16 research outputs found

    The Woody Guthrie Centennial Bibliography

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    This bibliography updates two extensive works designed to include comprehensively all significant works by and about Woody Guthrie. Richard A. Reuss published A Woody Guthrie Bibliography, 1912–1967 in 1968 and Jeffrey N. Gatten\u27s article “Woody Guthrie: A Bibliographic Update, 1968–1986” appeared in 1988. With this current article, researchers need only utilize these three bibliographies to identify all English-language items of relevance related to, or written by, Guthrie

    Chemical weathering and solute export by meltwater in a maritime Antarctic glacier basin

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    Solute yields, laboratory dissolution data and both chemical and isotopic markers of rock weathering reactions are used to characterise the biogeochemistry of glacial meltwaters draining a maritime Antarctic glacier. We find that delayed flowpaths through ice-marginal talus and moraine sediments are critical for the acquisition of solute from rock minerals because delayed flowpaths through subglacial sediments are absent beneath this small, cold-based glacier. Here the mechanisms of weathering are similar to those reported in subglacial environments, and include sub-oxic conditions in the early summer and increasingly oxic conditions thereafter. Up to 85% of the NO3 − and 65% of the SO4 2− are most likely produced by bacterially mediated reactions in these ice marginal sediments. However, reactive pyrite phases are sparse in the host rocks, limiting the export of Fe, SO4 2− and cations that may be removed by weathering once pyrite oxidation has taken place. This means that dissolution of Ca2+ and Na+ from carbonate and silicate minerals dominate, producing moderate cationic denudation yields from Tuva Glacier (163 Σ*meq+ m−2 a−1) compared to a global range of values (94–4,200 Σ*meq+ km−2 a−1). Overall, crustally derived cations represent 42% of the total cationic flux, the rest being accounted for by snowpack sources

    Chemical and isotopic switching within the subglacial environment of a high Arctic glacier.

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    Natural environmental isotopes of nitrate, sulphate and inorganic carbon are discussed in conjunction with major ion chemistry of subglacial runoff from a High Arctic glacier, Midre Lovénbreen, Svalbard. The chemical composition of meltwaters is observed to switch in accordance with subglacial hydrological evolution and redox status. Changing rapidly from reducing to oxidizing conditions, subglacial waters also depict that 15N/14N values show microbial denitrification is an active component of nutrient cycling beneath the glacier. 18O/16O ratios of sulphate are used to elucidate mechanisms of biological and abiological sulphide oxidation. Concentrations of bicarbonate appear to be governed largely by the degree of rock:water contact encountered in the subglacial system, rather than the switch in redox status, although the potential for microbiological activity to influence ambient bicarbonate concentrations is recognised. Glaciers are therefore highlighted as cryospheric ecosystems supporting microbial life which directly impacts upon the release of solute through biogeochemically mediated processes

    Benthic Dissolved Silicon and Iron Cycling at Glaciated Patagonian Fjord Heads.

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    Funder: University of South Florida; Id: http://dx.doi.org/10.13039/100008900Funder: Royal Society Wolfson Merit AwardGlacier meltwater supplies silicon (Si) and iron (Fe) sourced from weathered bedrock to downstream ecosystems. However, the extent to which these nutrients reach the ocean is regulated by the nature of the benthic cycling of dissolved Si and Fe within fjord systems, given the rapid deposition of reactive particulate fractions at fjord heads. Here, we examine the benthic cycling of the two nutrients at four Patagonian fjord heads through geochemical analyses of sediment pore waters, including Si and Fe isotopes (ή30Si and ή56Fe), and reaction-transport modeling for Si. A high diffusive flux of dissolved Fe from the fjord sediments (up to 0.02 mmol m-2 day-1) compared to open ocean sediments (typically 0.1 mmol m-2 day-1). High pore water ή30Si (up to +3.3‰) observed near the Fe(II)-Fe(III) redox boundary is likely associated with the removal of dissolved Si by Fe(III) mineral phases, which, together with high sedimentation rates, contribute to the low diffusive flux of Si at the sampled sites. Our results suggest that early diagenesis promotes the release of dissolved Fe, yet suppresses the release of dissolved Si at glaciated fjord heads, which has significant implications for understanding the downstream transport of these nutrients along fjord systems

