics") of plants are limited to just a handful of species. Moreover, the testing of metabolic rewiring in the chloroplast of plant models is often impractical given their obligate phototrophy, the extended time needed to create stable non-chimeric transplastomic lines, and the technical challenges associated with regeneration of whole plants. In contrast, the unicellular green alga, Chlamydomonas reinhardtii is a facultative heterotroph that allows for extensive modification of chloroplast function, including non-photosynthetic designs. Moreover, chloroplast engineering in C. reinhardtii is facile, with the ability to generate novel lines in a matter of weeks, and a well-defined molecular toolbox allows for rapid iterations of the "Design-Build-Test-Learn" (DBTL) cycle of modern synthetic biology approaches. The recent development of combinatorial DNA assembly pipelines for designing and building transgene clusters, simple methods for marker-free delivery of these clusters into the chloroplast genome, and the pre-existing wealth of knowledge regarding chloroplast gene expression and regulation in C. reinhardtii further adds to the versatility of transplastomics using this organism. Herein, we review the inherent advantages of the algal chloroplast as a simple and tractable testbed for metabolic engineering designs, which could then be implemented in higher plants

    Observation of the Kibble-Zurek Mechanism in Microscopic Acoustic Crackling Noises

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    Characterizing the fast evolution of microstructural defects is key to understanding “crackling” phenomena during the deformation of solid materials. For example, it has been proposed using atomistic simulations of crack propagation in elastic materials that the formation of a nonlinear hyperelastic or plastic zone around moving crack tips controls crack velocity. To date, progress in understanding the physics of this critical zone has been limited due to the lack of data describing the complex physical processes that operate near microscopic crack tips. We show, by analyzing many acoustic emission events during rock deformation experiments, that the signature of this nonlinear zone maps directly to crackling noises. In particular, we characterize a weakening zone that forms near the moving crack tips using functional networks and we determine the scaling law between the formation of damages (defects) and the traversal rate across the critical point of transition. Moreover, we show that the correlation length near the transition remains effectively frozen. This is the main underlying hypothesis behind the Kibble-Zurek mechanism (KZM) and the obtained power-law scaling verifies the main prediction of KZM

    The effect of azithromycin in adults with stable neutrophilic COPD: A double blind randomised, placebo controlled trial

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    Background: Chronic Obstructive Pulmonary Disease (COPD) is a progressive airway disease characterised by neutrophilic airway inflammation or bronchitis. Neutrophilic bronchitis is associated with both bacterial colonisation and lung function decline and is common in exacerbations of COPD. Despite current available therapies to control inflammation, neutrophilic bronchitis remains common. This study tested the hypothesis that azithromycin treatment, as an add-on to standard medication, would significantly reduce airway neutrophil and neutrophils chemokine (CXCL8) levels, as well as bacterial load. We conducted a randomised, double-blind, placebo-controlled study in COPD participants with stable neutrophilic bronchitis. Methods: Eligible participants (n = 30) were randomised to azithromycin 250 mg daily or placebo for 12 weeks in addition to their standard respiratory medications. Sputum was induced at screening, randomisation and monthly for a 12 week treatment period and processed for differential cell counts, CXCL8 and neutrophil elastase assessment. Quantitative bacteriology was assessed in sputum samples at randomisation and the end of treatment visit. Severe exacerbations where symptoms increased requiring unscheduled treatment were recorded during the 12 week treatment period and for 14 weeks following treatment. A sub-group of participants underwent chest computed tomography scans (n = 15). Results: Nine participants with neutrophilic bronchitis had a potentially pathogenic bacteria isolated and the median total bacterial load of all participants was 5.22×107 cfu/mL. Azithromycin treatment resulted in a non-significant reduction in sputum neutrophil proportion, CXCL8 levels and bacterial load. The mean severe exacerbation rate was 0.33 per person per 26 weeks in the azithromycin group compared to 0.93 exacerbations per person in the placebo group (incidence rate ratio (95%CI): 0.37 (0.11,1.21), p = 0.062). For participants who underwent chest CT scans, no alterations were observed. Conclusions: In stable COPD with neutrophilic bronchitis, add-on azithromycin therapy showed a trend to reduced severe exacerbations sputum neutrophils, CXCL8 levels and bacterial load. Future studies with a larger sample size are warranted. Trial Registration: Australian New Zealand Clinical Trials Registry ACTRN12609000259246. © 2014 Simpson et al

