1,884 research outputs found

    Major results from the first plasma campaign of the Wendelstein 7-X stellarator

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    After completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning the device, first plasma operation started at the end of 2015. Integral commissioning of plasma start-up and operation using electron cyclotron resonance heating (ECRH) and an extensive set of plasma diagnostics have been completed, allowing initial physics studies during the first operational campaign. Both in helium and hydrogen, plasma breakdown was easily achieved. Gaining experience with plasma vessel conditioning, discharge lengths could be extended gradually. Eventually, discharges lasted up to 6 s, reaching an injected energy of 4 MJ, which is twice the limit originally agreed for the limiter configuration employed during the first operational campaign. At power levels of 4 MW central electron densities reached 3 x 1019 m-3, central electron temperatures reached values of 7 keV and ion temperatures reached just above 2 keV. Important physics studies during this first operational phase include a first assessment of power balance and energy confinement, ECRH power deposition experiments, 2nd harmonic O-mode ECRH using multi-pass absorption, and current drive experiments using electron cyclotron current drive. As in many plasma discharges the electron temperature exceeds the ion temperature significantly, these plasmas are governed by core electron root confinement showing a strong positive electric field in the plasma centre.This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the EURATOM research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission

    Psychometric properties of the Caregiver Preparedness Scale in caregivers of stroke survivors

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    Objective: To evaluate the psychometric characteristics of the Caregiver Preparedness Scale (CPS) in caregivers of stroke survivors. Background: Caregiver preparedness can have an important impact on both the caregiver and the stroke survivor. The validity and reliability of the CPS has not been tested for the stroke-caregiver population. Methods: We used a cross-sectional design to study a sample of 156 caregivers of stroke survivors. Construct validity of the CPS was evaluated by confirmatory factor analysis (CFA). Internal consistency and test-retest reliability were also evaluated. Results: Caregivers were, on average, 54 year old (SD ¼ 13.2) and most were women (64.7%). CFA supported the unidimensionality of the scale (comparative fit index ¼ 0.98). Reliability was also supported: item-reliability index and itemetotal correlations above 0.30; composite reliability index ¼ 0.93; Cronbach’s alpha ¼ 0.94; factor score determinacy ¼ 0.97; and test-retest reliability ¼ 0.92. Conclusion: The CPS is valid and reliable in caregivers of stroke survivors. Scores on this scale may assist health-care providers in identifying caregivers with less preparedness to provide specific interventions

    Fully Convolutional Networks for Continuous Sign Language Recognition

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    Continuous sign language recognition (SLR) is a challenging task that requires learning on both spatial and temporal dimensions of signing frame sequences. Most recent work accomplishes this by using CNN and RNN hybrid networks. However, training these networks is generally non-trivial, and most of them fail in learning unseen sequence patterns, causing an unsatisfactory performance for online recognition. In this paper, we propose a fully convolutional network (FCN) for online SLR to concurrently learn spatial and temporal features from weakly annotated video sequences with only sentence-level annotations given. A gloss feature enhancement (GFE) module is introduced in the proposed network to enforce better sequence alignment learning. The proposed network is end-to-end trainable without any pre-training. We conduct experiments on two large scale SLR datasets. Experiments show that our method for continuous SLR is effective and performs well in online recognition.Comment: Accepted to ECCV202

    G-band Spectral Synthesis in Solar Magnetic Concentrations

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    Narrow band imaging in the G-band is commonly used to trace the small magnetic field concentrations of the Sun, although the mechanism that makes them bright has remained unclear. We carry out LTE syntheses of the G-band in an assorted set of semi-empirical model magnetic concentrations. The syntheses include all CH lines as well as the main atomic lines within the band-pass. The model atmospheres produce bright G-band spectra having many properties in common with the observed G-band bright points. In particular, the contrast referred to the quiet Sun is about twice the contrast in continuum wavelengths. The agreement with observations does not depend on the specificities of the model atmosphere, rather it holds from single fluxtubes to MIcro-Structured Magnetic Atmospheres. However, the agreement requires that the real G-band bright points are not spatially resolved, even in the best observations. Since the predicted G-band intensities exceed by far the observed values, we foresee a notable increase of contrast of the G-band images upon improvement of the angular resolution. According to the LTE modeling, the G-band spectrum emerges from the deep photosphere that produces the continuum. Our syntheses also predict solar magnetic concentrations showing up in continuum images but not in the G-band . Finally, we have examined the importance of the CH photo-dissociation in setting the amount of G-band absorption. It turns out to play a minor role.Comment: To appear in ApJ, 554 n2 Jun 20, 33 pages and 9 figure

