40 research outputs found
Polarization control of high order harmonics in the EUV photon energy range
International audienceWe report the generation of circularly polarized high order harmonics in the extreme ultraviolet range (18-27 nm) from a linearly polarized infrared laser (40 fs, 0.25 TW) focused into a neon filled gas cell. To circularly polarize the initially linearly polarized harmonics we have implemented a four-reflector phase-shifter. Fully circularly polarized radiation has been obtained with an efficiency of a few percents, thus being significantly more efficient than currently demonstrated direct generation of elliptically polarized harmonics. This demonstration opens up new experimental capabilities based on high order harmonics, for example, in biology and materials science. The inherent femtosecond time resolution of high order harmonic generating table top laser sources renders these an ideal tool for the investigation of ultrafast magnetization dynamics now that the magnetic circular dichroism at the absorption M-edges of transition metals can be exploite
Chapitre 10 - Co-conception de changements techniques et organisationnels au sein des systĂšmes agricoles
RĂ©sumĂ©. Les mutations en cours au sein de lâagriculture interrogent les travaux et les mĂ©thodes relatifs Ă la conception de systĂšmes agricoles innovants. Ce chapitre analyse la spĂ©cificitĂ© de cinq dĂ©marches de co-conception de systĂšmes techniques testĂ©es en France et dans diffĂ©rents pays dâAfrique et dâAmĂ©rique latine. Elles se basent sur des interactions fortes entre les acteurs impliquĂ©s dans ces dĂ©marches, facilitĂ©es par une diversitĂ© dâobjets intermĂ©diaires tels que la modĂ©lisation ou lâexpĂ©rimentation agronomique en milieu paysan. Elles ont permis de produire des connaissances opĂ©rationnelles et scientifiques sur des changements techniques et leurs conditions de mise en Ćuvre Ă lâĂ©chelle de lâexploitation ainsi que sur les conditions institutionnelles favorables Ă lâĂ©mergence de nouveaux systĂšmes. Ces dĂ©marches mobilisent des compĂ©tences ne relevant pas seulement de lâagronomie. LâintĂ©gration de chercheurs relevant des sciences humaines sâavĂšre centrale, en particulier pour analyser comment hybrider des connaissances multiples en vue dâaccompagner lâinnovation au sein des exploitations et des territoires
VirHostNet: a knowledge base for the management and the analysis of proteome-wide virusâhost interaction networks
Infectious diseases caused by viral agents kill millions of people every year. The improvement of prevention and treatment of viral infections and their associated diseases remains one of the main public health challenges. Towards this goal, deciphering virusâhost molecular interactions opens new perspectives to understand the biology of infection and for the design of new antiviral strategies. Indeed, modelling of an infection network between viral and cellular proteins will provide a conceptual and analytic framework to efficiently formulate new biological hypothesis at the proteome scale and to rationalize drug discovery. Therefore, we present the first release of VirHostNet (VirusâHost Network), a public knowledge base specialized in the management and analysis of integrated virusâvirus, virusâhost and hostâhost interaction networks coupled to their functional annotations. VirHostNet integrates an extensive and original literature-curated dataset of virusâvirus and virusâhost interactions (2671 non-redundant interactions) representing more than 180 distinct viral species and one of the largest human interactome (10 672 proteins and 68 252 non-redundant interactions) reconstructed from publicly available data. The VirHostNet Web interface provides appropriate tools that allow efficient query and visualization of this infected cellular network. Public access to the VirHostNet knowledge-based system is available at http://pbildb1.univ-lyon1.fr/virhostnet
Innovation et développement dans les systÚmes agricoles et alimentaires
