79 research outputs found

    Planetary Science Virtual Observatory architecture

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    In the framework of the Europlanet-RI program, a prototype of Virtual Observatory dedicated to Planetary Science was defined. Most of the activity was dedicated to the elaboration of standards to retrieve and visualize data in this field, and to provide light procedures to teams who wish to contribute with on-line data services. The architecture of this VO system and selected solutions are presented here, together with existing demonstrators

    The EPN-TAP protocol for the Planetary Science Virtual Observatory

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    A Data Access Protocol has been set up to search and retrieve Planetary Science data in general. This protocol will allow the user to select a subset of data from an archive in a standard way, based on the IVOA Table Access Protocol (TAP). The TAP mechanism is completed by an underlying Data Model and reference dictionaries. This paper describes the principle of the EPN- TAP protocol and interfaces, underlines the choices that have been made, and discusses possible evolutions.Comment: 21 pages. Submitted to Astronomy & Computing, S.I. Virtual Observator

    Studying Sun-Planet Connections Using the Heliophysics Integrated Observatory (HELIO)

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    The Heliophysics Integrated Observatory (HELIO) is a software infrastructure involving a collection of web services, heliospheric data sources (e.g., solar, planetary, etc.), and event catalogues – all of which are accessible through a unified front end. In this paper we use the HELIO infrastructure to perform three case studies based on solar events that propagate through the heliosphere. These include a coronal mass ejection that intersects both Earth and Mars, a solar energetic particle event that crosses the orbit of Earth, and a high-speed solar wind stream, produced by a coronal hole, that is observed in situ at Earth (L1). A ballistic propagation model is run as one of the HELIO services and used to model these events, predicting if they will interact with a spacecraft or planet and determining the associated time of arrival. The HELIO infrastructure streamlines the method used to perform these kinds of case study by centralising the process of searching for and visualising data, indicating interesting features on the solar disk, and finally connecting remotely observed solar features with those detected by in situ solar wind and energetic particle instruments. HELIO represents an important leap forward in European heliophysics infrastructure by bridging the boundaries of traditional scientific domains

    Proposed antimatter gravity measurement with an antihydrogen beam

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    The principle of the equivalence of gravitational and inertial mass is one of the cornerstones of general relativity. Considerable efforts have been made and are still being made to verify its validity. A quantum-mechanical formulation of gravity allows for non-Newtonian contributions to the force which might lead to a difference in the gravitational force on matter and antimatter. While it is widely expected that the gravitational interaction of matter and of antimatter should be identical, this assertion has never been tested experimentally. With the production of large amounts of cold antihydrogen at the CERN Antiproton Decelerator, such a test with neutral antimatter atoms has now become feasible. For this purpose, we have proposed to set up the AEGIS experiment at CERN/AD, whose primary goal will be the direct measurement of the Earth's gravitational acceleration on antihydrogen with a classical Moiré deflectometer. © 2007 Elsevier B.V. All rights reserved

    Magnetic Reconnection inside a Flux Transfer Event‐like structure in Magnetopause Kelvin‐Helmholtz Waves

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    This is the final version. Available from the American Geophysical Union via the DOI in this recordMMS data are available from https://lasp.colorado.edu/mms/sdc/public/Magnetopause Kelvin‐Helmholtz (KH) waves are believed to mediate solar wind plasma transport via small‐scale mechanisms. Vortex‐induced reconnection (VIR) was predicted in simulations and recently observed using NASA's Magnetospheric Multiscale (MMS) mission data. Flux Transfer Events (FTEs) produced by VIR at multiple locations along the periphery of KH waves were also predicted in simulations but detailed observations were still lacking. Here we report MMS observations of an FTE‐type structure in a KH wave trailing edge during KH activity on 5 May 2017 on the dawnside flank magnetopause. The structure is characterised by (1) bipolar magnetic B Y variation with enhanced core field (B Z ) and (2) enhanced total pressure with dominant magnetic pressure. The cross‐section size of the FTE is found to be consistent with vortex‐induced flux ropes predicted in the simulations. Unexpectedly, we observe an ion jet (V Y ), electron parallel heating, ion and electron density enhancements, and other signatures that can be interpreted as a reconnection exhaust at the FTE central current sheet. Moreover, pitch angle distributions of suprathermal electrons on either side of the current sheet show different properties, indicating different magnetic connectivities. This FTE‐type structure may thus alternatively be interpreted as two interlaced flux tubes with reconnection at the interface as reported by Kacem et al. (2018) and Øieroset et al. (2019). The structure may be the result of interaction between two flux tubes, likely produced by multiple VIR at the KH wave trailing edge, and constitutes a new class of phenomenon induced by KH waves.Science and Technology Facilities Council (STFC)Thailand Science Research and InnovationNAS

    «La relation de limitation et d’exception dans le français d’aujourd’hui : exceptĂ©, sauf et hormis comme pivots d’une relation algĂ©brique »

