7,226 research outputs found

    Non-ischaemic cardiomyopathy, sudden death and implantable defibrillators: a review and meta-analysis

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    Objective: The recent Danish Study to Assess the Efficacy of ICDs in Patients with Non-ischemic Systolic Heart Failure on Mortality (DANISH) trial suggested that implantable cardioverter defibrillators (ICDs) do not reduce overall mortality in patients with non-ischaemic cardiomyopathy (NICM), despite reducing sudden cardiac death. We performed an updated meta-analysis to examine the impact of ICD therapy on mortality in NICM patients. Methods: A systematic search for studies that examined the effect of ICDs on outcomes in NICM was performed. Our analysis compared patients randomised to an ICD with those randomised to no ICD, and examined the endpoint of overall mortality. Results: Six primary prevention trials and two secondary prevention trials were identified that met the pre-specified search criteria. Using a fixed-effects model, analysis of primary prevention trials revealed a reduction in overall mortality with ICD therapy (RR 0.76, 95%ā€‰CI 0.65 to 0.91). Conclusions: Although our updated meta-analysis demonstrates a survival benefit of ICD therapy, the effect is substantively weakened by the inclusion of the DANISH trialā€”which is both the largest and most recent of the analysed trialsā€”indicating that the residual pooled benefit of ICDs may reflect the risk of sudden death in older trials which included patients treated sub-optimally by contemporary standards. As such, these data must be interpreted cautiously. The results of the DANISH trial emphasise that there is no ā€˜one size fits allā€™ indication for primary prevention ICDs in NICM patients, and clinicians must consider age and comorbidity on an individual basis when determining whether a defibrillator is appropriate

    Spatial variability in condition of southern rock lobsters (Jasus edwardsii) at the start of the Tasmanian fishing season

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    This research was funded by the Australian Seafood Cooperative Research Centre and the Fisheries Research and Development Corporation (project number 2014/726) (http://www.seafoodcrc.com/) (http://frdc.com.au/Pages/home.aspx). The Australian Research Council's Industrial Transformation Research Program (project number IH120100032) is gratefully acknowledged for providing further financial support for two authors to present this work at the Crustacean Society and International Association of Astacology Mid-year Meeting, 19-23 July 2015 (http://www.arc.gov.au/industrial-transformation-research-programme).The southern rock lobster (Jasus edwardsii) industry in Australia favours red lobsters, which are usually caught in shallow waters, over paler (brindle) lobsters. This preference is driven partly by the Chinese market, where red is associated with luck and prosperity, and additionally, by the widely held perception within the industry that brindles have greater mortality rates during out of water transport than reds. Limited scientific evidence supports these industry observations; however, these studies did not evaluate the initial condition of lobsters. This study aimed first, to determine which variables better describe condition in J. edwardsii and second, to compare condition among lobsters in several sites around Tasmania at the typical time of high transport mortality. Male lobsters were collected from the South West, South East, East and North coast of Tasmania in late November/December 2014, which correspond to the start of the Tasmanian fishing season. A comprehensive condition assessment was applied by measuring tissue proximal composition, Brix index, Total Haemocyte Count, pH, haemocyanin and another 16 haemolymph parameters of interest. A useful framework to compare condition in J. edwardsii was established by first, using Brix index as a measure of nutritional condition, second, using pH, magnesium, and bicarbonate to evaluate differences in physiological condition and finally, using THC counts as a proxy for lobster health condition. Lobsters from different sites had different nutritional, physiological and health condition, consistent with industry observations, however our results indicate that some red shallow water lobsters exhibited poorer nutritional and health condition, while some deep water brindle lobsters were in good condition. Differences in condition could not be directly associated to catch depth of lobsters and was related to other spatially discrete factors which sometimes vary over distances <3 km.Publisher PDFPeer reviewe

    A method for dense packing discovery

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    The problem of packing a system of particles as densely as possible is foundational in the field of discrete geometry and is a powerful model in the material and biological sciences. As packing problems retreat from the reach of solution by analytic constructions, the importance of an efficient numerical method for conducting \textit{de novo} (from-scratch) searches for dense packings becomes crucial. In this paper, we use the \textit{divide and concur} framework to develop a general search method for the solution of periodic constraint problems, and we apply it to the discovery of dense periodic packings. An important feature of the method is the integration of the unit cell parameters with the other packing variables in the definition of the configuration space. The method we present led to improvements in the densest-known tetrahedron packing which are reported in [arXiv:0910.5226]. Here, we use the method to reproduce the densest known lattice sphere packings and the best known lattice kissing arrangements in up to 14 and 11 dimensions respectively (the first such numerical evidence for their optimality in some of these dimensions). For non-spherical particles, we report a new dense packing of regular four-dimensional simplices with density Ļ•=128/219ā‰ˆ0.5845\phi=128/219\approx0.5845 and with a similar structure to the densest known tetrahedron packing.Comment: 15 pages, 5 figure

