135 research outputs found
Cantons de Falaise (14) et de Putanges-Pont-Ăcrepin (61)
Dans le cadre dâune Ă©tude sur le choix de certaines sĂ©ries microtoponymiques comme indicateur pouvant rĂ©vĂ©ler une prĂ©sence Ă©ventuelle dâune occupation humaine, la campagne de prospection, menĂ©e dans les cantons de Falaise (14) et de Putanges-Pont-Ăcrepin (61) depuis les annĂ©es 2009 et 2010, a Ă©tĂ© poursuivie en 2015. Cette annĂ©e, celle-ci sâest dĂ©roulĂ©e du printemps Ă lâautomne et a concernĂ© quelques communes, deux dans le canton de Falaise-Nord (14), Noron-lâAbbaye et Ussy, et 3 dans le canto..
Canton de Briouze
En 2016, une campagne de prospection a Ă©tĂ© engagĂ©e sur le canton de Briouze, notamment sur les trois communes situĂ©es Ă lâest de la Rouvre, CramĂ©nil, Saint-AndrĂ©-de-Briouze et Saint-Hilaire-de-Briouze, sur lesquelles certains microtoponymes pouvaient laisser supposer la prĂ©sence de sites. Il sâagissait Ă©galement de prospecter les parcelles environnant les points de passages qui permettent Ă dâanciens axes de communication, notamment ceux reliant Sainte-Croix-Orne aux Tourailles et ĂcouchĂ© Ă B..
Cantons de Falaise (14) et Putanges-Pont-Ăcrepin (61)
Dans le cadre dâune Ă©tude sur le choix de certaines sĂ©ries microtoponymiques comme indicateur pouvant rĂ©vĂ©ler une prĂ©sence Ă©ventuelle dâune occupation humaine, la campagne de prospection, menĂ©e dans les cantons de Falaise (14) et de Putanges-Pont-Ăcrepin (61) depuis les annĂ©es 2009 et 2010, a Ă©tĂ© poursuivie en 2014. Cette annĂ©e, celle-ci a Ă©tĂ© trĂšs brĂšve. Seules deux communes du canton de Falaise ont fait lâobjet de prospections sur une petite partie de leur territoire, Noron-lâAbbaye, au sud..
Communes de Craménil, Saint-André-de-Briouze, Saint-Hilaire-de-Briouze
En 2017, la campagne de prospection engagĂ©e depuis 2016 sur le canton de Briouze, notamment sur les trois communes situĂ©es Ă lâest de la Rouvre, CramĂ©nil, Saint-AndrĂ©-de-Briouze et Saint-Hilaire-de-Briouze, sur lesquelles certains microtoponymes pourraient laisser supposer la prĂ©sence Ă©ventuelle dâindices de sites a Ă©tĂ© poursuivie. Il sâagissait Ă©galement de prospecter les parcelles environnant les points de passages qui permettent Ă dâanciens axes de communication, notamment ceux reliant Sai..
Canton de Falaise nord
Date de l'opĂ©ration : 2009 (PI) Dans le cadre dâune Ă©tude sur le choix de certaines sĂ©ries microtoponymiques comme indicateur pouvant rĂ©vĂ©ler une prĂ©sence Ă©ventuelle dâune occupation humaine, une campagne de prospection a Ă©tĂ© menĂ©e sur des parcelles de certaines communes du canton au cours de lâautomne 2009. Si la prospection pĂ©destre sâest avĂ©rĂ©e infructueuse sur certaines dâentre elles (peu dâindices rĂ©vĂ©lateurs, champs en herbages), elle a cependant permis dâidentifier la prĂ©sence de quelq..
Cantons de Falaise (14) et Putanges-Pont-Ăcrepin (61)
Dans le cadre dâune Ă©tude sur le choix de certaines sĂ©ries microtoponymiques comme indicateur pouvant rĂ©vĂ©ler la prĂ©sence Ă©ventuelle dâune occupation humaine, la campagne de prospection, menĂ©e dans les cantons de Falaise (14) et de Putanges-Pont-Ăcrepin (61) depuis les annĂ©es 2009 et 2010, a Ă©tĂ© poursuivie en 2013. Cette annĂ©e, celle-ci a Ă©tĂ© brĂšve, sâest dĂ©roulĂ©e sur quelques jours dâaoĂ»t Ă novembre et nâa pas permis de prospecter toutes les communes envisagĂ©es. Seules quatre communes ont pu..