Lâinnovation est souvent prĂ©sentĂ©e comme lâun des principaux leviers pour promouvoir un dĂ©veloppement plus durable et plus inclusif. Dans les domaines de lâagriculture et de lâalimentation, lâinnovation est marquĂ©e par des spĂ©cificitĂ©s liĂ©es Ă sa relation Ă la nature, mais aussi Ă la grande diversitĂ© dâacteurs concernĂ©s, depuis les agriculteurs jusquâaux consommateurs, en passant par les services de recherche et de dĂ©veloppement. Lâinnovation Ă©merge des interactions entre ces acteurs, qui mobilisent des ressources et produisent des connaissances dans des dispositifs collaboratifs, afin de gĂ©nĂ©rer des changements. Elle recouvre des domaines aussi variĂ©s que les pratiques de production, lâorganisation des marchĂ©s, ou les pratiques alimentaires. Lâinnovation est reliĂ©e aux grands enjeux de dĂ©veloppement : innovation agro-Ă©cologique, innovation sociale, innovation territoriale, etc. Cet ouvrage porte un regard sur lâinnovation dans les systĂšmes agricoles et alimentaires. Il met un accent particulier sur lâaccompagnement de lâinnovation, en interrogeant les mĂ©thodes et les organisations, et sur lâĂ©valuation de lâinnovation au regard de diffĂ©rents critĂšres. Il sâappuie sur des rĂ©flexions portĂ©es par diffĂ©rentes disciplines scientifiques, sur des travaux de terrain conduits tant en France que dans de nombreux pays du Sud, et enfin sur les expĂ©riences acquises en accompagnant des acteurs qui innovent. Il combine des synthĂšses sur lâinnovation et des Ă©tudes de cas emblĂ©matiques pour illustrer les propos. Lâouvrage est destinĂ© aux enseignants, professionnels, Ă©tudiants et chercheurs
Evaluation de la permanence des soins dans le Pas-de-Calais (Ă©tude prospective sur quatre jours des patients consultant aux urgences)
Objectifs : Ă©valutation de la permanence des soins par l Ă©tude des patients entrant aux urgences : leur orientation et parcours prĂ©alables, les examens rĂ©alisĂ©s aux urgences et l orientation finale qui en rĂ©sulte. Ăvaluation de l adĂ©quation du recours aux urgences et de la pathologie. Tentative de dĂ©crire une population type ne nĂ©cessitant pas ce recours en urgence. Proposer une filiĂšre adaptĂ©e Ă ces patients. Type d Ă©tude :Ătude multicentrique, prospective, descriptive, analytique et observationnelle. MatĂ©riel et MĂ©thode : sur une pĂ©riode de quatre jours et trois nuit, du vendredi matin au lundi soir suivant Ă minuit, recueil des donnĂ©es pour tout patient se prĂ©sentant aux urgences, quel que soit le motif de recours, dans les services d urgence des centres hospitaliers du dĂ©partement du Pas-de- Calais. PrĂ©cision de l orientation et du mode et de la date d entrĂ©e du patient. RelevĂ© de la consommation de soins aux urgences (consultation simple, examens complĂ©mentaires paracliniques et avis spĂ©cialisĂ©). Devenir du patient aprĂšs son passage (hospitalisation, sortie avec ou sans examen). RĂ©sultats : Durant la pĂ©riode d observation et aprĂšs la rĂ©alisation d un Ă©chantillon stable, 1203 patients ont fait l objet d une analyse. La moyenne d Ăąge Ă©tait de 30 ans. Les femmes Ă©taient en moyenne plus ĂągĂ©es que les hommes. 93,3% des patients ont une complĂ©mentaire santĂ©, dont 16,5% la CMU. La plupart des patients interrogĂ©s dĂ©clarent avoir un mĂ©decin traitant. 30,9% des passages aux urgences aboutissent Ă une hospitalisation et 22,5% sortent sans examen complĂ©mentaire, aprĂšs moins de 3 heures. Plus l Ăąge est Ă©levĂ©, plus on rĂ©alise d examens et d hospitalisations. Les facteurs influençant la sortie sans examen complĂ©mentaire sont l Ăąge jeune, l entrĂ©e aux urgences entre 20 heures et 7 heures du matin, l arrivĂ©e aux urgences par ses propres moyens, le fait de n ĂȘtre pas adressĂ© et de ne pas avoir de courrier de son mĂ©decin traitant. Il existe un effet centre. Le sentiment d urgence ressenti par le patient n est pas discriminant. Les pompiers sont la principale modalitĂ© d entrĂ©e aux urgences en nuit profonde. Conclusion : 22, 5% des passages aux urgences ne sont pas justifiĂ©s selon nos critĂšres. La prise en charge des patients ĂągĂ©s est inadaptĂ©e aux urgences. Des solutions alternatives doivent ĂȘtre encouragĂ©es et dĂ©veloppĂ©es.LILLE2-BU SantĂ©-Recherche (593502101) / SudocSudocFranceF
High Fidelity Pressure Wires Provide Accurate Validation of Non-Invasive Central Blood Pressure and Pulse Wave Velocity Measurements