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    L’analyse des emplois prĂ©positionnels et des emplois conjonctifs d’ “exceptĂ©â€, de “sauf” et d’ “hormis” permet d’envisager les trois prĂ©positions/conjonctions comme le pivot d’un binĂŽme, comme la plaque tournante d’une structure bipolaire. PlacĂ©es au milieu du binĂŽme, ces prĂ©positions sont forcĂ©es par leur sĂ©mantisme originaire dĂ»ment mĂ©taphorisĂ© de jouer le rĂŽle de marqueurs d’inconsĂ©quence systĂ©matique entre l’élĂ©ment se trouvant Ă  leur gauche et celui qui se trouve Ă  leur droite. L’opposition qui surgit entre les deux Ă©lĂ©ments n’est donc pas une incompatibilitĂ© naturelle, intrinsĂšque, mais extrinsĂšque, induite. Dans la plupart des cas (emplois limitatifs), cette opposition prend la forme d’un rapport entre une « classe » et le « membre (soustrait) de la classe », ou bien entre un « tout » et une « partie » ; dans d’autres (emplois exceptifs), cette opposition se manifeste au contraire comme une attaque de front portĂ©e par un « tout » Ă  un autre « tout ». De plus, l’inconsĂ©quence induite mise en place par la prĂ©position/conjonction paraĂźt, en principe, tout Ă  fait insurmontable. Dans l’assertion « les Ă©cureuils vivent partout, sauf en Australie » (que l’on peut expliciter par « Les Ă©cureuils vivent partout, sauf [qu’ils ne vivent pas] en Australie »), la prĂ©position semble en effet capable d’impliquer le prĂ©dicat principal avec signe inverti, et de bĂątir sur une telle implication une sorte de sous Ă©noncĂ© qui, Ă  la rigueur, est totalement inconsĂ©quent avec celui qui le prĂ©cĂšde (si « les Ă©cureuils ne vivent pas en Australie », le fait qu’ils « vivent partout » est faux). NĂ©anmoins, l’analyse montre qu’alors que certaines de ces oppositions peuvent enfin ĂȘtre dĂ©passĂ©es, d’autres ne le peuvent pas. C’est, respectivement, le cas des relations limitatives et des relations exceptives. La relation limitative, impliquant le rapport « tout » - « partie », permet de rĂ©soudre le conflit dans les termes d’une somme algĂ©brique entre deux sous Ă©noncĂ©s pourvus de diffĂ©rent poids informatif et de signe contraire. Les valeurs numĂ©riques des termes de la somme Ă©tant dĂ©sĂ©quilibrĂ©es, le rĂ©sultat est toujours autre que zĂ©ro. La relation exceptive, au contraire, qui n’implique pas le rapport « tout » - « partie », n’est pas capable de rĂ©soudre le conflit entre deux sous Ă©noncĂ©s pourvus du mĂȘme poids informatif et en mĂȘme temps de signe contraire : les valeurs numĂ©riques des termes de la somme Ă©tant symĂ©triques et Ă©gales, le rĂ©sultat sera toujours Ă©quivalent Ă  zĂ©ro

    Impact of clinical phenotypes on management and outcomes in European atrial fibrillation patients: a report from the ESC-EHRA EURObservational Research Programme in AF (EORP-AF) General Long-Term Registry

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    Background: Epidemiological studies in atrial fibrillation (AF) illustrate that clinical complexity increase the risk of major adverse outcomes. We aimed to describe European AF patients\u2019 clinical phenotypes and analyse the differential clinical course. Methods: We performed a hierarchical cluster analysis based on Ward\u2019s Method and Squared Euclidean Distance using 22 clinical binary variables, identifying the optimal number of clusters. We investigated differences in clinical management, use of healthcare resources and outcomes in a cohort of European AF patients from a Europe-wide observational registry. Results: A total of 9363 were available for this analysis. We identified three clusters: Cluster 1 (n = 3634; 38.8%) characterized by older patients and prevalent non-cardiac comorbidities; Cluster 2 (n = 2774; 29.6%) characterized by younger patients with low prevalence of comorbidities; Cluster 3 (n = 2955;31.6%) characterized by patients\u2019 prevalent cardiovascular risk factors/comorbidities. Over a mean follow-up of 22.5 months, Cluster 3 had the highest rate of cardiovascular events, all-cause death, and the composite outcome (combining the previous two) compared to Cluster 1 and Cluster 2 (all P <.001). An adjusted Cox regression showed that compared to Cluster 2, Cluster 3 (hazard ratio (HR) 2.87, 95% confidence interval (CI) 2.27\u20133.62; HR 3.42, 95%CI 2.72\u20134.31; HR 2.79, 95%CI 2.32\u20133.35), and Cluster 1 (HR 1.88, 95%CI 1.48\u20132.38; HR 2.50, 95%CI 1.98\u20133.15; HR 2.09, 95%CI 1.74\u20132.51) reported a higher risk for the three outcomes respectively. Conclusions: In European AF patients, three main clusters were identified, differentiated by differential presence of comorbidities. Both non-cardiac and cardiac comorbidities clusters were found to be associated with an increased risk of major adverse outcomes
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