188 research outputs found

    Simulating Australian soil organic carbon sequestration

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    National initiatives to mitigate and adopt to climate change imply the need for enhancing carbon (C) sequestration in soils. Soil process models often render a C baseline hardly representative and its C sequestration potential questionable when initial soil C pools are not accounted. Here we use the soil process model Roth C to simulate site-specific soil C across 4431 sites in Australia. After matching the modelled and measured C pools at initial equilibrium, the model predicted C sequestration potentials in soils, coherent to changes among the pools, in response to soil inputs that represent soil and residue management. We show that the extent of C sequestration is constrained by C composition that is further influenced by climate and land use. Our results highlight the importance of improving and optimising climate change mitigation and adaptation based on soil C composition

    Continental soil drivers of ammonium and nitrate in Australia

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    Soil N is an essential element for plant growth, but its mineral forms are subject to loss from the environment by leaching and gaseous emissions. Despite its importance for the soil-plant system, factors controlling soil mineral N contents over large spatial scales are not well understood. We used and contents (0–30 cm depth) from 469 sites across Australia and determined soil controls on their regional variation. Soil mineral N varied regionally but depended on the different land uses. In the agricultural region of Australia, tended to be similar (median 4.0 vs. 3.5 mg N kg−1) and was significantly enriched (3.0 vs. 1.0 mg N kg−1), compared to the non-agricultural region. The importance of soil controls on mineral N in the agricultural region, identified by the model trees algorithm Cubist, showed that was affected by total N, cation exchange capacity (CEC) and pH. In the non-agricultural region, was affected not only by CEC and pH, but also by organic C and total P. In each of the regions, was primarily affected by CEC, with more complex biophysical controls. In both regions, correlations between mineral N and soil C : N : P stoichiometry suggest that more was found in P-depleted soil relative to total C and total N. However, our results showed that only in the non-agricultural region was sensitive to the state of C and its interaction with N and P. The models helped to explain 36 %–68 % of regional variation in mineral N. Although soil controls on high N contents were highly uncertain, we found that region-specific interactions of soil properties control mineral N contents. It is therefore essential to understand how they alter soil mechanisms and N cycling at large scales

    Continental-Scale Soil Organic Carbon Composition and Vulnerability Regulated by Regional Soil and Environmental Controls

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    Processes that control soil organic carbon (C) composition and dynamics over large scales are not well understood. Thus, our understanding of C cycling is incomplete, making it difficult to predict C gains and losses due to changes in climate, land use and management. In this paper, we show that controls on the composition of organic C, the particulate, humus (or mineral associated) and resistant fractions, and the potential vulnerability of C to decomposition across Australia are distinct, scale-dependent and variable

    Moving toward Universal Coverage of Health Insurance in Vietnam: Barriers, Facilitating Factors, and Lessons from Korea

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    Vietnam has pursued universal health insurance coverage for two decades but has yet to fully achieve this goal. This paper investigates the barriers to achieve universal coverage and examines the validity of facilitating factors to shorten the transitional period in Vietnam. A comparative study of facilitating factors toward universal coverage of Vietnam and Korea reveals significant internal forces for Vietnam to further develop the National Health Insurance Program. Korea in 1977 and Vietnam in 2009 have common characteristics to be favorable of achieving universal coverage with similarities of level of income, highly qualified administrative ability, tradition of solidarity, and strong political leadership although there are differences in distribution of population and structure of the economy. From a comparative perspective, Vietnam can consider the experience of Korea in implementing the mandatory enrollment approach, household unit of eligibility, design of contribution and benefit scheme, and resource allocation to health insurance for sustainable government subsidy to achieve and sustain the universal coverage of health insurance.OAIID:oai:osos.snu.ac.kr:snu2014-01/102/0000034222/1SEQ:1PERF_CD:SNU2014-01EVAL_ITEM_CD:102USER_ID:0000034222ADJUST_YN:NEMP_ID:A079471DEPT_CD:801CITE_RATE:1.249DEPT_NM:의학과SCOPUS_YN:YCONFIRM:

    Deep learning segmentation of coronary calcified plaque from intravascular optical coherence tomography (IVOCT) images with application to finite element modeling of stent deployment