Canton de Briouze
En 2018, la campagne de prospection engagĂ©e depuis 2016 sur le canton de Briouze, notamment sur les trois communes situĂ©es Ă lâest de la Rouvre, CramĂ©nil, Saint-AndrĂ©-de-Briouze et Saint-Hilaire-de-Briouze, sur lesquelles certains microtoponymes pourraient laisser supposer la prĂ©sence Ă©ventuelle dâindices de site, a Ă©tĂ© poursuivie. Elle sâest dĂ©roulĂ©e, cette annĂ©e, essentiellement sur la commune de Saint-Hilaire-de-Briouze. Les prospections effectuĂ©es sur quelques parcelles de cette commune, ..
Influence of autoionizing states on the pulse-length dependence of strong-field Ne+ photoionization at 38.4 eV
International audienceUsing the time-dependent R-matrix approach, we investigate ionization of ground-state Ne +, irradiated by laser light with a photon energy of 38.4 eV at intensities 10 13 W cm â2, 2 Ă 10 13 W cm â2 and 10 14 W cm â2 as a function of pulse length. Although the photon energy is below the threshold for single-photon ionization, we obtain a significant contribution from single-photon ionization to the ionization probability due to the finite duration of the pulse. The two-photon ionization rates deduced from the calculations are consistent with those obtained in R-matrix-Floquet rate calculations. The ionization probability oscillates with pulse length, which is ascribed to population and depopulation of autoionizing states just above the Ne 2+ ground state, reached after absorption of a single photon. At an intensity of 10 14 W cm â2, pulse lengths longer than 50 cycles are required for two-photon ionization to dominate the ionization probability. Letter to the Editor 2 The development of free-electron lasers operating in the VUV and the X-ray domain has given experimentalists new ways of investigating multi-electron dynamics in strong laser fields. These new laser facilities have, for example, enabled experimentalists to investigate two-photon double ionization of Ne in the photon-energy regime where direct two-photon double ionization is energetically allowed, but sequential (Ne â Ne + â Ne 2+) double ionization is energetically not allowed since the photon energy is not sufficient to ionize Ne + with a single photon (eg. Sorokin et al 2007). At larger photon energies, sequential double ionization is allowed, but also in this process one can find signatures of the fact that the two different emission processes are not independent of each other (Fritzsche et al 2008). One of the grand challenges in theoretical atomic physics is the description of multielectron dynamics in complex atoms irradiated by intense laser pulses. Over the last 15 years, great progress has been made in the description of pure two-electron systems in intense laser fields, for example for two-photon double ionization processes (see, for example, Colgan et al 2002, Feng and van der Hart 2003, Laulan et al 2005, Feist et al 2008) as well as for multiphoton double ionization at 390 nm (Parker et al 2006). These calculations require substantial computational resources, such that the direct extension of these techniques to systems with more than two electrons, like Ne, is unfeasible at present. Other approaches are required to describe the behaviour of complex atoms in intense light fields. The most successful approach for the description of complex atoms in intense laser light at present is the R-matrix-Floquet approach. This approach was designed from the outset to treat complex atoms in intense light fields by combining the R-matrix approach with the Floquet Ansatz (Burke et al 1991). It has been applied to a wide range of problems, ranging from strong-field ionization of Ne and Ar at 390 nm, requiring absorption of at least eight and six photons respectively, (van der Hart 2006) to twophoton emission of the inner 1s electron from ground-state Li â (van der Hart 2005). More recently, the R-matrix-Floquet approach has been instrumental in indicating the importance of detailed atomic structure in two-photon ionization of Ne + (Hamonou et al 2008, Hamonou and van der Hart 2008). The theoretical investigation of ionization processes in Ne + is of particular relevance at the moment, due to the large number of strong-field multiple ionization studies on Ne at photon energies in the range between 38 and 50 eV. Ionization yields of various Ne ions were obtained by Sorokin et al (2007) at photon energies below the Ne + ionization threshold and above this threshold. Moshammer et al (2007) obtained detailed recoil momentum spectra for two-photon double ionization of Ne at 44 eV. Rudenko et al (2008) found that these recoil-ion momentum distributions differed strongly from the recoil-ion momentum distributions for two-photon double ionization of He at 44 eV. At 44 eV, sequential double ionization is allowed for Ne, whereas it is not allowed for He. The dominance of sequential double ionization of Ne was demonstrated experimentally by Kurka et al (2009). Whereas in previous work (Hamonou et al 2008, Hamonou and van der Hart 2009)
