850 research outputs found

    Non-singular, vacuum, stationary space-times with a negative cosmological constant

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    We construct infinite dimensional families of non-singular stationary space times, solutions of the vacuum Einstein equations with a negative cosmological constant.Comment: minor corrections, an inessential uniqueness claim withdraw

    L’évaluation des politiques en relations internationales : Le cas de la coopération franco-québécois en éducation

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    Taking into account recent policy analysis and evaluation theories which have been rarely applied international relations up till now, we attempted to construct a framework which we used to evaluate France-Quebec policies of cooperation in the field of education. Having identified the objectives of this cooperation, we verified wether these objectives were attained through the programme of integrated projects in education. Concerning the objective of creating international links it appears that it was realized when the programme was elaborated; however, the programme increases and officializes the exchanges, without that the Federal government intervenes, and leaves to the Quebec government the ability to impose its priorities. The integrated projects do not balance American influence, as it was the intention. The objectif of promotion of French language is partially realized through the publication of articles in French or the Frenchization of the bibliographies ; but the programme results in a perverse effect when French and Quebecer researchers publish jointly in English. The academic cooperation did not favorize teaching improvement of Quebecer professors, as it was an objective; however, it favorized research development. The results were partially attained, because this policy began without any study of the situation

    Characterization of reciprocity gaps from interference tests in fractured media through a dual porosity model

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    We analyze drawdown reciprocity gaps emerging in interference tests performed in a confined fissured karstic formation. Modeling the system as a dual porosity continuum allows characterizing the dynamics of the relative contribution of the connected fractures and the rock matrix to the total flow rate extracted at the pumping wells. Observed lack of reciprocity of drawdowns can then be linked to the occurrence of processes that are not accounted for in the classical flow models based on a single-continuum representation of the system through flow equations grounded on Darcy's law only. We show that interpreting the system as a dual porosity continuum can cause drawdown reciprocity gaps to emerge as a consequence of local effects associated with an identifiable contribution of the matrix to the total fluid extracted at the well location during pumping. These theoretical results are then employed to identify the contribution to the flow being supplied to the pumping well by the low conductivity matrix constituting the host rock formation, in contrast to that provided by the fractures. An application to data from two interference tests performed at the Hydrogeological Experimental Site (HES) in Poitiers, France, illustrates the approach. We show that, whenever the matrix is assumed to provide a contribution to the total flow rate extracted, nonreciprocity is expected, the latter being linked to the occurrence of a differential drawdown between fracture and matrix at the pumping well. This difference decreases with time in the example presented, displaying a power law late time behavior, with nonreciprocity effects persisting up to remarkably long times

    Mutation du foncier agricole en frange urbaine : élaboration et mise à l'épreuve d'une politique de régulation territoriale

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    International audienceLe pôle urbain de Montpellier s'est largement étalé lors des dernières décennies à la faveur de son dynamisme démographique et du retrait de la viticulture : la " maîtrise " communale de l'urbanisme s'est traduite par une urbanisation tous azimuts. Comment mettre fin à ces processus sans compromettre l'économie résidentielle ? C'est une priorité de la nouvelle intercommunalité dont la politique d'aménagement est analysée. La genèse de cette politique est retracée ainsi que sa traduction dans le schéma de cohérence territoriale, dont les objectifs d'économie d'espace et les outils - identification des limites, densification, maîtrise foncière - sont détaillés. Sa mise en ½uvre au niveau communal révèle les forces et les faiblesses de cette politique. Cette étude empirique soutient une réflexion plus générale sur les dynamiques foncières périurbaines et les outils politiques de régulation, à la croisée des problématiques de gouvernance territoriale et de préservation des ressources

    What is required to end the AIDS epidemic as a public health threat by 2030? The cost and impact of the fast-track approach

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    In 2011 a new Investment Framework was proposed that described how the scale-up of key HIV interventions could dramatically reduce new HIV infections and AIDS-related deaths in low and middle income countries by 2015. This framework included ambitious coverage goals for prevention and treatment services for 2015, resulting in a reduction of new HIV infections by more than half, in line with the goals of the declaration of the UN High Level Meeting in June 2011. However, the approach suggested a leveling in the number of new infections at about 1 million annually-far from the UNAIDS goal of ending AIDS by 2030. In response, UNAIDS has developed the Fast-Track approach that is intended to provide a roadmap to the actions required to achieve this goal. The Fast-Track approach is predicated on a rapid scale-up of focused, effective prevention and treatment services over the next 5 years and then maintaining a high level of programme implementation until 2030. Fast-Track aims to reduce new infections and AIDS-related deaths by 90% from 2010 to 2030 and proposes a set of biomedical, behavioral and enabling intervention targets for 2020 and 2030 to achieve that goal, including the rapid scale-up initiative for antiretroviral treatment known as 90-90-90. Compared to a counterfactual scenario of constant coverage for all services at early-2015 levels, the Fast-Track approach would avert 18 million HIV infections and 11 million deaths from 2016 to 2030 globally. This paper describes the analysis that produced these targets and the estimated resources needed to achieve them in low- and middle-income countries. It indicates that it is possible to achieve these goals with a significant push to achieve rapid scale-up of key interventions between now and 2020. The annual resources required from all sources would rise to US7.4Bninlowincomecountries,US7.4Bn in low-income countries, US8.2Bn in lower middle-income countries and US$10.5Bn in upper-middle-income-countries by 2020 before declining approximately 9% by 2030