    When the path is never shortest: a reality check on shortest path biocomputation

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    Shortest path problems are a touchstone for evaluating the computing performance and functional range of novel computing substrates. Much has been published in recent years regarding the use of biocomputers to solve minimal path problems such as route optimisation and labyrinth navigation, but their outputs are typically difficult to reproduce and somewhat abstract in nature, suggesting that both experimental design and analysis in the field require standardising. This chapter details laboratory experimental data which probe the path finding process in two single-celled protistic model organisms, Physarum polycephalum and Paramecium caudatum, comprising a shortest path problem and labyrinth navigation, respectively. The results presented illustrate several of the key difficulties that are encountered in categorising biological behaviours in the language of computing, including biological variability, non-halting operations and adverse reactions to experimental stimuli. It is concluded that neither organism examined are able to efficiently or reproducibly solve shortest path problems in the specific experimental conditions that were tested. Data presented are contextualised with biological theory and design principles for maximising the usefulness of experimental biocomputer prototypes.Comment: To appear in: Adamatzky, A (Ed.) Shortest path solvers. From software to wetware. Springer, 201

    INFN Camera demonstrator for the Cherenkov Telescope Array

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    The Cherenkov Telescope Array is a world-wide project for a new generation of ground-based Cherenkov telescopes of the Imaging class with the aim of exploring the highest energy region of the electromagnetic spectrum. With two planned arrays, one for each hemisphere, it will guarantee a good sky coverage in the energy range from a few tens of GeV to hundreds of TeV, with improved angular resolution and a sensitivity in the TeV energy region better by one order of magnitude than the currently operating arrays. In order to cover this wide energy range, three different telescope types are envisaged, with different mirror sizes and focal plane features. In particular, for the highest energies a possible design is a dual-mirror Schwarzschild-Couder optical scheme, with a compact focal plane. A silicon photomultiplier (SiPM) based camera is being proposed as a solution to match the dimensions of the pixel (angular size of ~ 0.17 degrees). INFN is developing a camera demonstrator made by 9 Photo Sensor Modules (PSMs, 64 pixels each, with total coverage 1/4 of the focal plane) equipped with FBK (Fondazione Bruno Kessler, Italy) Near UltraViolet High Fill factor SiPMs and Front-End Electronics (FEE) based on a Target 7 ASIC, a 16 channels fast sampler (up to 2GS/s) with deep buffer, self-trigger and on-demand digitization capabilities specifically developed for this purpose. The pixel dimensions of 6Ă—66\times6 mm2^2 lead to a very compact design with challenging problems of thermal dissipation. A modular structure, made by copper frames hosting one PSM and the corresponding FEE, has been conceived, with a water cooling system to keep the required working temperature. The actual design, the adopted technical solutions and the achieved results for this demonstrator are presented and discussed.Comment: In Proceedings of the 34th International Cosmic Ray Conference (ICRC2015), The Hague, The Netherlands. All CTA contributions at arXiv:1508.0589

    Influence of age on the occurrence of adverse events in rheumatic patients at the onset of biological treatment : Data from the BIOBADASER III register

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    To assess whether age, at the beginning of biologic treatment, is associated with the time a first adverse event (AE) appears in patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS), or psoriatic arthritis (PsA). All patients in the BIOBADASER registry diagnosed with RA, AS, and PsA, and classified as young ( 75 years old) at start of biological treatment were included. Factors associated with the appearance of a first AE using adjusted incidence rate ratios (IRR) (Poisson regression) were analyzed. Survival to first AE was studied by Kaplan-Meier analysis and hazard ratios (HR) by Cox regression. 2483 patients were included: 1126 RA, 680 PsA, and 677 AS. Age group stratification was as follows: 63 young, 2127 adults, 237 elderly, and 56 very elderly. Regression model revealed an increased probability of suffering a first AE at age 65 years or older [IRR elderly: 1.42 (CI95% 1.13-1.77)]. Other characteristics associated with AE were female gender, the use of DMARDs, including methotrexate, the presence of comorbidities, and the time of disease duration. Factors that had the greatest impact on survival over a first AE were age > 75 years [HR 1.50 (1.01-2.24)] and female gender [HR 1.42 (1.22-1.64)]. Age at the start of treatment and female gender are key factors associated with the appearance of a first AE with biologics. Other factors related to patient status and treatment were also associated with a first AE in rheumatic patients treated with biologics