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    Because coronary artery calcified plaques can hinder or eliminate stent deployment, interventional cardiologists need a better way to plan interventions, which might include one of the many methods for calcification modification (e.g., atherectomy). We are imaging calcifications with intravascular optical coherence tomography (IVOCT), which is the lone intravascular imaging technique with the ability to image the extent of a calcification, and using results to build vessel-specific finite element models for stent deployment. We applied methods to a large set of image data (\u3e45 lesions and \u3e 2,600 image frames) of calcified plaques, manually segmented by experts into calcified, lumen and “other” tissue classes. In optimization experiments, we evaluated anatomical (x, y) versus acquisition (r,θ) views, augmentation methods, and classification noise cleaning. Noisy semantic segmentations are cleaned by applying a conditional random field (CRF). We achieve an accuracy of 0.85 ± 0.04, 0.99 ± 0.01, and 0.97 ± 0.01, and F-score of 0.88 ± 0.07, 0.97 ± 0.01, and 0.91 ± 0.04 for calcified, lumen, and other tissues classes respectively across all folds following CRF noise cleaning. As a proof of concept, we applied our methods to cadaver heart experiments on highly calcified plaques. Following limited manual correction, we used our calcification segmentations to create a lesion-specific finite element model (FEM) and used it to predict direct stenting deployment at multiple pressure steps. FEM modeling of stent deployment captured many features found in the actual stent deployment (e.g., lumen shape, lumen area, and location and number of apposed stent struts)

    Effects of municipal smoke-free ordinances on secondhand smoke exposure in the Republic of Korea

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    ObjectiveTo reduce premature deaths due to secondhand smoke (SHS) exposure among non-smokers, the Republic of Korea (ROK) adopted changes to the National Health Promotion Act, which allowed local governments to enact municipal ordinances to strengthen their authority to designate smoke-free areas and levy penalty fines. In this study, we examined national trends in SHS exposure after the introduction of these municipal ordinances at the city level in 2010.MethodsWe used interrupted time series analysis to assess whether the trends of SHS exposure in the workplace and at home, and the primary cigarette smoking rate changed following the policy adjustment in the national legislation in ROK. Population-standardized data for selected variables were retrieved from a nationally representative survey dataset and used to study the policy action’s effectiveness.ResultsFollowing the change in the legislation, SHS exposure in the workplace reversed course from an increasing (18% per year) trend prior to the introduction of these smoke-free ordinances to a decreasing (−10% per year) trend after adoption and enforcement of these laws (β2 = 0.18, p-value = 0.07; β3 = −0.10, p-value = 0.02). SHS exposure at home (β2 = 0.10, p-value = 0.09; β3 = −0.03, p-value = 0.14) and the primary cigarette smoking rate (β2 = 0.03, p-value = 0.10; β3 = 0.008, p-value = 0.15) showed no significant changes in the sampled period. Although analyses stratified by sex showed that the allowance of municipal ordinances resulted in reduced SHS exposure in the workplace for both males and females, they did not affect the primary cigarette smoking rate as much, especially among females.ConclusionStrengthening the role of local governments by giving them the authority to enact and enforce penalties on SHS exposure violation helped ROK to reduce SHS exposure in the workplace. However, smoking behaviors and related activities seemed to shift to less restrictive areas such as on the streets and in apartment hallways, negating some of the effects due to these ordinances. Future studies should investigate how smoke-free policies beyond public places can further reduce the SHS exposure in ROK

    Two-Year Changes in Diabetic Kidney Disease Phenotype and the Risk of Heart Failure: A Nationwide Population-Based Study in Korea

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    Background Diabetic kidney disease (DKD) is a risk factor for hospitalization for heart failure (HHF). DKD could be classified into four phenotypes by estimated glomerular filtration rate (eGFR, normal vs. low) and proteinuria (PU, negative vs. positive). Also, the phenotype often changes dynamically. This study examined HHF risk according to the DKD phenotype changes across 2-year assessments. Methods The study included 1,343,116 patients with type 2 diabetes mellitus (T2DM) from the Korean National Health Insurance Service database after excluding a very high-risk phenotype (eGFR <30 mL/min/1.73 m2) at baseline, who underwent two cycles of medical checkups between 2009 and 2014. From the baseline and 2-year eGFR and PU results, participants were divided into 10 DKD phenotypic change categories. Results During an average of 6.5 years of follow-up, 7,874 subjects developed HHF. The cumulative incidence of HHF from index date was highest in the eGFRlowPU– phenotype, followed by eGFRnorPU+ and eGFRnorPU–. Changes in DKD phenotype differently affect HHF risk. When the persistent eGFRnorPU– category was the reference, hazard ratios for HHF were 3.10 (95% confidence interval [CI], 2.73 to 3.52) in persistent eGFRnorPU+ and 1.86 (95% CI, 1.73 to 1.99) in persistent eGFRlowPU–. Among altered phenotypes, the category converted to eGFRlowPU+ showed the highest risk. In the normal eGFR category at the second examination, those who converted from PU– to PU+ showed a higher risk of HHF than those who converted from PU+ to PU–. Conclusion Changes in DKD phenotype, particularly with the presence of PU, are more likely to reflect the risk of HHF, compared with DKD phenotype based on a single time point in patients with T2DM
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