275 research outputs found

    Is there a close association between "soils" and "vegetation"? : A case study from central western New South Wales

    Get PDF
    The assumption that ‘soils’ and ‘vegetation’ are closely associated was tested by describing soils and vegetation along a Travelling Stock Reserve west of Grenfell, New South Wales (lat 33° 55’S, long 147° 45’E). The transect was selected on the basis of (a) minimising the effects of non-soil factors (human interference, climate and relief) on vegetation and (b) the presence of various soil and vegetation types as indicated by previous mapping. ‘Soils’ were considered at three levels: soil landscapes (a broad mapping unit widely used in central western NSW), soil types (according to a range of classifications) and soil properties (depth, pH, etc.). ‘Vegetation’ was considered in three ways: vegetation type (in various classifications), density/floristic indices (density of woody species, abundance of native species, etc.) and presence/absence of individual species. Sites along the transect were grouped according to soil landscapes or soil types and compared to vegetation types or indices recorded at the sites. Various measures indicated low associations between vegetation types and soil landscapes or soil types. Except for infrequent occurrences of a soil type or landscape, any one soil type or landscape was commonly associated with a number of vegetation types and any one vegetation type was associated with a number of soil landscapes or soil types. However, significant associations between some vegetation indices, mainly density or numbers of woody species, and some soil landscapes and soil types were evident. Although many species were relatively ubiquitous, some groups of species that were restricted to one or two soil types were identified. Canonical Correspondence Analysis provided some suggestions as to which properties (e.g. texture) of these soils were associated with the presence of particular species

    Four rural cemeteries in central western NSW: Islands of Australiana in a European sea?

    Get PDF
    Vascular plants present in groundstoreys of variously–managed areas in four cemeteries in central western NSW – two on the Central Western Slopes (Garra and Toogong) and two on the Central Tablelands (Lyndhurst and Carcoar) – were recorded over periods of 6–10 years. It was hypothesised that (a) areas of the cemeteries with a history of nil or low disturbance would represent high quality remnant vegetation (i.e. contain a diversity of native species but few naturalised species), and (b) that clearing of woody vegetation, together with similar management (e.g. regular mowing) would result in homogenisation of the groundstoreys such that many species, native and naturalised, would be common to all sites. 344 species (176 native, 154 naturalised and 14 non–naturalised exotics) were recorded across the four cemeteries. Many native species that were rare in the surrounding agricultural lands were present in the cemeteries (enhancing their value as conservation areas) but no cemetery contained areas of groundstorey that would qualify as ‘pristine’. Across all management areas, the proportions of naturalised species in the native + naturalised floras of the cemeteries ranged from 46 to 55 %. Though never dominant, naturalised species also comprised high proportions (42 to 51 %) of the floras of the least disturbed (nil or infrequently mown) areas within each cemetery. Many (40 %) of the species recorded occurred at only one cemetery. This partly explained why the floras of similarly– managed parts of cemeteries on the Central Western Slopes were, contrary to expectations, markedly different to those on the Central Tablelands. However, within the same botanic subdivision, floras – particularly of naturalised species in regularly mown grasslands – were more similar (‘homogenised’) than those of nil or infrequently mown grasslands