    Do polypills lead to neglect of lifestyle risk factors? Findings from an individual participant data meta-analysis among 3140 patients at high risk of cardiovascular disease

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    Aim The aim of this study was to investigate whether polypill-based care for the prevention of cardiovascular disease (CVD) is associated with a change in lifestyle risk factors when compared with usual care, among patients with CVD or high calculated cardiovascular risk. Methods We conducted an individual participant data meta-analysis of three trials including patients from Australia, England, India, Ireland, the Netherlands and New Zealand that compared a strategy using a polypill containing aspirin, statin and antihypertensive therapy with usual care in patients with a prior CVD event or who were at high risk of their first event. Analyses investigated any differential effect on anthropometric measures and self-reported lifestyle behaviours. Results Among 3140 patients (75% male, mean age 62 years and 76% with a prior CVD event) there was no difference in lifestyle risk factors in those randomised to polypill-based care compared with usual care over a median of 15 months, either across all participants combined, or in a range of subgroups. Furthermore, narrow confidence intervals (CIs) excluded any major effect; for example differences between the groups in body mass index was -0.1 (95% CI -0.2 to 0.1) kg/m2, in weekly duration of moderate intensity physical activity was -2 (-26 to 23) minutes and the proportion of smokers was 16% vs 17% (RR 0.98, 0.84 to 1.15) at the end of trial. Discussion This analysis allays concern that polypill-based care may lead to neglect of lifestyle risk factors, at least among high-risk patients. Maximally effective preventive approaches should address lifestyle factors alongside pharmaceutical interventions, as recommended by major international guidelines

    Do polypills lead to neglect of lifestyle risk factors? Findings from an individual participant data meta-analysis among 3140 patients at high risk of cardiovascular disease

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    Aim The aim of this study was to investigate whether polypill-based care for the prevention of cardiovascular disease (CVD) is associated with a change in lifestyle risk factors when compared with usual care, among patients with CVD or high calculated cardiovascular risk. Methods We conducted an individual participant data meta-analysis of three trials including patients from Australia, England, India, Ireland, the Netherlands and New Zealand that compared a strategy using a polypill containing aspirin, statin and antihypertensive therapy with usual care in patients with a prior CVD event or who were at high risk of their first event. Analyses investigated any differential effect on anthropometric measures and self-reported lifestyle behaviours. Results Among 3140 patients (75% male, mean age 62 years and 76% with a prior CVD event) there was no difference in lifestyle risk factors in those randomised to polypill-based care compared with usual care over a median of 15 months, either across all participants combined, or in a range of subgroups. Furthermore, narrow confidence intervals (CIs) excluded any major effect; for example differences between the groups in body mass index was -0.1 (95% CI -0.2 to 0.1) kg/m2, in weekly duration of moderate intensity physical activity was -2 (-26 to 23) minutes and the proportion of smokers was 16% vs 17% (RR 0.98, 0.84 to 1.15) at the end of trial. Discussion This analysis allays concern that polypill-based care may lead to neglect of lifestyle risk factors, at least among high-risk patients. Maximally effective preventive approaches should address lifestyle factors alongside pharmaceutical interventions, as recommended by major international guidelines

    Effectiveness of fixed dose combination medication ('polypills') compared with usual care in patients with cardiovascular disease or at high risk : A prospective, individual patient data meta-analysis of 3140 patients in six countries

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    Aims To conduct a prospective, individual participant data (IPD) meta-analysis of randomised controlled trials comparing a polypill-based approach with usual care in high risk individuals. Methods and results Three trials comparing polypill-based care with usual care in individuals with CVD or high calculated cardiovascular risk contributed IPD. Primary outcomes were self-reported adherence to combination therapy (anti-platelet, statin and ≄ two blood pressure (BP) lowering agents), and difference in mean systolic BP (SBP) and LDL-cholesterol at 12 months. Analyses used random effects models. Among 3140 patients from Australia, England, India, Ireland, New Zealand and The Netherlands (75% male, mean age 62 years), median follow-up was 15 months. At baseline, 84%, 87% and 61% respectively were taking a statin, anti-platelet agent and at least two BP lowering agents. At 12 months, compared to usual care, participants in the polypill arm had higher adherence to combination therapy (80% vs. 50%, RR 1.58; 95% CI, 1.32 to 1.90; p <0.001), lower SBP (- 2.5 mmHg; 95% CI, - 4.5 to - 0.4; p = 0.02) and lower LDL-cholesterol (- 0.1 mmol/L; 95% CI, - 0.2 to 0.0; p = 0.04). Baseline treatment levels were a major effect modifier for adherence and SBP (p-homog <0.0001 and 0.02 respectively) with greatest improvements seen among those under-treated at baseline. Conclusions Polypill therapy significantly improved adherence, SBP and LDL-cholesterol in high risk patients compared with usual care, especially among those who were under-treated at baseline

