ORCID Profile
0000-0001-9445-0181
Current Organisations
Saolta Hospital Group
,
University of Galway
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Publisher: Elsevier BV
Date: 11-2016
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.SCITOTENV.2015.05.003
Abstract: Information on sediment sources in river catchments is required for effective sediment control strategies, to understand sediment, nutrient and pollutant transport, and for developing soil erosion management plans. Sediment fingerprinting procedures are employed to quantify sediment source contributions and have become a widely used tool. As fingerprinting procedures are naturally variable and locally dependant, there are different applications of the procedure. Here, the auto-evaluation of different fingerprinting procedures using virtual s le mixtures is proposed to support the selection of the fingerprinting procedure with the best capacity for source discrimination and apportionment. Surface s les from four land uses from a Central Spanish Pyrenean catchment were used i) as sources to generate the virtual s le mixtures and ii) to characterise the sources for the fingerprinting procedures. The auto-evaluation approach involved comparing fingerprinting procedures based on four optimum composite fingerprints selected by three statistical tests, three source characterisations (mean, median and corrected mean) and two types of objective functions for the mixing model. A total of 24 fingerprinting procedures were assessed by this new approach which were solved by Monte Carlo simulations and compared using the root mean squared error (RMSE) between known and assessed source ascriptions for the virtual s le mixtures. It was found that the source ascriptions with the highest accuracy were achieved using the corrected mean source characterisations for the composite fingerprints selected by the Kruskal Wallis H-test and principal components analysis. Based on the RMSE results, high goodness of fit (GOF) values were not always indicative of accurate source apportionment results, and care should be taken when using GOF to assess mixing model performance. The proposed approach to test different fingerprinting procedures using virtual s le mixtures provides an enhanced basis for selecting procedures that can deliver optimum source discrimination and apportionment.
Publisher: Springer Science and Business Media LLC
Date: 16-01-2014
DOI: 10.1038/SREP03714
Publisher: Elsevier BV
Date: 10-2018
DOI: 10.1016/J.SCITOTENV.2018.04.394
Abstract: Soil erosion by water is critical for soil, lake and reservoir degradation in the mid-hills of Nepal. Identification of the nature and relative contribution of sediment sources in rivers is important to mitigate water erosion within catchments and siltation problems in lakes and reservoirs. We estimated the relative contribution of land uses (i.e. sources) to suspended and streambed sediments in the Chitlang catchment using stable carbon isotope signature (δ
Publisher: S. Karger AG
Date: 2021
DOI: 10.1159/000515239
Abstract: b i Background: /i /b Previous studies reported an association of renal impairment with stroke, but there are uncertainties underpinning this association. b i Aims: /i /b We explored if the association is explained by shared risk factors or is independent and whether there are regional or stroke subtype variations. b i Methods: /i /b INTERSTROKE is a case-control study and the largest international study of risk factors for first acute stroke, completed in 27 countries. We included in iduals with available serum creatinine values and calculated estimated glomerular filtration rate (eGFR). Renal impairment was defined as eGFR & #x3c mL/min/1.73 m sup /sup . Multivariable conditional logistic regression was used to determine the association of renal function with stroke. b i Results: /i /b Of 21,127 participants, 41.0% were female, the mean age was 62.3 ± 13.4 years, and the mean eGFR was 79.9 ± 23.5 mL/min/1.73 m sup /sup . The prevalence of renal impairment was higher in cases (22.9% vs. 17.7%, i /i & #x3c 0.001) and differed by region ( i /i & #x3c 0.001). After adjustment, lower eGFR was associated with increased odds of stroke. Renal impairment was associated with increased odds of all stroke (OR 1.35 95% CI: 1.24–1.47), with higher odds for intracerebral hemorrhage (OR 1.60 95% CI: 1.35–1.89) than ischemic stroke (OR 1.29 95% CI: 1.17–1.42) ( i /i sub interaction /sub 0.12). The largest magnitudes of association were seen in younger participants and those living in Africa, South Asia, or South America ( i /i sub interaction /sub & #x3c 0.001 for all stroke). Renal impairment was also associated with poorer clinical outcome (RRR 2.97 95% CI: 2.50–3.54 for death within 1 month). b i Conclusion: /i /b Renal impairment is an important risk factor for stroke, particularly in younger patients, and is associated with more severe stroke and worse outcomes.
