816 research outputs found
An Analysis of the Mortality Risks Associated with Heat and Heat Waves in Ireland, to Assist in Planning for Climate Change
Although extreme temperatures have not been identified as a major cause of mortality in Ireland, climate change calls for an evaluation of the past, present and future health risks associated with heat and heat waves. The health impacts of heat were investigated using mortality and temperature data for the period 1981-2003. Data were aggregated in urban areas (Dublin, Cork, Drogheda, Arklow, Dundalk, Galway, Limerick, Waterford and Wexford) and rural areas. Seven heat waves were identified between 1981 and 2003, corresponding to 254 excess deaths (197 in rural areas, and 57 in urban areas). A major episode was observed in rural areas in 1983: +115 [confidence interval CI 95% 96:137] extra deaths between the 5th and the 23rd July 1983. During summer, a 1°C increase above 15°C in the mean temperature was associated with a 1.5% [CI 95% 0.9:2.1] increase in total mortality in rural areas, and a 1.6% [0.6:2.5] increase in total mortality in urban areas. Risks were modified by the mortality observed in the preceding winter. There are indications that the heat-related risks have been decreasing between the 80s and the 90s. A better geographical resolution of the mortality data is an asset to refine this analysis and to study any relationship between a health topic and an environmental exposure. Despite limits on the data, an increase in temperature was associated with an increase in mortality during summer in Ireland, and past heat waves were associated with a small but observable excess mortality. With the perspective of climate change, and with the ageing of the population, it may be that more severe heat episodes results in a larger mortality burden, as was observed during the July 1983 heat wave. Steps to reduce vulnerability to heat during extreme episodes should be considered
Potentialities of the sol-gel route to develop cathode and electrolyte thick layers Application to SOFC systems
In this work, we report the potential of sol–gel process to prepare cathode and electrolyte thin and thick layers on anodic NiO-YSZ supports which were also made from powders prepared by sol–gel route. YSZ and La2 − xNiO4 + δ, La4Ni3O10 were synthesized as electrolyte and cathode materials for SOFC applications. For electrolyte shaping, yttria stabilized zirconia (YSZ, 8% Y2O3) thick films were cast onto porous NiO-YSZ composite substrates by a dip-coating process using a new suspension formulation. Part of the YSZ precursor colloidal sol was added in the suspension to ensure both homogeneity and adhesion of the electrolyte on the anodic substrate after thermal treatment at 1400 °C for 2 h. By precisely controlling the synthesis parameters, dense and gas-tight layers with thicknesses in the range of 10–20 μm have been obtained. Gas-tightness was confirmed by He permeation measurements. Concerning cathode processing, a duplex microstructured cathode consisting of both La2 − xNiO4 + δ ultra-thin films (few nanometers) and La2 − xNiO4 + δ and/or La4Ni3O10 thick layers (few micrometers) was prepared on YSZ substrates by the dip-coating process, with the thickness being dependent on the nature of the dip-coated solution (polymeric sol or adequate suspension). The derived cathode microstructure, related to the number/thickness of layers and type of architecture, was correlated to the good cell electrochemical performances. Concerning cathode processing, a duplex microstructured cathode consisting of both La2 ? xNiO4 + ? ultra-thin films (few nanometers) and La2 ? xNiO4 + ? and/or La4Ni3O10 thick layers (few micrometers) was prepared on YSZ substrates by the dip-coating process, with the thickness being dependent on the nature of the dip-coated solution (polymeric sol or adequate suspension). The derived cathode microstructure, related to the number/thickness of layers and type of architecture, was correlated to the good cell electrochemical performances
Development of lanthanum nickelate as a cathode for use in intermediate temperature solid oxide fuel cells
The performance of lanthanum nickelate, La2NiO4+δ (LNO), as a cathode in IT-SOFCs with the electrolyte cerium gadolinium oxide, Ce0.9Gd0.1O2−δ (CGO), has been investigated by AC impedance spectroscopy of symmetrical cells. A significant reduction in the area specific resistance (ASR) has been achieved with a layered cathode structure consisting of a thin compact LNO layer between the dense electrolyte and porous electrode. This decrease in ASR is believed to be a result of contact at the electrolyte/cathode boundary enhancing the oxygen ion transfer to the electrolyte. An ASR of 1.0 Ω cm2 at 700 °C was measured in a symmetrical cell with this layered structure, compared to an ASR of 7.4 Ω cm2 in a cell without the compact layer. In addition, further improvements were observed by enhancing the cell current collection and it is anticipated that a symmetrical cell consisting of a layered structure with adequate current collection would lower these ASR values further
Elaboration of metallic compacts with high porosity for mechanical supports of SOFC
The development of third generation Solid Oxide Fuel Cells (SOFC) with metallic mechanical supports presents several advantages over that of ceramic stacks by offering a lower cost and longer lifetime of the stacks. As a consequence, it is necessary to prepare metallic porous compacts that remain stable at the operating temperature of the SOFC (700–800 C) under reductive atmosphere. This paper presents an innovative process to elaborate iron, nickel and cobalt porous compacts. The process is based on the thermal decomposition of metal oxalate precursors with controlled morphology into metallic powders with coralline shape. Uniaxial compaction of such powders (without binder addition to the powders) under low uniaxial pressures (rising from 20 to 100 MPa) gave rise to green compacts with high porosity and good mechanical properties. After annealing at 800 C under H2 atmosphere, the compacts still present interconnected porosity high enough to allow sufficient gas flow to feed a SOFC single cell in hydrogen: the porosity rises from 25 to 50% for iron compacts, from 20 to 50% for cobalt compacts, and is higher than 40% for nickel compacts. Results from physicochemical characterization (XRD, SEM, gas permeation, