99 research outputs found
Demonstration of reduced neoclassical energy transport in Wendelstein 7-X
Research on magnetic confinement of high-temperature plasmas has the ultimate goal of harnessing nuclear fusion for the production of electricity. Although the tokamak(1) is the leading toroidal magnetic-confinement concept, it is not without shortcomings and the fusion community has therefore also pursued alternative concepts such as the stellarator. Unlike axisymmetric tokamaks, stellarators possess a three-dimensional (3D) magnetic field geometry. The availability of this additional dimension opens up an extensive configuration space for computational optimization of both the field geometry itself and the current-carrying coils that produce it. Such an optimization was undertaken in designing Wendelstein 7-X (W7-X)(2), a large helical-axis advanced stellarator (HELIAS), which began operation in 2015 at Greifswald, Germany. A major drawback of 3D magnetic field geometry, however, is that it introduces a strong temperature dependence into the stellarator's non-turbulent 'neoclassical' energy transport. Indeed, such energy losses will become prohibitive in high-temperature reactor plasmas unless a strong reduction of the geometrical factor associated with this transport can be achieved; such a reduction was therefore a principal goal of the design of W7-X. In spite of the modest heating power currently available, W7-X has already been able to achieve high-temperature plasma conditions during its 2017 and 2018 experimental campaigns, producing record values of the fusion triple product for such stellarator plasmas(3,4). The triple product of plasma density, ion temperature and energy confinement time is used in fusion research as a figure of merit, as it must attain a certain threshold value before net-energy-producing operation of a reactor becomes possible(1,5). Here we demonstrate that such record values provide evidence for reduced neoclassical energy transport in W7-X, as the plasma profiles that produced these results could not have been obtained in stellarators lacking a comparably high level of neoclassical optimization.Previously documented record values of the fusion triple product in the stellarator Wendelstein 7-X are shown to be evidence for reduced neoclassical energy transport in this optimized device
First proton-proton collisions at the LHC as observed with the ALICE detector: measurement of the charged-particle pseudorapidity density at root s=900 GeV
On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), two counter-rotating proton bunches were circulated for the first time concurrently in the machine, at the LHC injection energy of 450 GeV per beam. Although the proton intensity was very low, with only one pilot bunch per beam, and no systematic attempt was made to optimize the collision optics, all LHC experiments reported a number of collision candidates. In the ALICE experiment, the collision region was centred very well in both the longitudinal and transverse directions and 284 events were recorded in coincidence with the two passing proton bunches. The events were immediately reconstructed and analyzed both online and offline. We have used these events to measure the pseudorapidity density of charged primary particles in the central region. In the range vertical bar eta vertical bar S collider. They also illustrate the excellent functioning and rapid progress of the LHC accelerator, and of both the hardware and software of the ALICE experiment, in this early start-up phase
Comparison of Gas Exchange and Bioassay Determinations of the Ammonia Compensation Point in Luzula sylvatica
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Retest variability and patient reliability indices of quantitative fundus autofluorescence in age-related macular degeneration: a MACUSTAR study report
This study aimed to determine the retest variability of quantitative fundus autofluorescence (QAF) in patients with and without age-related macular degeneration (AMD) and evaluate the predictive value of patient reliability indices on retest reliability. A total of 132 eyes from 68 patients were examined, including healthy individuals and those with various stages of AMD. Duplicate QAF imaging was conducted at baseline and 2 weeks later across six study sites. Intraclass correlation (ICC) analysis was used to evaluate the consistency of imaging, and mean opinion scores (MOS) of image quality were generated by two researchers. The contribution of MOS and other factors to retest variation was assessed using mixed-effect linear models. Additionally, a Random Forest Regressor was trained to evaluate the extent to which manual image grading of image quality could be replaced by automated assessment (inferred MOS). The results showed that ICC values were high for all QAF images, with slightly lower values in AMD-affected eyes. The average inter-day ICC was found to be 0.77 for QAF segments within the QAF8 ring and 0.74 for peripheral segments. Image quality was predicted with a mean absolute error of 0.27 on a 5-point scale, and of all evaluated reliability indices, MOS/inferred MOS proved most important. The findings suggest that QAF allows for reliable testing of autofluorescence levels at the posterior pole in patients with AMD in a multicenter, multioperator setting. Patient reliability indices could serve as eligibility criteria for clinical trials, helping identify patients with adequate retest reliability
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Validating candidate endpoints for intermediate age-related macular degeneration trials in a multi-centre setting—lessons from the MACUSTAR study
For the conduct of future interventional age-related macular degeneration (AMD) trials, the availability of clinical study endpoints is key. However, no endpoints have been accepted by regulators for evaluation of treatment for intermediate (i) AMD, i.e. the AMD stage at highest risk of developing irreversible geographic atrophy or macular neovascularization. The European MACUSTAR consortium has recruited more than 700 individuals to develop and validate structural, functional and patient-reported endpoints, enabling future iAMD trials based on a prospective observational, multi-centre cohort study. Reliably assessing candidate endpoints in a setting that involves multiple clinical sites across countries comes with a plurality of challenges in the study set-up, quality of data, recruitment of participants and study conduct. Therefore, the MACUSTAR consortium has established a framework that successfully addresses these topics, provides relevant insights into the natural history of iAMD and its sub-phenotypes, and will open new regulatory pathways. The MACUSTAR study is registered on ClinicalTrials.gov under NCT03349801
Der Satzbau der erzgebirgischen Mundart /
Vita.Thesis (doctoral) -- Universität Leipzig, 1904.Bibliography: p. [179].Mode of access: Internet
Geldanlage und Vermögensverwaltung : praktischer Ratgeber für alle Kaufleute, Sparer, Rentner und Kapitalisten über dauernde und vorübergehende Anlage von Geldern mit ausführlicher Erläuterung von Kurszettel und Bilanz und Angaben über zweckmässige Auswahl, Aufbewahrung und Verwaltung von Wertpapieren : unter Beifügung zahlreicher Beispiele gemeinverständlich dargestellt /
Includes bibliographical references and index.Mode of access: Internet
Die gesetzlichen Bestimmungen uber die Rechte und Pflichten der Deutschen Apothekergehülfen,
Includes bibliographical references.Mode of access: Internet
Internationale wechselpraxis; die wechselgesetze und wechselstempeltarife sämtlicher staaten Europas und die vorschriften derselben über die versteuerung der wechsel für den praktischen gebrauch,
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Lehrbuch der Chemie zum Gebrauch bei chemischen Vorlesungen, beim Unterricht in höheren Lehranstalten, sowie zum Selbstunterricht.
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