2,330 research outputs found

    Removing other Tree Species does not benefit the Timber Species Cephalosphaera Usambarensis

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    The endemic canopy tree Cephalosphaera usambarensis is a valuable timber species in montane rainforest of Tanzania. Here we evaluate an experiment in which mature trees of species other than C. usambarensis were removed from an area in the East Usambara Mountains. We compared stage/size structure of the trees in this  area   to structure in three nearby control areas from which potential competitors had not been removed. The removal area contained a slightly higher density of large C. usambarensis trees than did control areas, but these trees had not grown bigger than those in control areas in the quarter century since removal. Furthermore, the removal area contained far fewer newly-dispersed seeds, seedlings, or small sapling trees. Thus there is no evidence that removal of potential interspecific competitors enhances the population density or biomass (tree size x density of individuals) of the C. usambarensis population. Instead, removing other trees not only sacrifices local forest biodiversity, but also may harm future timber yield of C. usambarensis by suppressing recruitment of new individuals into the population

    Determinants of treatment-related paradoxical reactions during anti-tuberculosis therapy: a case control study

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    BACKGROUND: Inflammatory response following initial improvement with anti-tuberculosis (TB) treatment has been termed a paradoxical reaction (PR). HIV co-infection is a recognised risk, yet little is known about other predictors of PR, although some biochemical markers have appeared predictive. We report our findings in an ethnically diverse population of HIV-infected and uninfected adults. METHODS: Prospective and retrospective clinical and laboratory data were collected on TB patients seen between January 1999-December 2008 at four UK centres selected to represent a wide ethnic and socio-economic mix of TB patients. Data on ethnicity and HIV status were obtained for all individuals. The associations between other potential risk factors and PR were assessed in a nested case-control study. All PR cases were matched two-to-one to controls by calendar time and centre. RESULTS: Of 1817 TB patients, 82 (4.5 %, 95 % CI 3.6-5.5 %) were identified as having a PR event. The frequency of PR was 14.4 % (18/125; 95 % CI 8.2-20.6 %) and 3.8 % (64/1692; 2.9-4.7) for HIV-positive and HIV-negative individuals respectively. There were no differences observed in PR frequency according to ethnicity, although the site was more likely to be pulmonary in those of black and white ethnicity, and lymph node disease in those of Asian ethnicity. In multivariate analysis of the case-control cohort, HIV-positive patients had five times the odds of developing PR (aOR = 5.05; 95 % CI 1.28-19.85, p = 0.028), whilst other immunosuppression e.g. diabetes, significantly reduced the odds of PR (aOR = 0.01; 0.00-0.27, p = 0.002). Patients with positive TB culture had higher odds of developing PR (aOR = 6.87; 1.31-36.04, p = 0.045) compared to those with a negative culture or those in whom no material was sent for culture. Peripheral lymph node disease increased the odds of a PR over 60-fold 4(9.60-431.25, p < 0.001). CONCLUSION: HIV was strongly associated with PR. The increased potential for PR in people with culture positive TB suggests that host mycobacterial burden might be relevant. The increased risk with TB lymphadenitis may in part arise from the visibility of clinical signs at this site. Non-HIV immunosuppression may have a protective effect. This study highlights the difficulties in predicting PR using routinely available demographic details, clinical symptoms or biochemical markers

    A Demonstration of New Techniques for Low-Cost Small House Construction

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    This study was undertaken as a field proof or demonstration of those construction techniques, design features, and structural details which have been proven through research to materially-reduce the cost or increase the quality of small house construction. As part of the study, a program was written, and a low-cost house, of approximately 1,000 sq ft of floor area (30' x 34') was designed. Variations in the placing of the house on the lot for different orientations were studied, and a site plan was made for a small development showing how these variations could be used by a builder to produce an interesting street scene.Housing and Home Finance Agenc

    Cardiogenic shock in pregnancy

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    Cardiac disease complicates 1%–4% of pregnancies globally, with a predominance in low and middle-income countries (LMICs). Increasing maternal age, rates of obesity, cardiovascular comorbidities, pre-eclampsia and gestational diabetes all contribute to acquired cardiovascular disease in pregnancy. Additionally, improved survival in congenital heart disease (CHD) has led to increasing numbers of women with CHD undergoing pregnancy. Implementation of individualised care plans formulated through pre-conception counselling and based on national and international guidance have contributed to improved clinical outcomes. However, there remains a significant proportion of women of reproductive age with no apparent comorbidities or risk factors that develop heart disease during pregnancy, with no indication for pre-conception counselling. The most extreme manifestation of cardiac disease is cardiogenic shock (CS), where the primary cardiac pathology results in inadequate cardiac output and hypoperfusion, and is associated with significant mortality and morbidity. Key to management is early recognition, intervention to treat any potentially reversible underlying pathology and supportive measures, up to and including mechanical circulatory support (MCS). In this narrative review we discuss recent developments in the classification of CS, and how these may be adapted to improve outcomes of pregnant women with, or at risk of developing, this potentially lethal condition

    The value of real-world testing: a qualitative feasibility study to explore staff and organisational barriers and strategies to support implementation of a clinical pathway for the management of anxiety and depression in adult cancer patients.

