Left Ventricular Pacing In Patients With Congestive Heart Failure

Cardiac resynchronisation therapy (CRT) using biventricular (BIV) pacing has proved its effectiveness to correct myocardial asynchrony and improve clinical status of patients with severe congestive heart failure (CHF) and widened QRS. Despite a different effect on left ventricular electrical dispersion, left univentricular (LV) pacing is able to achieve the same mechanical synchronisation as BIV pacing in experimental studies and in humans. This results in clinical benefits of LV pacing at mid-term follow-up, with significant improvement in functional class, quality of life and exercise tolerance at the same extent as those observed with BIV stimulation in non randomised studies. Furthermore these benefits are obtained at lesser costs and with conventional dual-chamber devices. However, LV pacing has to be compared to BIV pacing in randomised trials before being definitely considered as a cost-effective alternative to BIV pacing

Gisement solaire en France : caractérisation de la ressource énergétique, profil de répartition et volatilité

National audienceEn deux ans (2011-2013), ACOFI a réalisé le financement de plus de 10 MWc en photovoltaïque pour un montant total d'investissement de 50 M€. Ses équipes effectuent régulièrement des travaux de recherche afin de maîtriser les aspects techniques et économiques de la filière ; c'est dans ce sens que nous avons collaboré avec le Centre Observation, Impacts, Energie de MINES ParisTech / ARMINES pour réaliser une étude sur le gisement solaire en France. L'objectif de cette étude est de caractériser le profil de l'ensoleillement en France, en étudiant la répartition annuelle de l'irradiation et sa volatilité interannuelle. Nous reviendrons également sur l'épisode de faible ensoleillement constaté sur l'ensemble de l'Hexagone au cours des premiers mois de l'année 2013

Perceptions and Implementations of Urban Green Infrastructures in France: Three Cases of Studies (Paris, Marseille, Strasbourg)

Green infrastructures have gradually become imperative in planning since the end of 1990s in Europe (Jongman et al, 2004). Numerous urban areas in France mobilize and reinterpret the notion according to stakes of their territory (Blanc, 2012). With the promulgation of Grenelle 1 and 2 Laws (in 2009 and 2010), today every local authorities have to integrate an ecological reflection on green infrastructures into its planning projects at metropolitan and local scales, called “trame verte”. To cover a plurality of contexts of cultural, social, geographical and ecosystematic levels, three cities were retained to understand how this reflection is set up: the municipalities of Paris, Marseille, and Strasbourg. Indeed, in Ile-de-France, a number of initiatives reflect the interest of the regional, departmental and municipal authorities for green infrastructures and biodiversity issues: the Seine St-Denis departmental observatory of biodiversity and natural habitats (City hall of Paris, on 2004), the creation of the regional agency Natureparif (2006), the regional strategy for biodiversity (2007), the Paris biodiversity plan (2011). Furthermore, the city of Marseille, influenced by the example of Barcelona metropolitan area and its anellaverda (green ring), plans the development of a green infrastructure on its municipal territory. It confided the study to the Planning Agency of Marseille Urban area (AGAM) which elaborates scenarios for connecting the residual non-constructed spaces, to endow the city of a green infrastructure addressing the environmental issues of sustainable development. Finally, the region Alsace was one of the first regions to integrate a reflection into these environmental policies on green infrastructure in France (in the late 1990s). The Strasbourg local planning in 1992 and the metropolitan plan in 2007 (SCOTER) mention the term “greenway” in their statutory documents. Currently, as part of the development of the urban local plan (PLU), Strasbourg urban community defines a network of greenways in an ecological perspective. Through the consideration of vegetable continuities in town, the notion of green infrastructures brings a revival in the current urban thinking. If scientists in ecological sciences were interested since a few years in this question to fight against biodiversity erosion, green infrastructures appear as a new field of investigation for human sciences. Multifunctionality associated with this notion of meshing offers new challenges as for practices and perceptions of inhabitants. How decision making can take into account and translate their expectations regarding scientific models proposed and political issues? Its diverse dimensions introduce inevitably new modalities of the public debate organization which remain to invent in most cases today. We have compared in each of the studied sites the three following spheres, often distinct from one another: political, scientific and inhabitants

Validation of three satellite-derived databases of surface solar radiation using measurements performed at 42 stations in Brazil