    Assessing progress in protecting non-smokers from secondhand smoke

    Get PDF
    Objective To examine trends in population exposure to second-hand tobacco smoke (SHS) and consider two exposure metrics as appropriate targets for tobacco control policymakers. Design Comparison of adult non-smokers’ salivary cotinine data available from eleven Scottish Health Surveys between 1998 and 2016. Methods The proportions of non-smoking adults who had measurable levels of cotinine in their saliva were calculated for the eleven time points. The Geometric Mean (GM) concentrations of cotinine levels were calculated using Tobit regression. Changes in both parameters were assessed for the whole period and also for the years since implementation of smoke-free legislation in Scotland in 2006. Results Salivary cotinine expressed as a GM fell from 0.464 ng/ml (95% CI 0.444-0.486 ng/ml) in 1998 to 0.013 ng/ml (95% CI 0.009-0.020 ng/ml) in 2016: a reduction of 97.2%. The percentage of non-smoking adults who had no measurable cotinine in their saliva increased by nearly six-fold between 1998 (12.5% [95% CI 11.5%-13.6%]) and 2016 (81.6% [95% CI 78.6%-84.6%]). Reductions in population exposure to SHS have continued even after smoke-free legislation in 2006. Conclusions Scotland has witnessed a dramatic reduction in SHS exposure in the past two decades but there are still nearly one in five non-smoking adults who have measurable exposure to SHS on any given day. Tobacco control strategies globally should consider the use of both the proportion of non-smoking adults with undetectable salivary cotinine and the GM as targets to encourage policies that achieve a smoke-free future

    Pneumonia and exposure to household air pollution in children under the age of 5 years in rural Malawi findings from the Cooking And Pneumonia Study

    Get PDF
    Background Exposure to household air pollution is associated with an increased risk of pneumonia in children in low- and middle-income countries, however exposure-response data are limited and there are uncertainties around the extent to which biomass-fueled cookstoves can reduce these exposures. Research question What is the association between exposure to household air pollution and pneumonia in children under the age of 5 years in rural Malawi and what are the effects of a biomass-fueled cookstove intervention on personal exposure to household air pollution? Study design and methods We measured personal exposure to carbon monoxide (CO) [48 hours of continuous measurement and transcutaneous carboxyhemoglobin (COHb)] 6-monthly in children participating in a cluster-randomised controlled trial of a cleaner-burning biomass-fueled cookstove intervention to prevent pneumonia in children under the age of 5 years in rural Malawi – the Cooking And Pneumonia Study (CAPS). Exposure-response and multi-variable analyses were done. Results We recruited 1805 (928 intervention; 877 control) children (mean age 25.6 months, 50.6% female). We found no evidence of an association between exposure to CO (IRR=1.0 95% CI:0.967-1.014; p=0.53) or COHb (IRR=1.00 95% CI:0.993-1.003; p=0.41)) in children who experienced pneumonia versus those who did not. Median exposure to CO in the intervention and control groups was was 0.34 ppm (IQR 0.15-0.81) and 0.37 ppm (IQR 0.15-0.97), respectively. The group difference in means was 0.46 (95% CI:-0.95-0.012; p=0.06). Interpretation Exposure to CO in our population was low with no association seen between exposure to CO and pneumonia incidence and no effect of the CAPS intervention on these exposures. These findings suggest that CO may not be an appropriate measure of household air pollution exposure in settings like rural Malawi and that there is a need to develop ways to directly measure particulate matter exposures in young children instead

    A novel deep learning method for large-scale analysis of bone marrow adiposity using UK Biobank Dixon MRI data

    Get PDF
    BACKGROUND: Bone marrow adipose tissue (BMAT) represents &gt; 10% fat mass in healthy humans and can be measured by magnetic resonance imaging (MRI) as the bone marrow fat fraction (BMFF). Human MRI studies have identified several diseases associated with BMFF but have been relatively small scale. Population-scale studies therefore have huge potential to reveal BMAT's true clinical relevance. The UK Biobank (UKBB) is undertaking MRI of 100,000 participants, providing the ideal opportunity for such advances.OBJECTIVE: To establish deep learning for high-throughput multi-site BMFF analysis from UKBB MRI data.MATERIALS AND METHODS: We studied males and females aged 60-69. Bone marrow (BM) segmentation was automated using a new lightweight attention-based 3D U-Net convolutional neural network that improved segmentation of small structures from large volumetric data. Using manual segmentations from 61-64 subjects, the models were trained to segment four BM regions of interest: the spine (thoracic and lumbar vertebrae), femoral head, total hip and femoral diaphysis. Models were tested using a further 10-12 datasets per region and validated using datasets from 729 UKBB participants. BMFF was then quantified and pathophysiological characteristics assessed, including site- and sex-dependent differences and the relationships with age, BMI, bone mineral density, peripheral adiposity, and osteoporosis.RESULTS: Model accuracy matched or exceeded that for conventional U-Nets, yielding Dice scores of 91.2% (spine), 94.5% (femoral head), 91.2% (total hip) and 86.6% (femoral diaphysis). One case of severe scoliosis prevented segmentation of the spine, while one case of Non-Hodgkin Lymphoma prevented segmentation of the spine, femoral head and total hip because of T2 signal depletion; however, successful segmentation was not disrupted by any other pathophysiological variables. The resulting BMFF measurements confirmed expected relationships between BMFF and age, sex and bone density, and identified new site- and sex-specific characteristics.CONCLUSIONS: We have established a new deep learning method for accurate segmentation of small structures from large volumetric data, allowing high-throughput multi-site BMFF measurement in the UKBB. Our findings reveal new pathophysiological insights, highlighting the potential of BMFF as a novel clinical biomarker. Applying our method across the full UKBB cohort will help to reveal the impact of BMAT on human health and disease.</p