    Navigating the journey of Aboriginal childhood disability: a qualitative study of carers' interface with services

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    © 2016 The Author(s) Background: The disadvantage experienced by Aboriginal and Torres Strait Islander children with a disability is well recognized. The long term consequences of failing to address disability on health, education and employment underlies the importance of early intervention. Caregivers experience a disproportionate burden and have challenges accessing services. The aim of this study was to describe the carer journey of accessing support and services. Methods: We conducted in-depth semi-structured interviews with nineteen parents and carers of Aboriginal children aged 0-8 years. The children were patients at a child developmental clinic at a metropolitan area Aboriginal health service in Eastern Australia. Interpretive phenomenological analysis was applied to transcribed verbatim accounts. Results: Four themes were developed using the 'journey' metaphor to describe the carer pathway of accessing support and services at the community, service and policy levels. Themes included 1) the need for increased signage within communities via community education, information and awareness, 2) wrong way signs, roundabouts and roadblocks encountered when accessing services, 3) alternate routes can facilitate the journey, and 4) incompatibility of inflexible bureaucratic road rules and lived realities. Conclusions: The challenges of caring for a child with a disability are indisputable and these can be compounded for people experiencing socio-economic disadvantage and marginalisation. Overcoming challenges to service access faced by carers of Aboriginal children with a disability will require investment in community, services and policy to tailor culturally appropriate models of care

    Interacting With Providers: An Intersectional Exploration of the Experiences of Carers of Aboriginal Children With a Disability

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    © The Author(s) 2018. Intersectionality has potential to create new ways to describe disparities and craft meaningful solutions. This study aimed to explore Aboriginal carers’ experiences of interactions with health, social, and education providers in accessing services and support for their child. Carers of Aboriginal children with a disability were recruited from an Australian metropolitan Aboriginal community-controlled health service. In-depth, semistructured interviews were conducted with 19 female carers. Intersectionality was applied as an analytical framework due to the inherent power differentials for Aboriginal Australians and carers for people with a disability. Marginalization and a lack of empowerment were evident in the experiences of interactions with providers due to cultural stereotypes and racism, lack of cultural awareness and sensitivity, and poverty and homelessness. Community-led models of care can help overcome the intersectional effects of these identities and forms of oppression in carers’ interactions with providers and enhance access to care

    Experiences and needs of carers of Aboriginal children with a disability: A qualitative study

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    © 2017 The Author(s). Background: Australian parents/carers of a person with a disability experience higher rates of depression, more financial stress, and are twice as likely to be in poor physical health than the general population. Aboriginal and Torres Strait Islander peoples experience worse health, social and economic outcomes than other Australians, and those with a disability face 'double disadvantage'. This study aimed to better understand the experiences and needs of parents/carers/families of Aboriginal children with a disability. Methods: Semi-structured in-depth interviews were conducted with parents or primary carers of Aboriginal children aged zero-eight with disability. Interviews were analysed using thematic analysis. Results: Nineteen women (sixteen mothers and three grandmothers) were interviewed. More than half were lone carers (without a partner or spouse). Participants described their experiences, including challenges and facilitators, to providing and accessing care, impacts on their health and wellbeing, and associated economic and non-economic costs of caregiving. Financial strain and social isolation was particularly prominent for lone carers. Conclusions: Tailoring services to the needs of carers of Aboriginal children with a disability means supporting kinship caregiving, facilitating engagement with other Aboriginal families, and streamlining services and systems to mitigate costs. The experiences described by our participants depict an intersection of race, socio-economic status, gender, disability, and caregiving. Services and funding initiatives should incorporate such intersecting determinants in planning and delivery of holistic care