    First inappropriate implantable cardioverter defibrillator therapy is often due to inaccurate device programming: analysis of the French OPERA registry

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    AIMS:Inappropriate therapy delivered by implantable cardioverter defibrillators (ICDs) remains a challenge. The OPERA registry measured the times to, and studied the determinants of, first appropriate (FAT) and inappropriate (FIT) therapies delivered by single-, dual- and triple-chamber [cardiac resynchronization therapy defibrillator (CRT-D)] ICD. METHODS AND RESULTS: We entered 636 patients (mean age = 62.0 ± 13.5 years; 88% men) in the registry, of whom 251 received single-, 238 dual-, and 147 triple-chamber ICD, for primary (30.5%) or secondary (69.5%) indications. We measured times to FAT and FIT as a function of multiple clinical characteristics, examined the effects of various algorithm components on the likelihood of FAT and FIT delivery, and searched for predictors of FAT and FIT. Over 22.8 ± 8.8 months of observation, 184 patients (28.9%) received FAT and 70 (11.0%) received FIT. Ventricular tachycardia (VT) was the trigger of 88% of FAT, and supraventricular tachycardia was the trigger of 91% of FIT. The median times to FIT (90 days; range 49-258) and FAT (171 days; 50-363) were similar. The rate of FAT was higher (P <0.001) in patients treated for secondary than primary indications, while that of FIT were similar in both groups. Out of 57 analysable FIT, 27 (47.4%) could have been prevented by fine tuning the device programming like the sustained rate duration or the VT discrimination algorithm. CONCLUSIONS: First inappropriate therapy occurred in 11% of 636 ICD recipients followed for ∼2 years. Nearly 50% of FIT could have been prevented by improving device programming

    Gefäßchirurgische Ausbildung in endovaskulärer Technik in Lausanne

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    Zusammenfassung: Zwischen 1995 und 2005 wuchs die Anzahl der jährlich von uns mit endovaskulären Techniken versorgten Aortenaneurysmen (EVAR) von 0 auf 50, und dies auf allen Stufen der Aorta. Zu unserer Organisation gehören ein breites Team von Chirurgen, ein Lager mit 3kompletten Familien von Endoprothesen (gerade Endoprothesen, konische Endoprothesen, und Bifurkationen), ein mobiler Wagen mit Zubehör (Einführungsbestecke, Führungsdrähte, Katheter, Ballone etc.) und ein Apparat auf Rädern für die intravaskuläre Ultraschalluntersuchung (IVUS). Letzterer erlaubt es zusammen mit einer mobilen Durchleuchtungsanlage (C-Bogen), in jedem Operationssaal unserer Institution endovaskulär Aneurysmen zu analysieren, und dies in der Regel ohne Angiographie bzw. Kontrastmittel. Deshalb sind wir nicht mehr auf eine ausgiebige bildgebende präoperative Abklärung potenzieller Kandidaten für eine endovaskuläre Sanierung von Aneurysmen angewiesen und können rupturierte Aneurysmen der Bauchaorta oder der thorakalen Aorta ohne Verzug behandeln. Bei der endovaskulären Sanierung von Aortenaneurysmen unterscheiden wir zwischen Prozessschritten (Indikationsstellung, Darstellung der Zugangsgefäße, Ausmessen mittels IVUS und Roadmapping mittels Durchleuchtung, Implantatwahl, Implantatinsertion, Positionierung, Implantatabwurf, Erfolgsbeurteilung, Rekonstruktion der Zugangsgefäße und Nachkontrolle) und Kompetenzstufen (Assistent, Oberarzt, Leitender Arzt). Unsere ultraschallgestützte Technik zur endovaskulären Sanierung von Aneurysmen wurde mittels IVUS-Transporter und Telementoring erfolgreich auch anderen Institutionen zur Verfügung gestell
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