901 research outputs found
Education supply, economic growth and the dynamic of skills
This paper examines the dynamics of the skill supply and its incidence on economic growth in the presence of education policies. When there are indivisibilities in the financing of human capital, small differences in the initial distribution of skills may greatly affect the stationary distribution : the economy may end up in a "low skill trap", or in a high skill equilibrium. The model implies that for some ranges of initial distributions there will be intergenerational immobility. Finally, cross-country différences in long-term macroeconomic adjustment to education policies may be attributed, among other factors, to the existence of a congestion effect in the education System.Groth, Education, Human capital, Social mobility
Particle flux in the Rainbow hydrothermal vent field (Mid-Atlantic Ridge): Dynamics, mineral and biological composition
In order to provide information about the export and the distribution of hydrothermal particulate material to the surrounding deep ocean, four moorings were deployed in the vicinity of the hydrothermal Rainbow vent field (Mid-Atlantic Ridge, 36°14′N, 2250 m depth). The first mooring was a sediment trap with a current meter deployed at 2 m from a chimney of the Rainbow vent field and 1.5 m above the bottom (a.b.) for 16 days. It represented the reference for the initial composition of particles produced by the vent. The total mean mass particle flux (6.9 g m-2 d-1) was distinctly higher than the flux measured at the shallower hydrothermal vents on the MAR segment. This particulate flux showed a high temporal variation at the scale of a few days and was characterized by a high concentration of sulphur (17.2%) and copper (3.5%) and a very low concentration of organic carbon (0.14%). Several hundred bivalve larvae belonging to the hydrothermal mytilid Bathymodiolus azoricus were collected in this trap at the beginning of the experiment. The density of larvae decreased strongly at the end, indicating a patchiness distribution or a discontinuous reproduction of this species. The other three moorings, including sediment traps, current-meters and thermistor chains, were deployed for 304 days at different distances and altitudes from the Rainbow vent field. The mean speed of the current in the rift valley was low (6 cm s-1) and was oriented toward the north. The total mean particle mass flux measured with the five sediment traps varied little, from 10.6 to 25.0 mg m m-2 d-1, and displayed temporal variations which are typical of deep-sea environments with seasonal changes in the overlying production. However, in the trap at 500 m from the vents 150 m a.b., the presence of the hydrothermal plume can be observed: the sulphur, iron and copper concentrations of particles were significantly higher compared to the particles sampled in the pelagic reference trap. The plume composition was about 50% hydrothermal particles and 50% pelagic particles and its upper limit reached 300 m a.b. at this distance. In the traps at 1000 m from the vents, the elemental composition of particles was similar to the pelagic particles and we assume that these traps were not in the plume during the experiment. The zooplankton obtained in the long-term trap samples revealed high density variations in relation to the distance from the vent site. The nutrient enrichment around the hydrothermal area and the abundance of free living bacteria explain these variations in zooplankton density
The DIDAM framework Disaggregated demand and assignment models for combined passengers and freight transport
The objective of this paper is to present the methodological developments in the DIDAM (Disaggregated demand and assignment models for combined passengers and freight transport) research project, which aims at advancing fundamental research in transportation modelling and analysis, using two complementary methodologies. The first is to develop a joint methodological approach for both freight and passenger transport, and the second is to base this common approach on the use of models that are as disaggregate and realistic as possible. Furthermore, the methods will be designed to cope with the important question of competition for infrastructure. The project is mainly organized around two themes. Each of them covers both freight and passengers aspects, in a manner which promotes collaborative work between the partners of the project. The first theme is concerned with disaggregate demand modelling issues, the second deals with innovative aspects of (joint) traffic assignment. Working at a fully disaggregate level is however not always easy. If such models are already available for passenger demand and traffic, disaggregate tools are still largely missing for freight transport. This is not only true at the operational level, but, more crucially, at the conceptual level. This is why our research program adopts, in this domain, a progressive approach that introduces disaggregation gradually into existing methods and models. This entails research in a full spectrum of issues, ranging from concepts definition (who are the actors, how can they be characterized ...) to validation exercises using available data source
y a-t-il une place pour la radiothérapie en fin de vie ?
peer reviewedPrès de 50 % des patients atteints d’un cancer bénéficient, à un moment de leur trajet de soins, d’une irradiation. Celle-ci peut être administrée avec une intention curative ou palliative, en fonction de l’extension de la maladie, de l’état général du patient et de sa volonté. Le but d’une irradiation palliative, sera de contrôler localement la tumeur ou la métastase et, donc, de ralentir l’évolution du cancer. La radiothérapie peut également être utile pour supprimer un symptôme et, ainsi, être un des traitements de confort en fin de vie. La dose totale, la dose par fraction ainsi que la technique d’irradiation sont adaptées à l’intention du traitement. Cet article passe en revue les principales indications d’irradiation en fin de vie
0304: How long should we keep a temporary pace maker after transcatheter aortic valve replacement (TAVR)
A temporary pace-maker (TPM) is often used after TAVR due to the risk of atrioventricular block (AVB) in the following days, related to progressive conduction system injuries. However guidelines are unclear as when to safely remove it. Between 2013 and 2014, 195 patients without previous permanent pacemaker, were prospectively followed after TAVR (69 Edwards Sapiens (ES) and 126 CoreValve (CV)). 47 had preoperative bundle branch block, 23 left (LBBB), 24 right sided (RBBB). Peri-operative high degree AVB was noted in 37 patients (20%). 24 were transient, less than 10mn and; 13 persisted at the end of the procedure and were implanted with a permanent pace-maker. New LBBB was observed in 55 patients (28%). In the post-operative period, 23 patients (13%) developped AVB (20 patients within 5 days, and 3 patients after 7 days) (4 ES and 19 CV). No new AV block had occurred at one month in the remaining population. Risk factors for late AVB were peri-operative transient AVB (40%), post-operative RBBB (30%), or LBBB (20%); preexistent RBBB and Corevalve model. Conversely 41 of the 42 patients without AVB or bundle branch block did not need temporary pacing in the post operative time. The only patient without any perioperative event who developed a late AV block at day 7 had a CV inserted in an old surgical valve. However, sinus dysfunction occurred in 2 patients treated with amiodarone for atrial fibrillation in the post operative period, needing temporary pacing. Conclusion: The use of TPM after TAVR is common for the management of delayed high degree AVB. The main risk factors are peri-operative AVB and post-operative BBB. Most of delayed AVB occur within 5 days. Later AVB preceded by prolonged PR interval and BBB should increase the length of TPM. However, in the absence of these factors TPM could be shortened.Abstract 0304 – Figure: Time occurence of AVB (CV=Corevalve, ES=Sapien
034 High doses of clopidogrel to overcome genetic resistance: the randomized cross-over CLOVIS-2 study
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