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    Background: Effective translation of evidence-based research into clinical practice requires assessment of the many factors that can impact implementation success. Research methods that draw on recognised implementation frameworks, such as the Promoting Action Research in Health Services (PARiHS) framework, and that test feasibility to gain information prior to full-scale roll-out, can support a more structured approach to implementation. Objective: This paper presents qualitative findings from a feasibility study in one cancer service of an online portal to operationalise a clinical pathway for the screening, assessment and management of anxiety and depression in adult cancer patients. The aim of this study was to explore staff perspectives on the feasibility and acceptance of a range of strategies to support implementation in order to inform the full-scale roll-out. Methods: Semi-structured interviews were conducted with fifteen hospital staff holding a range of clinical, administrative and managerial roles, and with differing levels of exposure to the pathway. Qualitative data were analysed thematically, and themes were subsequently organised within the constructs of the PARiHS framework. Results: Barriers and facilitators that affected the feasibility of the online portal and implementation strategies were organised across eight key themes: staff perceptions, culture, external influences, attitudes to psychosocial care, intervention fit, familiarity, burden and engagement. These themes mapped to the PARiHS framework's three domains of evidence, context and facilitation. Conclusions: Implementation success may be threatened by a range of factors related to the real-world context, perceptions of the intervention (evidence) and the process by which it is introduced (facilitation). Feasibility testing of implementation strategies can provide unique insights into issues likely to influence full-scale implementation, allowing for early tailoring and more effective facilitation which may save time, money and effort in the long-term. Use of a determinant implementation framework can assist researchers to synthesise and effectively respond to barriers as they arise. While the current feasibility study related to a specific implementation, strategies such as regular engagement with local stakeholders, and discussion of barriers arising in real-time during early testing is likely to be of benefit to all researchers and clinicians seeking to maximise the likelihood of long-term implementation success

    Diagnosis of Aortic Graft Infection: A Case Definition by the Management of Aortic Graft Infection Collaboration (MAGIC)

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    OBJECTIVE/BACKGROUND: The management of aortic graft infection (AGI) is highly complex and in the absence of a universally accepted case definition and evidence-based guidelines, clinical approaches and outcomes vary widely. The objective was to define precise criteria for diagnosing AGI. METHODS: A process of expert review and consensus, involving formal collaboration between vascular surgeons, infection specialists, and radiologists from several English National Health Service hospital Trusts with large vascular services (Management of Aortic Graft Infection Collaboration [MAGIC]), produced the definition. RESULTS: Diagnostic criteria from three categories were classified as major or minor. It is proposed that AGI should be suspected if a single major criterion or two or more minor criteria from different categories are present. AGI is diagnosed if there is one major plus any criterion (major or minor) from another category. (i) Clinical/surgical major criteria comprise intraoperative identification of pus around a graft and situations where direct communication between the prosthesis and a nonsterile site exists, including fistulae, exposed grafts in open wounds, and deployment of an endovascular stent-graft into an infected field (e.g., mycotic aneurysm); minor criteria are localized AGI features or fever ≥38°C, where AGI is the most likely cause. (ii) Radiological major criteria comprise increasing perigraft gas volume on serial computed tomography (CT) imaging or perigraft gas or fluid (≥7 weeks and ≥3 months, respectively) postimplantation; minor criteria include other CT features or evidence from alternative imaging techniques. (iii) Laboratory major criteria comprise isolation of microorganisms from percutaneous aspirates of perigraft fluid, explanted grafts, and other intraoperative specimens; minor criteria are positive blood cultures or elevated inflammatory indices with no alternative source. CONCLUSION: This AGI definition potentially offers a practical and consistent diagnostic standard, essential for comparing clinical management strategies, trial design, and developing evidence-based guidelines. It requires validation that is planned in a multicenter, clinical service database supported by the Vascular Society of Great Britain & Ireland

    Can compact optimisation algorithms be structurally biased?

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    In the field of stochastic optimisation, the so-called structural bias constitutes an undesired behaviour of an algorithm that is unable to explore the search space to a uniform extent. In this paper, we investigate whether algorithms from a subclass of estimation of distribution algorithms, the compact algorithms, exhibit structural bias. Our approach, justified in our earlier publications, is based on conducting experiments on a test function whose values are uniformly distributed in its domain. For the experiment, 81 combinations of compact algorithms and strategies of dealing with infeasible solutions have been selected as test cases. We have applied two approaches for determining the presence and severity of structural bias, namely an (existing) visual and an (updated) statistical (Anderson-Darling) test. Our results suggest that compact algorithms are more immune to structural bias than their counterparts maintaining explicit populations. Both tests indicate that strong structural bias is found only in the cBFO algorithm, regardless of the choice of strategy of dealing with infeasible solutions, and cPSO with mirror strategy. For other test cases, statistical and visual tests disagree on some cases classified as having mild or strong structural bias: the former one tends to make harsher decisions, thus needing further investigation

    Rare variants analysis of cutaneous malignant melanoma genes in Parkinson's disease

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    A shared genetic susceptibility between cutaneous malignant melanoma (CMM) and Parkinson's disease (PD) has been suggested. We investigated this by assessing the contribution of rare variants in genes involved in CMM to PD risk. We studied rare variation across 29 CMM risk genes using high-quality genotype data in 6875 PD cases and 6065 controls and sought to replicate findings using whole-exome sequencing data from a second independent cohort totaling 1255 PD cases and 473 controls. No statistically significant enrichment of rare variants across all genes, per gene, or for any individual variant was detected in either cohort. There were nonsignificant trends toward different carrier frequencies between PD cases and controls, under different inheritance models, in the following CMM risk genes: BAP1, DCC, ERBB4, KIT, MAPK2, MITF, PTEN, and TP53. The very rare TYR p.V275F variant, which is a pathogenic allele for recessive albinism, was more common in PD cases than controls in 3 independent cohorts. Tyrosinase, encoded by TYR, is the rate-limiting enzyme for the production of neuromelanin, and has a role in the production of dopamine. These results suggest a possible role for another gene in the dopamine-biosynthetic pathway in susceptibility to neurodegenerative Parkinsonism, but further studies in larger PD cohorts are needed to accurately determine the role of these genes/variants in disease pathogenesis
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