Publisher: Wiley
Date: 13-09-2019
DOI: 10.1002/HYP.13550
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 08-08-2015
Publisher: Elsevier BV
Date: 11-2016
Publisher: Wiley
Date: 26-09-2012
DOI: 10.1002/HYP.9537
Publisher: SAGE Publications
Date: 11-04-2016
Abstract: Recent evidence supports that most non-lacunar cryptogenic strokes are embolic. Accordingly, these strokes have been designated as embolic strokes of undetermined source (ESUS). We undertook an international survey to characterize the frequency and clinical features of ESUS patients across global regions. Consecutive patients hospitalized for ischemic stroke were retrospectively surveyed from 19 stroke research centers in 19 different countries to collect patients meeting criteria for ESUS. Of 2144 patients with recent ischemic stroke, 351 (16%, 95% CI 15% to 18%) met ESUS criteria, similar across global regions (range 16% to 21%), and an additional 308 (14%) patients had incomplete evaluation required for ESUS diagnosis. The mean age of ESUS patients (62 years SD = 15) was significantly lower than the 1793 non-ESUS ischemic stroke patients (68 years, p ≤ 0.001). Excluding patients with atrial fibrillation ( n = 590, mean age = 75 years), the mean age of the remaining 1203 non-ESUS ischemic stroke patients was 64 years ( p = 0.02 vs. ESUS patients). Among ESUS patients, hypertension, diabetes, and prior stroke were present in 64%, 25%, and 17%, respectively. Median NIHSS score was 4 (interquartile range 2–8). At discharge, 90% of ESUS patients received antiplatelet therapy and 7% received anticoagulation. This cross-sectional global s le of patients with recent ischemic stroke shows that one-sixth met criteria for ESUS, with additional ESUS patients likely among those with incomplete diagnostic investigation. ESUS patients were relatively young with mild strokes. Antiplatelet therapy was the standard antithrombotic therapy for secondary stroke prevention in all global regions.
Publisher: Oxford University Press (OUP)
Date: 12-2021
DOI: 10.1093/EURHEARTJ/EHAB738
Abstract: In INTERSTROKE, we explored the association of anger or emotional upset and heavy physical exertion with acute stroke, to determine the importance of triggers in a large, international population. INTERSTROKE was a case–control study of first stroke in 32 countries. Using 13 462 cases of acute stroke we adopted a case-crossover approach to determine whether a trigger within 1 hour of symptom onset (case period), vs. the same time on the previous day (control period), was associated with acute stroke. A total of 9.2% (n = 1233) were angry or emotional upset and 5.3% (n = 708) engaged in heavy physical exertion during the case period. Anger or emotional upset in the case period was associated with increased odds of all stroke [odds ratio (OR) 1.37, 99% confidence interval (CI), 1.15–1.64], ischaemic stroke (OR 1.22, 99% CI, 1.00–1.49), and intracerebral haemorrhage (ICH) (OR 2.05, 99% CI 1.40–2.99). Heavy physical exertion in the case period was associated with increased odds of ICH (OR 1.62, 99% CI 1.03–2.55) but not with all stroke or ischaemic stroke. There was no modifying effect by region, prior cardiovascular disease, risk factors, cardiovascular medications, time, or day of symptom onset. Compared with exposure to neither trigger during the control period, the odds of stroke associated with exposure to both triggers were not additive. Acute anger or emotional upset was associated with the onset of all stroke, ischaemic stroke, and ICH, while acute heavy physical exertion was associated with ICH only.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-01-2023
DOI: 10.1212/WNL.0000000000201388
Abstract: There is uncertainty about the association between alcohol consumption and stroke, particularly for low-moderate intake. We explored these associations in a large international study. INTERSTROKE, a case-control study, is the largest international study of risk factors for acute stroke. Alcohol consumption was self-reported and categorized by drinks/week as low (1–7), moderate (7–14 for females and 7–21 for males), or high ( for females and for males). Heavy episodic drinking (HED) was defined as drinks on ≥1 day per month. Multivariable conditional logistic regression was used to determine associations. We included 12,913 cases and 12,935 controls 25.0% (n = 6,449) were current drinkers, 16.7% (n = 4,318) former drinkers, and 58.3% (n = 15,076) never drinkers. Current drinkers were younger, male, smokers, active, and with higher-paid occupations. Current drinking was associated with all stroke (OR 1.14 95% CI 1.04–1.26) and intracerebral hemorrhage (ICH) (OR 1.50, 95% CI 1.21–1.84) but not ischemic stroke (OR 1.06 95% CI 0.95–1.19). HED pattern was associated with all stroke (OR 1.39 95% CI 1.21–1.59), ischemic stroke (OR 1.29 95% CI 1.10–1.51), and ICH (OR 1.76 95% CI 1.31–2.36). High level of alcohol intake was consistently associated with all stroke, ischemic stroke, and ICH. Moderate intake was associated with all stroke and ICH but not ischemic stroke. Low alcohol intake was not associated with stroke overall, but there were regional differences low intake was associated with reduced odds of stroke in Western Europe/North America (OR 0.66 95% CI 0.45–0.96) and increased odds in India (OR 2.18 95% CI 1.42–3.36) (p-interaction 0.037). Wine consumption was associated with reduced odds of all stroke and ischemic stroke but not ICH. The magnitudes of association were greatest in those without hypertension and current smokers. High and moderate intake were associated with increased odds of stroke, whereas low intake was not associated with stroke. However, there were important regional variations, which may relate to differences in population characteristics of alcohol consumers, types or patterns of consumption.