    Adverse prognosis associated with asymmetric myocardial thickening in aortic stenosis

    Get PDF
    Aims: Asymmetric wall thickening has been described in patients with aortic stenosis. However, it remains poorly characterized and its prognostic implications are unclear. We hypothesized this pattern of adaptation is associated with advanced remodelling, left ventricular decompenzation, and a poor prognosis. Methods and results: In a prospective observational cohort study, 166 patients with aortic stenosis (age 69, 69% males, mean aortic valve area 1.0 ± 0.4 cm2) and 37 age and sex-matched healthy volunteers underwent phenotypic characterization with comprehensive clinical, imaging, and biomarker evaluation. Asymmetric wall thickening on both echocardiography and cardiovascular magnetic resonance was defined as regional wall thickening ≥ 13 mm and > 1.5-fold the thickness of the opposing myocardial segment. Although no control subject had asymmetric wall thickening, it was observed in 26% (n = 43) of patients with aortic stenosis using magnetic resonance and 17% (n = 29) using echocardiography. Despite similar demographics, co-morbidities, valve narrowing, myocardial hypertrophy, and fibrosis, patients with asymmetric wall thickening had increased cardiac troponin I and brain natriuretic peptide concentrations (both P < 0.001). Over 28 [22, 33] months of follow-up, asymmetric wall thickening was an independent predictor of aortic valve replacement (AVR) or death whether detected by magnetic resonance [hazard ratio (HR) = 2.15; 95% confidence interval (CI) 1.29-3.59; P = 0.003] or echocardiography (HR = 1.79; 95% CI 1.08-3.69; P = 0.021). Conclusion: Asymmetric wall thickening is common in aortic stenosis and is associated with increased myocardial injury, left ventricular decompenzation, and adverse events. Its presence may help identify patients likely to proceed quickly towards AVR. Clinical Trial Registration: https://clinicaltrials.gov/show/NCT01755936: NCT01755936

    ISGylation drives basal breast tumour progression by promoting EGFR recycling and Akt signalling

    Get PDF
    ISG15 is an ubiquitin-like modifier that is associated with reduced survival rates in breast cancer patients. The mechanism by which ISG15 achieves this however remains elusive. We demonstrate that modification of Rab GDP-Dissociation Inhibitor Beta (GDI2) by ISG15 (ISGylation) alters endocytic recycling of the EGF receptor (EGFR) in non-interferon stimulated cells using CRISPR-knock out models for ISGylation. By regulating EGFR trafficking, ISGylation enhances EGFR recycling and sustains Akt-signalling. We further show that Akt signalling positively correlates with levels of ISG15 and its E2-ligase in basal breast cancer cohorts, confirming the link between ISGylation and Akt signalling in human tumours. Persistent and enhanced Akt activation explains the more aggressive tumour behaviour observed in human breast cancers. We show that ISGylation can act as a driver of tumour progression rather than merely being a bystander.</p
    corecore