    Novel muon imaging techniques

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    Owing to the high penetrating power of high-energy cosmic ray muons, muon imaging techniques can be used to image large bulky objects, especially objects with heavy shielding. Muon imaging systems work just like CT scanners in the medical imaging fieldā€”that is, they can reveal information inside of a target. There are two forms of muon imaging techniques: muon absorption imaging and muon multiple scattering imaging. The former is based on the flux attenuation of muons, and the latter is based on the multiple scattering of muons in matter. The muon absorption imaging technique is capable of imaging very large objects such as volcanoes and large buildings, and also smaller objects like spent fuel casks; the muon multiple scattering imaging technique is best suited to inspect smaller objects such as nuclear waste containers. Muon imaging techniques can be applied in a broad variety of fields, i.e. from measuring the magma thickness of volcanoes to searching for secret cavities in pyramids, and from monitoring the borders of countries checking for special nuclear materials to monitoring the spent fuel casks for nuclear safeguards applications. In this paper, the principles of muon imaging are reviewed. Image reconstruction algorithms such as Filtered Back Projection and Maximum Likelihood Expectation Maximization are discussed. The capability of muon imaging techniques is demonstrated through a Geant4 simulation study for imaging a nuclear spent fuel cask

    Polarisation observables in neutral pion photoproduction with MAMI

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    This thesis presents new high statistics measurements of polarisation observables in neutral pion photoproduction from experiments carried out with the Crystal Ball at the Mainzer Microtron (MAMI) in Mainz. The polarisation observable Ī£ has been measured in the Ī³p ā†’ Ļ€0 p reaction in the region between the āˆ†(1232) and second resonance region. Measurements of observables Ī£, I s and I c in the Ī³p ā†’ 2Ļ€0 p reaction have been made from the 2Ļ€ 0 threshold, a lower energy than previously measured. All measurements produced for this thesis have been sent to partial wave analysis groups where they will be used to provide constraints to their models. In particular, the 2Ļ€ 0 measurements are expected to have an impact on our understanding of the poorly constrained properties of the N(1440) resonance, such as the branching ratios of its decay through intermediate meson or āˆ† pathways. The sPlot technique has been used for the first time in photoproduction experiments with advantages over other techniques discussed. The development of the technique for such analysis as this will be key for the extraction of many observables from future measurements

    Optimising the activities and the products of academic and student collaborative networks to achieve equality, diversity and inclusion goals in higher education

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    The student and staff experience within Middlesex University (MDX) is of paramount importance to all teaching and learning staff in the Adult, Child and Mental Health Nursing and Midwifery Department. Students are predominantly black and minority ethnic (BME) and also culturally and linguistically diverse, speaking as many as four languages in addition to the mother tongue. Student expectations and anxiety are centred on the experiences of the existing partnership and learning relationships that they have with BME lecturers. The purpose of this article is to present a case study of the lived experiences of BME staff and students when formulating networks; it is authored by students and lecturers from the ā€˜Healthcare Academics Race Equality, Diversity and Inclusivity Network and Strategic Advisory Groupā€™ (HAREDIN and SAG) and the student mirror network, ā€˜Student Healthcare Academics Race Equality, Diversity and Inclusivity Networkā€™ (SHAREDIN)

    Chronic heart failure: epidemiology, investigation and management

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    Heart failure (HF) is a clinical syndrome characterized by dyspnoea, fatigue and fluid retention accompanied by objective evidence of cardiac dysfunction. The syndrome affects around 2% of the adult population, men more commonly than women (&lt;80 years old), with the incidence and prevalence rising steeply with age. HF causes substantial morbidity and reduced life expectancy, and coronary artery disease accounts for two-thirds of cases in developed countries. Investigation is important to ascertain the diagnosis, identify the aetiology (which may be reversible) and give some indication of prognosis. The diagnosis of HF confers a significantly increased risk of hospital admission and death. Treatment has been revolutionized by large randomized controlled clinical trials studying the effects of antagonists of the reninā€“angiotensinā€“aldosterone, neutral endopeptidase and sympathetic nervous systems, and the effects of device therapy. Cardiac transplantation remains an option for patients who are severely symptomatic (and at high risk) despite optimal use of such therapy

    Who benefits from a defibrillatorā€”balancing the risk of sudden versus non-sudden death

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    Purpose of Review: Treatment with a defibrillator can reduce the risk of sudden death by terminating ventricular arrhythmias. The identification of patient groups in whom this function reduces overall mortality is challenging. In this review, we summarise the evidence for who benefits from a defibrillator. Recent Findings: Recent evidence suggests that contemporary pharmacologic and non-defibrillator device therapies are altering the potential risks and benefits of a defibrillator. Summary: Who benefits from a defibrillator is determined by both the risk of sudden death and the competing risk of other, non-sudden causes of death. The balance of these risks is changing, which calls into question whether historic evidence for the use of defibrillators remains robust in the modern era
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