    Relationship between Determinants of Health, Equity, and Dimensions of Health Literacy in Patients with Cardiovascular Disease

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    Background: Health literacy (HL) has been linked to empowerment, use of health services, and equity. Evaluating HL in people with cardiovascular health problems would facilitate the development of suitable health strategies care and reduce inequity. Aim: To investigate the relationship between different dimensions that make up HL and social determinants in patients with cardiovascular disease. Methods: Observational, descriptive, cross-sectional study in patients with cardiovascular disease, aged 50-85 years, accessing primary care services in Valencia (Spain) in 2018-2019. The Health Literacy Questionnaire was used. Results: 252 patients. Age was significantly related with the ability to participate with healthcare providers (p = 0.043), ability to find information (p = 0.022), and understanding information correctly to know what to do (p = 0.046). Level of education was significant for all HL dimensions. Patients without studies scored lower in all dimensions. The low- versus middle-class social relationship showed significant results in all dimensions. Conclusions: In patients with cardiovascular disease, level of education and social class were social determinants associated with HL scores. Whilst interventions at individual level might address some HL deficits, inequities in access to cardiovascular care and health outcomes would remain unjustly balanced unless structural determinants of HL are taken into account

    Subharmonic bifurcation cascade of pattern oscillations caused by winding number increasing entrainment

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    Convection structures in binary fluid mixtures are investigated for positive Soret coupling in the driving regime where solutal and thermal contributions to the buoyancy forces compete. Bifurcation properties of stable and unstable stationary square, roll, and crossroll (CR) structures and the oscillatory competition between rolls and squares are determined numerically as a function of fluid parameters. A novel type of subharmonic bifurcation cascade (SC) where the oscillation period grows in integer steps as n(2π)/(ω)n (2\pi)/(\omega) is found and elucidated to be an entrainment process.Comment: 7 pages, 4 figure

    Morphological stabilization and KPZ scaling by electrochemically induced co-deposition of nanostructured NiW alloy films

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    We have assessed the stabilizing role that induced co-deposition has in the growth of nanostructured NiW alloy films by electrodeposition on polished steel substrates, under pulsed galvanostatic conditions. We have compared the kinetic roughening properties of NiW films with those of Ni films deposited under the same conditions, as assessed by Atomic Force Microscopy. The surface morphologies of both systems are super-rough at short times, but differ at long times: while a cauliflower-like structure dominates for Ni, the surfaces of NiW films display a nodular morphology consistent with more stable, conformal growth, whose height fluctuations are in the Kardar-ParisiZhang universality class of rough two-dimensional interfaces. These differences are explained by the mechanisms controlling surface growth in each case: mass transport through the electrolyte (Ni) and attachment of the incoming species to the growing interface (NiW). Thus, the long-time conformal growth regime is characteristic of electrochemical induced co-deposition under current conditions in which surface kinetics is hindered due to a complex reaction mechanism. These results agree with a theoretical model of surface growth in diffusion-limited systems, in which the key parameter is the relative importance of mass transport with respect to the kinetics of the attachment reaction.We acknowledge financial support from ANPCyT (PICT 2012-1808), CONICET (PIP 0671) and Universidad Nacional de La Plata (11X760) as well as from MINECO/FEDER (Spain/UE) Grants MAT2014-54231-C4-1-P, FIS2015-66020-C2-1-P and MAT2014-52405-C2-2-R, as well as by Comunidad AutĂłnoma de Madrid (Spain) Grant NANOAVANSENS S2013/MIT-3029. M.E.V. is member of the research career of CICPB
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