16 research outputs found

    ECCD-induced sawtooth crashes at W7-X

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    The optimised superconducting stellarator W7-X generates its rotational transform by means of external coils, therefore no toroidal current is necessary for plasma confinement. Electron cyclotron current drive experiments were conducted for strikeline control and safe divertor operation. During current drive experiments periodic and repetitive crashes of the central electron temperature, similar to sawtooth crashes in tokamaks, were detected. Measurements from soft x-ray tomography and electron cyclotron emission show that the crashes are preceded by weak oscillating precursors and a displacement of the plasma core, consistent with a (m, n)=(1, 1) mode. The displacement occurs within 100μs, followed by expulsion and redistribution of the core into the external part of the plasma. Two types of crashes, with different frequencies and amplitudes are detected in the experimental program. For these non-stationary parameters a strong dependence on the toroidal current is found. A 1-D heuristic model for current diffusion is proposed as a first step to explain the characteristic crash time. Initial results show that the modelled current diffusion timescale is consistent with the initial crash frequency and that the toroidal current rise shifts the position where the instability is triggered, resulting in larger crash amplitudes

    TRY plant trait database – enhanced coverage and open access

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    Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

    Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

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    We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens of seconds. Pellet fueling allows for plasma phases with reduced ion-temperature-gradient turbulence, and during such phases, the overall confinement is so good (energy confinement times often exceeding 200 ms) that the attained density and temperature profiles would not have been possible in less optimized devices, since they would have had neoclassical transport losses exceeding the heating applied in W7-X. This provides proof that the reduction of neoclassical transport through magnetic field optimization is successful. W7-X plasmas generally show good impurity screening and high plasma purity, but there is evidence of longer impurity confinement times during turbulence-suppressed phases.EC/H2020/633053/EU/Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium/ EUROfusio

    Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

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    Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

    Overview of W7-X ECRH Results

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    In its second operation phase (OP1.2a) W7-X was equipped with full 3d island divertor and an upgraded ECRH-system of 10 gyrotrons with a total port through power of 7 MW. The combination of pellet fueling and high density ECRH enabled to explore density above 1 1020 m-3. In particular with the O2-polarisation combined with a multi-pass reflector tile system a density of up to 1.4 1020 m-3 was achieved. At slightly lower densities high core beta values and record values of the fusion tripple product of 0.66 1020 m-3 keVs for stellarators were reached. In addition routine plasma start-up and ECRH wall conditioning were performed. The island divertor enables to demonstrate the intrinsic steady state capabilities of W7-X, where stationary discharges of up to 30s were demonstrated being only limited by the heat capacity of the uncooled divertor. With the flexible ECRH launch system current density profile variations were used for MHD stability investigations. Here by fine-tuning of the ECCD profile different MHD activity could be triggered

    Overview of W7-X ECRH Results

    Get PDF
    In its second operation phase (OP1.2a) W7-X was equipped with full 3d island divertor and an upgraded ECRH-system of 10 gyrotrons with a total port through power of 7 MW. The combination of pellet fueling and high density ECRH enabled to explore density above 1 1020 m-3. In particular with the O2-polarisation combined with a multi-pass reflector tile system a density of up to 1.4 1020 m-3 was achieved. At slightly lower densities high core beta values and record values of the fusion tripple product of 0.66 1020 m-3 keVs for stellarators were reached. In addition routine plasma start-up and ECRH wall conditioning were performed. The island divertor enables to demonstrate the intrinsic steady state capabilities of W7-X, where stationary discharges of up to 30s were demonstrated being only limited by the heat capacity of the uncooled divertor. With the flexible ECRH launch system current density profile variations were used for MHD stability investigations. Here by fine-tuning of the ECCD profile different MHD activity could be triggered

    Efeitos cardiorrespiratórios do butorfanol em cães pré-tratados ou não pela levomepromazina Cardiopulmonary effects of butorphanol in dogs treated with levomepromazine

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    Objetivou-se com este experimento avaliar os efeitos do butorfanol precedido ou não pela levomepromazina sobre a freqüência cardíaca (FC), as pressões arteriais sistólica, diastólica e média (PAS, PAD e PAM, respectivamente), a freqüência respiratória (f), a concentração de dióxido de carbono ao final da expiração (ETCO2), a saturação da oxihemoglobina (SpO2), o volume corrente (VC) e o volume minuto (VM), em cães. Para tal, foram empregados vinte animais adultos, clinicamente saudáveis, distribuídos igualmente em dois grupos (GC e GL). Ao GC administrou-se solução salina a 0,9% (Controle), no volume de 0,2mL kg-1, pela via intravenosa (IV). Decorridos 15 minutos, administrou-se butorfanol na dose de 0,3mg kg-1 pela mesma via. Aos animais do GL foi adotada a mesma metodologia, porém substituindo-se a solução salina pela levomepromazina na dose de 1mg kg-1. As medidas das variáveis cardiorrespiratórias iniciaram-se imediatamente antes da aplicação dos fármacos (M1). Novas mensurações foram realizadas 15 minutos após a administração da solução salina a 0,9% ou levomepromazina (M2) e 10 minutos após a administração de butorfanol (M3). As demais colheitas foram realizadas a intervalos de 10 minutos, durante 30 minutos (M4, M5 e M6, respectivamente). Os dados numéricos colhidos foram submetidos à Análise de Variância (ANOVA), seguida pelo teste de Tukey (p<0,05) para as comparações das médias. O emprego do butorfanol promoveu diminuição significativa das freqüências cardíaca e respiratória e do volume minuto no grupo previamente tratado pela levomepromazina; entretanto, essas alterações foram discretas, não comprometendo os demais parâmetros circulatórios e respiratórios.<br>This work was aimed at evaluating the effects of the butorphanol in dogs preceded or not buy levomepromazine on heart rate (HR), systolic, diastolic and mean arterial pressure (SAP, DAP and MAP, respectively), respiratory rate (RR), end tidal CO2 (ETCO2), oxyhemoglobin saturation (SpO2), minute volume (MV) and tidal volume (TV). Twenty adult animals, clinically health were randomly distributed in two groups with ten animals each one (CG and LG). The first one received intravenous administration (IV) of 0.2mL kg-1 of saline solution at 0.9% (control). After 15 minutes, 0.3mg kg-1 of butorphanol was administrated by the same way. The same methodology was adopted to the GL animals, however, the saline solution at 0.9% was substituted to 1mg kg-1 of levomepromazine. The cardiorespiratory parameters were measured before the administration of the drugs (M1). New measurements were carried 15 minutes after saline or levomepromazine administration (M2), and 10 minutes after butorphanol administration (M3). The next M4, M5 and M6 were carried out through at intervals of 10 minutes during 30 minutes. The numeric data were submitted to the Analysis of Variance (ANOVA) followed by Tukey test (p<0.05) for the comparisons of the averages. The butorfanol promoted significative decreasing on cardiac and respiratory rate and reduction on minute volume after administration of levomepromazine. However these changes were discreet and did not produce depression on other circulatory and breathing parameters
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