Note sur les écarts de mesure observés entre les pluviomètres standards et les pluviomètres au sol en Afrique de l'Ouest

En Afrique de l'Ouest, huit sites de mesures étagés de la forêt équatoriale au domaine subsaharien ont permis d'étudier l'écart que l'on observe entre les hauteurs de précipitations interceptées par les pluviomètres standards (bague réceptrice à 1 m au-dessus du sol) et celles arrivant à la surface du sol mesurées à l'aide d'un dispositif éliminant l'influence du vent. Le rapport entre les deux mesures passe de 1 à 2 lorsque l'on se déplace de la forêt dense vers les zones désertiques. Une analyse plus fine de ce phénomène tente d'expliquer cet écart pour chaque événement pluvieux. Comme dans le cas de précédentes études réalisées en Europe, aucun facteur explicatif statistiquement satisfaisant n'a pu être dégagé. (Résumé d'auteur

Rapid, one-pot procedure to synthesise 103Pd:Pd@Au nanoparticles en route for radiosensitisation and radiotherapeutic applications

The radioisotope palladium (103Pd), encapsulated in millimetre-size seed implants, is widely used in prostate cancer brachytherapy. Gold nanoparticles (Au NPs) distributed in the vicinity of 103Pd radioactive implants, strongly enhance the therapeutic dose of radioactive implants (radiosensitisation effect). A new strategy under development to replace millimetre-size implants, consist in injecting radioactive NPs in the affected tissues. The development of 103Pd@Au NPs distributed in the diseased tissue, could increase the uniformity of treatment (compared with massive seeds), while enhancing the radiotherapeutic dose to the cancer cells (through Au-mediated radiosensitisation effect). To achieve this goal, it is necessary to develop a rapid, efficient, one-pot and easy-to-automatise procedure, allowing the synthesis of coreshell Pd@Au NPs. The novel synthesis route proposed here enables the production of Pd@Au NPs in not more than 4h, in aqueous media, with minimal manipulations, and relying on biocompatible and non-toxic molecules. This rapid multi-step process consists of the preparation of ultra-small Pd NPs by chemical reduction of an aqueous solution of H2PdCl4 supplemented with ascorbic acid (AA) as reducing agent and 2, 3-meso-dimercaptosuccinic acid (DMSA) as a capping agent. Pd conversion yields close to 87% were found, indicating the efficiency of the reaction process. Then Pd NPs were used as seeds for the growth of a gold shell (Pd@Au), followed by grafting with polyethylene glycol (PEG) to ensure colloidal stability. Pd@Au-PEG (TEM: 20.2 ± 12.1 nm) formed very stable colloids in saline solution as well as in cell culture medium. The physico-chemical properties of the particles were characterised by FTIR, XPS, and UV-vis. spectroscopies. The viability of PC3 human prostate cancer cells was not affected after a 24-h incubation cycle with Pd@Au-PEG NPs to concentrations up to 4.22 mM Au. Finally, suspensions of Pd@Au-PEG NPs measured in computed tomography (CT) are found to attenuate X-rays more efficiently than commercial Au NPs CT contrast media. A proof-of-concept was performed to demonstrate the possibility synthesise radioactive 103Pd:Pd@Au-PEG NPs. This study reveals the possibility to synthesise Pd@Au NPs rapidly (including radioactive 103Pd:Pd@Au-PEG NPs), and following a methodology that respects all the strict requirements underlying the production of NPs for radiotherapeutic use (rapidity, reaction yield, colloidal stability, NPs concentration, purification)

Experimental study of accelerating field distribution optimization in the H-structure with comb holders

We have suggested to perform the tuning the structure accelerating field distribution at the wave similar to H, by changing the inductivity of the holder of a single drift tube. Changing the angle of bend of the adjacent drift tube holders along different sides relatively to the comb holder plane allows one to increase and decrease the field amplitude in the gap between them. The value Rch ≈90 MОhm/m has been obtained for the structure under consideration that is higher than that obtained by known methods of tuning.Пропонується проводити настройку розподілу прискорюючого поля структури на хвилі, аналогічній Н, зміною індуктивності утримувача одиночної трубки дрейфу. Зміна кута повороту утримувачів сусідніх трубок дрейфу в різні боки щодо площини гребінчастого утримувача дає можливість як збільшувати, так і зменшувати амплітуду поля в зазорі між ними. Для структур, що розглядаються, отримано значення Rш ≈ 90 МОм⋅м⁻¹, що більш, ніж при відомих методах настройки.Предлагается проводить настройку распределения ускоряющего поля структуры на волне, аналогичной Н, изменением индуктивности держателя одиночной трубки дрейфа. Изменение угла поворота держателей соседних трубок дрейфа в разные стороны относительно плоскости гребенчатого держателя дает возможность как увеличивать, так и уменьшать амплитуду поля в зазоре между ними. Для рассматриваемых структур получено значение Rш ≈90 МОм⋅м⁻¹, что больше, чем при известных методах настройки

Governance traditions and narratives of public sector reform in contemporary France.

This article explores the basic traditions of governance in contemporary France and the narratives of public sector reform associated with them. It should be stressed right from the outset that this article does not aim to describe the set of public sector reforms that have been implemented in France in the last ten years or so. Instead, the aim is to demonstrate the similarities and differences between the narratives of the left and the right with regard to these reforms and to show how these narratives help to explain the types of reform that have been enacted. The basic argument is that there is a certain commonality to both the left and the right with regard to their narratives of public sector reform. At the same time, though, there are differences of emphasis both within each tradition and between the two main traditions themselves. Except where indicated, all translations are the author's own