Publisher: IOP Publishing
Date: 03-12-2018
Publisher: Springer Science and Business Media LLC
Date: 30-08-2018
DOI: 10.1038/S41598-018-30905-9
Abstract: Increasing complexity in human-environment interactions at multiple watershed scales presents major challenges to sediment source apportionment data acquisition and analysis. Herein, we present a step-change in the application of Bayesian mixing models: Deconvolutional-MixSIAR (D-MIXSIAR) to underpin sustainable management of soil and sediment. This new mixing model approach allows users to directly account for the ‘structural hierarchy’ of a river basin in terms of sub-watershed distribution. It works by deconvoluting apportionment data derived for multiple nodes along the stream-river network where sources are stratified by sub-watershed. Source and mixture s les were collected from two watersheds that represented (i) a longitudinal mixed agricultural watershed in the south west of England which had a distinct upper and lower zone related to topography and (ii) a distributed mixed agricultural and forested watershed in the mid-hills of Nepal with two distinct sub-watersheds. In the former, geochemical fingerprints were based upon weathering profiles and anthropogenic soil amendments. In the latter compound-specific stable isotope markers based on soil vegetation cover were applied. Mixing model posterior distributions of proportional sediment source contributions differed when sources were pooled across the watersheds (pooled-MixSIAR) compared to those where source terms were stratified by sub-watershed and the outputs deconvoluted (D-MixSIAR). In the first ex le, the stratified source data and the deconvolutional approach provided greater distinction between pasture and cultivated topsoil source signatures resulting in a different posterior distribution to non-deconvolutional model (conventional approaches over-estimated the contribution of cultivated land to downstream sediment by 2 to 5 times). In the second ex le, the deconvolutional model elucidated a large input of sediment delivered from a small tributary resulting in differences in the reported contribution of a discrete mixed forest source. Overall D-MixSIAR model posterior distributions had lower (by ca 25–50%) uncertainty and quicker model run times. In both cases, the structured, deconvoluted output cohered more closely with field observations and local knowledge underpinning the need for closer attention to hierarchy in source and mixture terms in river basin source apportionment. Soil erosion and siltation challenge the energy-food-water-environment nexus. This new tool for source apportionment offers wider application across complex environmental systems affected by natural and human-induced change and the lessons learned are relevant to source apportionment applications in other disciplines.
Publisher: Springer Science and Business Media LLC
Date: 15-12-2020
DOI: 10.1038/S41597-020-00774-X
Abstract: Radiocesium released from the Fukushima Daiichi nuclear power plant (FDNPP) and deposited in the terrestrial environment has been transported to the sea through rivers. To study the long-term effect of riverine transport on the remediation process near the FDNPP, a monitoring project was initiated by the University of Tsukuba. It was commissioned by the Ministry of Education, Culture, Sports, Science, and Technology, and the Nuclear Regulatory Commission in June 2011, and was taken over by the Fukushima Prefectural Centre for Environmental Creation from April 2015. The activity concentration and monthly flux of radiocesium in a suspended form were measured in the project. This provides valuable measurement data to evaluate the impact of the accidentally released radiocesium on residents and the marine environment. It can also be used as verification data in the development and testing of numerical models to predict future impacts.
Publisher: Elsevier BV
Date: 06-2017
Publisher: Wiley
Date: 20-05-2014
DOI: 10.1002/ESP.3589
No related grants have been discovered for Michelle Canavan.