    Uniqueness of Gibbs Measure for Models With Uncountable Set of Spin Values on a Cayley Tree

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    We consider models with nearest-neighbor interactions and with the set [0,1][0,1] of spin values, on a Cayley tree of order k≥1k\geq 1. It is known that the "splitting Gibbs measures" of the model can be described by solutions of a nonlinear integral equation. For arbitrary k≥2k\geq 2 we find a sufficient condition under which the integral equation has unique solution, hence under the condition the corresponding model has unique splitting Gibbs measure.Comment: 13 page

    Prediction of sarcomere mutations in subclinical hypertrophic cardiomyopathy.

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    BACKGROUND: Sarcomere protein mutations in hypertrophic cardiomyopathy induce subtle cardiac structural changes before the development of left ventricular hypertrophy (LVH). We have proposed that myocardial crypts are part of this phenotype and independently associated with the presence of sarcomere gene mutations. We tested this hypothesis in genetic hypertrophic cardiomyopathy pre-LVH (genotype positive, LVH negative [G+LVH-]). METHODS AND RESULTS: A multicenter case-control study investigated crypts and 22 other cardiovascular magnetic resonance parameters in subclinical hypertrophic cardiomyopathy to determine their strength of association with sarcomere gene mutation carriage. The G+LVH- sample (n=73) was 29 ± 13 years old and 51% were men. Crypts were related to the presence of sarcomere mutations (for ≥1 crypt, β=2.5; 95% confidence interval [CI], 0.5-4.4; P=0.014 and for ≥2 crypts, β=3.0; 95% CI, 0.8-7.9; P=0.004). In combination with 3 other parameters: anterior mitral valve leaflet elongation (β=2.1; 95% CI, 1.7-3.1; P<0.001), abnormal LV apical trabeculae (β=1.6; 95% CI, 0.8-2.5; P<0.001), and smaller LV end-systolic volumes (β=1.4; 95% CI, 0.5-2.3; P=0.001), multiple crypts indicated the presence of sarcomere gene mutations with 80% accuracy and an area under the curve of 0.85 (95% CI, 0.8-0.9). In this G+LVH- population, cardiac myosin-binding protein C mutation carriers had twice the prevalence of crypts when compared with the other combined mutations (47 versus 23%; odds ratio, 2.9; 95% CI, 1.1-7.9; P=0.045). CONCLUSIONS: The subclinical hypertrophic cardiomyopathy phenotype measured by cardiovascular magnetic resonance in a multicenter environment and consisting of crypts (particularly multiple), anterior mitral valve leaflet elongation, abnormal trabeculae, and smaller LV systolic cavity is indicative of the presence of sarcomere gene mutations and highlights the need for further study

    Electrified plasma in AdS/CFT correspondence

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    We construct new gravity backgrounds holographic dual to neutral plasma with U(1) global symmetry in the presence of constant electric field, considering its full back-reactions to the metric. As the electric field and the induced current cause a net energy in-flow to the system, the plasma is continually heated up and the corresponding gravity solution has an expanding horizon. After proposing a consistent late-time expansion scheme, we present analytic solutions in the scheme up to next-leading order, and our solutions are new time-dependent solutions of 5D asymptotic AdS Einstein-Maxwell(-Chern-Simons) theory. To extract dual CFT stress tensor and U(1) current from the solutions, we perform a rigorous holographic renormalization of Einstein-Maxwell-Chern-Simons theory including full back-reactions, which can in itself be an interesting addition to literatures. As by-products, we obtain interesting modifications of energy-momentum/current Ward identities due to the U(1) symmetry and its triangle anomaly.Comment: 27 pages, no figure, v3, minor typos fixed, matches with published versio
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