Central blood pressure (cBP) is known to be a better predictor of the damage caused by hypertension in comparison with peripheral blood pressure. During cardiac catheterization, we measured cBP in the ascending aorta with a fluid-filled guiding catheter (FF) in 75 patients and with a high-fidelity micromanometer tipped wire (FFR) in 20 patients. The wire was withdrawn into the brachial artery and aorto-brachial pulse wave velocity (abPWV) was calculated from the length of the pullback and the time delay between the ascending aorta and the brachial artery pulse waves by gating to the R-wave of the ECG for both measurements. In 23 patients, a cuff was inflated around the calf and an aorta-tibial pulse wave velocity (atPWV) was calculated from the distance between the cuff around the leg and the axillary notch and the time delay between the ascending aorta and the tibial pulse waves. Brachial BP was measured non-invasively and cBP was estimated using a new suprasystolic oscillometric technology. The mean differences between invasively measured cBP by FFR and non-invasive estimation were â0.4 ± 5.7 mmHg and by FF 5.4 ± 9.4 mmHg in 52 patients. Diastolic and mean cBP were both overestimated by oscillometry, with mean differences of â8.9 ± 5.5 mmHg and â6.4 ± 5.1 mmHg compared with the FFR and â10.6 ± 6.3 mmHg and â5.9 ± 6.2 mmHg with the FF. Non-invasive systolic cBP compared accurately with the high-fidelity FFR measurements, demonstrating a low bias (â€5 mmHg) and high precision (SD †8 mmHg). These criteria were not met when using the FF measurements. Invasively derived average Ao-brachial abPWV was 7.0 ± 1.4 m/s and that of Ao-tibial atPWV was 9.1 ± 1.8 m/s. Non-invasively estimated PWV based on the reflected wave transit time did not correlate with abPWV or with atPWV. In conclusion, we demonstrate the advantages of a novel method of validation for non-invasive cBP monitoring devices using acknowledged gold standard FFR wire transducers and the possibility to easily measure PWV during coronary angiography with the impact of cardiovascular risk factors
Bioresorbable Magnesium-Based Stent: Real-World Clinical Experience and Feasibility of Follow-Up by Coronary Computed Tomography: A New Window to Look at New Scaffolds
(1) Background: The diagnostic accuracy of coronary computed tomography angiography (CCTA) for coronary artery disease (CAD) has greatly improved so CCTA represents a transition in the care of patients suffering from CAD. Magnesium-based bioresorbable stents (Mg-BRS) secure acute percutaneous coronary intervention (PCI) results without leaving, in the long term, a metallic caging effect. The purpose of this real-world study was to assess clinical and CCTA medium- and long-term follow-up of all our patients with implanted Mg-BRS. (2) Methods: The patency of 52 Mg-BRS implanted in 44 patients with de novo lesions (24 of which had acute coronary syndrome (ACS)) was evaluated by CCTA and compared to quantitative coronary angiography (QCA) post-implantation. (3) Results: ten events including four deaths occurred during a median follow-up of 48 months. CCTA was interpretable and in-stent measurements were successful at follow-up without being hindered by the stent strutâs âblooming effectâ. Minimal in-stent diameters on CCTA were found to be 1.03 ± 0.60 mm smaller than the expected diameter after post-dilation on implantation (p < 0.05), a difference not found in comparing CCTA and QCA. (4) Conclusions: CCTA follow-up of implanted Mg-BRS is fully interpretable and we confirm the long-term Mg-BRS safety profile
Chimie de synthÚse : paramÚtres diélectriques de systÚmes isolés et de mélanges réactionnels. III : Traitement micro-ondes. PhénomÚnes athermiques
National audienc
A tentative reconstruction of the last interglacial and glacial inception in Greenland based on new gas measurements in the Greenland Ice Core Project (GRIP) ice core
International audienceThe disturbed stratigraphy of the ice in the lowest 10% of the Greenland GRIP ice core prevents direct access to climatic information older than 110 kyr. This is especially regretful since this period covers the previous interglacial corresponding to marine isotopic stage 5e (MIS 5e, 130-120 kyr B.P.). Here we present a tentative reconstruction of the disturbed GRIP chronology based on the succession of globally well mixed gas parameters. The GRIP d 18 O ice chronological sequence is obtained by comparing a new set of d 18 O of atmospheric O 2 and CH 4 measurements from the bottom section of the GRIP core with their counterpart in the Vostok Antarctic profiles. This comparison clearly identifies ice from the penultimate glacial maximum (MIS 6, 190-130 kyr B.P.) in the GRIP core. Further it allows rough reconstruction of the last interglacial period and of the last glacial inception in Greenland which appears to lay its Antarctic counterpart. Our data suggest that while Antarctica is already entering into a glaciation, Greenland is still experiencing a warm maximum during MIS 5e