274 research outputs found

    Interactions between the Somali Current eddies during the summer monsoon: insights from a numerical study

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    International audienceThree hindcast simulations of the global ocean circulation differing by resolution (1/4 or 1/12°) or parametrization or atmospheric forcing are used to describe the interactions between the large anticyclonic eddies generated by the Somali Current system during the Southwest Monsoon. The present investigation of the Somalian coherent eddy structures allows us to identify the origin and the subsequent development of the cyclones flanked upon the Great Whirl (GW) previously identified by Beal and Dono-hue (2013) in satellite observations and to establish that similar cyclones are also flanked upon the Southern Gyre (SG). These cyclones are identified as potential actors in mixing water masses within the large eddies and offshore the coast of Somalia. All three simulations bring to light that during the period when the Southwest Monsoon is well established, the SG moves northward along the Somali coast and encounters the GW. The interaction between the SG and the GW is a collision without merging, in a way that has not been described in observations up to now. During the collision the GW is pushed to the east of Socotra Island, sheds several smaller patches of anticyclonic vorticity, and often reforms into the Socotra Eddy, thus proposing a formation mechanism for that eddy. During this process the GW gives up its place to the SG. This process is robust throughout the three simulations

    Somalie

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    Daraasaad la sameeyey 1966 oo ku saabsan sidii ay ku suurtaggeli lahayd warshadaynta dalka Soomaaliya iyo diraasaad dhaqaale oo halkaas lagu qoondaynayo mashaariic.Studio sulle possibilità di industrializzazione della Somalia effettuato nel 1966 e studio economico dei progetti in essere.A study on the possibilities of industrialization of Somalia carried out in 1966 and an economic study of the projects in place.Link:http://aei.pitt.edu/34949/1/A1100.pd

    Ro-vibrational analysis of the XUV photodissociation of HeH+^+ ions

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    We investigate the dynamics of the photodissociation of the hydrohelium cation HeH+^+ by XUV radiation with the aim to establish a detailed comparison with a recent experimental work carried out at the FLASH free electron laser using both vibrationally hot and cold ions. As shown in previous theoretical works, the comparison is hindered by the fact that the experimental ro-vibrational distribution of the ions is unknown. We determine this distribution using a dissociative charge transfer set-up and the same source conditions as in the FLASH experiment. Using a non-adiabatic time-dependent wave packet method, we calculate the partial photodissociation cross sections for the n=1−3n=1-3 coupled electronic states of HeH+^+. We find a good agreement with the experiment for the total cross section into the He + H+^+ dissociative channel. By performing an adiabatic calculation involving the n=4n=4 states, we then show that the experimental observation of the importance of the electronic states with n>3n>3 cannot be well explained theoretically, especially for cold (v=0v=0) ions. We also calculate the relative contributions to the cross section of the Σ\Sigma and Π\Pi states. The agreement with the experiment is excellent for the He+^+ + H channel, but only qualitative for the He + H+^+ channel. We discuss the factors that could explain the remaining discrepancies between theory and experiment.Comment: 10 pages, 8 figure

    Highly relaxing gadolinium based MRI contrast agents responsive to Mg2+ sensing

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    [Abstract] A Gd complex based on a polyphosphonated pyridyl ligand shows a very high stability in aqueous solution (logKEuL = 25.7), a high relaxivity (8.5 mM−1 s−1 at 25 °C and 20 MHz) and a marked and selective relaxivity enhancement (37%) in the presence of Mg2+, opening interesting perspectives for the design of cation responsive contrast agents
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