8 research outputs found

    A path to stable low-torque plasma operation in ITER with test blanket modules

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    New experiments in the low-torque ITER Q = 10 scenario on DIII-D demonstrate that n = 1 magnetic fields from a single row of ex-vessel control coils enable operation at ITER performance metrics in the presence of applied non-axisymmetric magnetic fields from a test blanket module (TBM) mock-up coil. With n = 1 compensation, operation below the ITER-equivalent injected torque is successful at three times the ITER equivalent toroidal magnetic field ripple for a pair of TBMs in one equatorial port, whereas the uncompensated TBM field leads to rotation collapse, loss of H-mode and plasma current disruption. In companion experiments at high plasma beta, where the n = 1 plasma response is enhanced, uncorrected TBM fields degrade energy confinement and the plasma angular momentum while increasing fast ion losses; however, disruptions are not routinely encountered owing to increased levels of injected neutral beam torque. In this regime, n = 1 field compensation leads to recovery of a dominant fraction of the TBM-induced plasma pressure and rotation degradation, and an 80% reduction in the heat load to the first wall. These results show that the n = 1 plasma response plays a dominant role in determining plasma stability, and that n = 1 field compensation alone not only recovers most of the impact on plasma performance of the TBM, but also protects the first wall from potentially damaging heat flux. Despite these benefits, plasma rotation braking from the TBM fields cannot be fully recovered using standard error field control. Given the uncertainty in extrapolation of these results to the ITER configuration, it is prudent to design the TBMs with as low a ferromagnetic mass as possible without jeopardizing the TBM mission

    Sequências de culturas em sistema de semeadura direta: I - produção de matéria seca e acúmulo de nutrientes

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    Em sistema de semeadura direta, os resíduos das culturas de entressafra são utilizados com as finalidades de proteger a superfície do solo dos agentes erosivos e de promover a ciclagem de nutrientes. O objetivo deste trabalho foi avaliar a produção de matéria seca e o acúmulo de nutrientes nos resíduos vegetais provenientes de diferentes sequências de culturas em semeadura direta. O experimento foi conduzido em Jaboticabal-SP (48° 18' W e 21° 15' S), em um Latossolo Vermelho eutrófico. O delineamento experimental foi em faixas, com três repetições. Os tratamentos foram constituídos pela combinação de três sequências de culturas de verão (rotação soja-milho e monoculturas de milho e de soja) com sete culturas de entressafra (milho, sorgo, girassol, crotalária, guandu, nabo forrageiro e milheto). O experimento iniciou-se em 2002, e o presente estudo refere-se aos anos agrícolas 2007/2008 e 2008/2009. Avaliaram-se as quantidades de matéria seca e o acúmulo de nutrientes pelas culturas. As culturas com colheita de grãos na entressafra (milho, sorgo e girassol) produziram resíduos com menor quantidade de nutrientes acumulados e em menor quantidade de matéria seca, quando comparadas às culturas com trituração no florescimento (crotalária, guandu, nabo forrageiro e milheto). Milheto e crotalária apresentaram as maiores produções de matéria seca e os maiores acúmulos de nutrientes. O milheto mostrou os maiores acúmulos de K e Mg, e a crotalária, maiores acúmulos de N e P. As gramíneas cultivadas na entressafra apresentaram maior desenvolvimento quando em sucessão ao cultivo de soja no verão anterior, com maior produção de matéria seca de milheto e, também, maior produtividade de grãos de milho e sorgo

    Adherence to antithrombotic therapy guidelines improves mortality among elderly patients with atrial fibrillation: insights from the REPOSI study

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    Background: Atrial fibrillation (AF) is associated with a substantial risk of thromboembolism and mortality, significantly reduced by oral anticoagulation. Adherence to guidelines may lower the risks for both all cause and cardiovascular (CV) deaths. Methods: Our objective was to evaluate if antithrombotic prophylaxis according to the 2012 European Society of Cardiology (ESC) guidelines is associated to a lower rate of adverse outcomes. Data were obtained from REPOSI; a prospective observational study enrolling inpatients aged 6565 years. Patients enrolled in 2012 and 2014 discharged with an AF diagnosis were analysed. Results: Among 2535 patients, 558 (22.0 %) were discharged with a diagnosis of AF. Based on ESC guidelines, 40.9 % of patients were on guideline-adherent thromboprophylaxis, 6.8 % were overtreated, and 52.3 % were undertreated. Logistic analysis showed that increasing age (p = 0.01), heart failure (p = 0.04), coronary artery disease (p = 0.013), peripheral arterial disease (p = 0.03) and concomitant cancer (p = 0.003) were associated with non-adherence to guidelines. Specifically, undertreatment was significantly associated with increasing age (p = 0.001) and cancer (p < 0.001), and inversely associated with HF (p = 0.023). AF patients who were guideline adherent had a lower rate of both all-cause death (p = 0.007) and CV death (p = 0.024) compared to those non-adherent. Kaplan\u2013Meier analysis showed that guideline-adherent patients had a lower cumulative risk for both all-cause (p = 0.002) and CV deaths (p = 0.011). On Cox regression analysis, guideline adherence was independently associated with a lower risk of all-cause and CV deaths (p = 0.019 and p = 0.006). Conclusions: Non-adherence to guidelines is highly prevalent among elderly AF patients, despite guideline-adherent treatment being independently associated with lower risk of all-cause and CV deaths. Efforts to improve guideline adherence would lead to better outcomes for elderly AF patients

    Scaling of the tokamak near the scrape-off layer H-mode power width and implications for ITER

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