International audienceThe SoDa website (www.soda-pro.com) is populated with numerous solar-related Web services. Among them, three satellite-derived irradiation databases can be manually or automatically accessed to retrieve radiation values within the geographical coverage of the Meteosat Second Generation (MSG) satellite: the two most advanced versions of the HelioClim-3 database (versions 4 and 5, respectively HC3v4 and HC3v5), and the CAMS radiation service. So far, these databases have been validated against measurements of several stations in Europe and North Africa only. As the quality of such databases depends on the geographical regions and the climates, this paper extends this validation campaign and proposes an extensive comparison on Brazil and global irradiation received on a horizontal surface. Eleven stations from the Brazilian Institute of Space Research (INPE) network offer 1 min observations, and thirty-one stations from the Instituto Nacional de Meteorologia (INMET) network offer hourly observations. The satellite-derived estimates have been compared to the corresponding observations on hourly, daily and monthly basis. The bias relative to the mean of the measurements for HC3v5 is mostly comprised between 1 and 3 %, and that for HC3v4 between 2 and 5 %. These are very satisfactory results and they demonstrate that HC3v5, and to a lesser extent HC3v4, may be used in studies of long-term changes in SSI in Brazil. The situation is not so good with CAMS radiation service for which the relative bias is mostly comprised between 5 and 10 %. For hourly irradiation, the relative RMSE ranges from 15 to 33 %. The correlation coefficient is very large for all stations and the three databases, with an average of 0.96. The three databases reproduce well the hour from hour changes in SSI. The errors show a tendency to increase with the viewing angle of the MSG satellite. They are greater in tropical areas where the relative humidity in the atmosphere is important. It is concluded that except for the overestimation by CAMS radiation service, the three databases are suitable for studies of the solar resources in Brazil

Validation of HelioClim-3 version 4, HelioClim-3 version 5 and MACC-RAD using 14 BSRN stations

International audienceThis communication presents the results of a comparison of three satellite-derived databases covering Africa, Europe, Middle East and part of South America, against corresponding 15 min irradiations of very high quality measured by fourteen Baseline Surface Radiation Network (BSRN) stations. The three databases are accessible via the SoDa Service website, and are the two latest versions of HelioClim-3: versions 4 (HC3v4) and 5 (HC3v5), and the MACC-RAD database. The comparison was performed for durations of 15 min, 1 h, 1 day and 1 month for both the global irradiation received on a horizontal surface (GHI) and the direct irradiation received on a plane normal to sun rays (DNI). It is found that the three satellite-derived radiation databases exhibit satisfactory performances. For most of the fourteen locations, HC3v5 surpasses HC3v4 and MACC-RAD, with a bias ranging from-4 to 5% for the GHI and for all tested duration. The correlation coefficient is large for all databases and most often greater than 0.92 for 15 min and 0.98 for daily irradiation for GHI. The RMSE is fairly constant for all locations for 15 min and is approximately 20 kWh m-2 –slightly greater for MACC-RAD.-For daily irradiation, it ranges between 300 and 400 kWh m-2 for HC3v5, 300 and 500 kWh m-2 for HC3v4, and 400 and 550 kWh m-2 for MACC-RAD. Bias for the DNI is larger in absolute values than for GHI for all databases:-12 to 10% for HC3v5. The correlation coefficient is most often greater than 0.68 for 15 min and 0.84 for daily irradiation. The RMSE for 15 min ranges between 46 and 60 kWh m-2 for HC3v5, 46 and 63 kWh m-2 for HC3v4, and 48 and 66 kWh m-2 for MACC-RAD. For daily irradiation, it ranges between 1100 and 1600 kWh m-2 for HC3v5, between 1300 and 1700 kWh m-2 for HC3v4, and between 1000 and 1850 kWh m-2 for MACC-RAD. The MACC-RAD resource show promises provided the model for cloud properties is improved

The Solar Forecast Similarity Method: a new method to compute solar radiation forecasts for the next day

International audienceThe need for PV plant owners to plan what they are injecting in the electricity grid is more and more stringent to avoid endangering the whole supply in electricity. A new solar forecast algorithm, named Solar Forecast Similarity Method, has been developed to predict irradiance for the next day based on a statistical study of the long term HelioClim-3 irradiation database. This algorithm searches in the past for the most similar days compared to the day of interest and uses their following days to produce a forecast. The model has been optimized against the database itself to compute the most adequate set of parameters over France and for the month of January 2014. With this configuration, the results are a null bias and a root mean square error of 48%. The algorithm outperforms the persistence by 20% and the error is similar to existing methods. An objective validation has then been carried out to compare the irradiance forecasts to high quality measurements from several Baseline Surface Radiation Network (BSRN) ground stations. The method is very promising since the comparison results are in line or lower than the one obtained with the first validation analysis performed on the HelioClim-3 database. For high frequencies, however, predictions have a high error for rapidly varying weather. This demonstrates that the method provides information for the averaged production the following day but requires another input to reliably predict high frequency irradiance