    Reaching cardiovascular prevention guideline targets with a polypill-based approach : A meta-analysis of randomised clinical trials

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    Objective: The aim of this study was to determine the effect of polypill-based care on the achievement of 2016 European Society of Cardiology (ESC) guideline targets for blood pressure (BP), low-density lipoprotein (LDL) cholesterol and antiplatelet therapy. Methods: We conducted an individual participant data meta-analysis of three randomised clinical trials that compared a strategy using a polypill containing aspirin, statin and antihypertensive therapy with usual care in patients with a prior cardiovascular disease (CVD) event or who were at high risk of their first event. Overall, the trials included 3140 patients from Australia, England, India, Ireland, the Netherlands and New Zealand (75% male, mean age 62 years and 76% with a prior CVD event). The primary outcome for this study was the proportion of people achieving ESC guideline targets for BP, LDL and antiplatelet therapy. Results: Those randomised to polypill-based care were more likely than those receiving usual care to achieve recommended targets for BP (62% vs 58%, risk ratio (RR) 1.08, 95% CI 1.02 to 1.15), LDL (39% vs 34%, RR 1.13, 95% CI 1.02 to 1.25) and all three targets for BP, LDL and adherence to antiplatelet therapy (the latter only applicable to those with a prior CVD event) simultaneously (24% vs 19%, RR 1.27, 95% CI 1.10 to 1.47) at 12 months. There was no difference between groups in antiplatelet adherence (96% vs 96%, RR 1.00, 95% CI 0.98 to 1.01). There was heterogeneity by baseline treatment intensity such that treatment effects increased with the fewer the number of treatments being taken at baseline: for patients taking 3, 2 and 0-1 treatment modalities the RRs for reaching all three guideline goals simultaneously were 1.10 (95% CI 0.94 to 1.30, 22% vs 20%), 1.62 (95% CI 1.09 to 2.42, 27% vs 17%) and 3.07 (95% CI 1.77 to 5.33, 35% vs 11%), respectively. Conclusions: Polypill-based therapy significantly improved the achievement of all three ESC targets for BP, LDL and antiplatelet therapy compared with usual care, particularly among those undertreated at baseline

    Observational data and model output for sediment nutrient cycling at Patagonian fjords

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    Glacier meltwater supplies a significant amount of silicon (Si) and iron (Fe) sourced from weathered bedrock to downstream ecosystems. However, the extent to which these essential nutrients reach the ocean is regulated by the nature of the benthic cycling of dissolved Si and Fe within fjord systems, given the rapid deposition of reactive particulate fractions at fjord heads. The dataset is used to examine the benthic cycling of the two nutrients at Patagonian fjord heads through geochemical analyses of sediment pore waters and reaction-transport modeling for Si. The dataset contains: (i) pore water redox-sensitive nitrate (NO3-) and dissolved manganese (dMn) concentration data, nutrient dissolved silicon (DSi) and iron (dFe) concentration and isotope data (delta30 Si, delta56 Fe); (ii) mild alkaline leachable (Si-Alk) and acid leachable (Si-HCl) sediment silica content and isotope data; and (iii) reaction transport model output for the benthic cycling of Si. The pore water and sediment samples were collected from four sites: SJ (48.228o S, 73.502o W, 106 m depth), SH (47.679 S, 73.715 W, 203 m depth), SP (48.179 S, 73.347 W, 248 m depth) and SB (47.787 S, 73.610 W, 151 m depth) in the Baker-Martinez Fjord Complex on the research vessel Sur-Austral in February 2017. Funded by NERC-CONICYT grant NE/P003133/1-PII20150106
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