Chapter 4. Air quality and climate in the Mediterranean region
Ambient air ranks number one among the natural resources vital to human beings, with an average individual daily need of 12 kg. Due to the specificities of the Mediterranean region (sunny, hot and dry climate; long-range transport converging over the basin), air pollution in reactive compounds over the Mediterranean is often higher than in most European inland regions. Climate change (increase in temperature and drought) and anthropogenic pressure (growing population) should significantly impact the regional air quality. As a result, Mediterranean inhabitants who are already regularly exposed to pollutant loads well above WHO air quality recommendations will be further exposed, resulting in an excess of premature deaths. Exposure monitoring and win-win strategies should be developed in the future both to improve air quality and develop a low carbon economy. The evolution of emissions under climate change is not always clear and much uncertainty remains around present emissions from large urban-industrial centers, although recent progress has been made on emissions of the different regional sources of pollutants. It has been established that the regional climate and water cycle are affected by atmospheric chemistry. By reducing solar radiation at the surface, aerosols reduce the yearly average precipitation in the Mediterranean by 10%, which is a major issue since water is already scarce. Aerosols could further reduce precipitations by reducing the size of cloud droplets or through the formation of cloud droplets and ice crystals. Moreover, recent in situ and model experiments indicate that anthropogenic nitrogen and desert dust phosphorus deposition in nutrient-depleted surface seawater favors phytoplankton development, which stimulates the sink of atmospheric CO2 into marine sediments. But Saharan dust deposition by rain also stimulates bacterial growth, which reemits CO2. The net effect of desert dust deposition at large scales needs to be established.Lâair est sans aucun doute la ressource naturelle la plus essentielle Ă lâhomme: chaque jour 12 kg dâair sont nĂ©cessaires Ă sa survie. Du fait des spĂ©cificitĂ©s de la rĂ©gion mĂ©diterranĂ©enne (climat ensoleillĂ©, chaud et sec; convergence de masses dâair dâhorizons lointains), la pollution de lâair en espĂšces rĂ©actives y est souvent plus forte que dans la plupart de lâEurope continentale. Les changements climatiques (augmentation des sĂ©cheresses et de la tempĂ©rature) et la pression dĂ©mographique devraient dĂ©grader encore la qualitĂ© de lâair. En consĂ©quence, les habitants de la MĂ©diterranĂ©e qui sont dĂ©jĂ rĂ©guliĂšrement soumis Ă des niveaux de pollution bien au-dessus des recommandations de lâOMS devraient se trouver plus exposĂ©s encore, ce qui engendrera une surmortalitĂ©. Un meilleur suivi de lâexposition des habitants et des solutions «gagnant-gagnant» devraient ĂȘtre mises en place dans le but dâamĂ©liorer la qualitĂ© de lâair et de sâengager dans une Ă©conomie dĂ©carbonĂ©e. Les consĂ©quences des changements climatiques sur les Ă©missions de polluants par les principales sources rĂ©gionales ne sont pas toujours trĂšs claires. Il a Ă©tĂ© Ă©tabli que le climat rĂ©gional et le cycle de lâeau sont altĂ©rĂ©s par la chimie de lâatmosphĂšre. En rĂ©duisant le flux solaire en surface, les aĂ©rosols rĂ©duisent les prĂ©cipitations moyennes annuelles de 10% en moyenne sur le bassin mĂ©diterranĂ©en, rĂ©duisant un peu plus une ressource dĂ©jĂ rare. Les aĂ©rosols pourraient rĂ©duire plus encore les prĂ©cipitations en rĂ©duisant la taille des gouttes dâeau dans les nuages ou en agissant sur la formation de cristaux de glaces. Par ailleurs, de rĂ©centes expĂ©riences indiquent que le dĂ©pĂŽt atmosphĂ©rique dâazote et le phosphore issu des poussiĂšres dĂ©sertiques Ă la surface des eaux pauvres en nutriments de la MĂ©diterranĂ©e favorise le dĂ©veloppement du phytoplancton activant par la mĂȘme occasion lâabsorption de CO2 par lâocĂ©an. Cependant, il a aussi Ă©tĂ© observĂ© que le dĂ©pĂŽt de poussiĂšres favorise le dĂ©veloppement de bactĂ©ries qui elles-mĂȘmes rejettent du CO2 du fait de la respiration. Lâeffet net du dĂ©pĂŽt de ces poussiĂšres Ă grande Ă©chelle reste Ă Ă©tablir
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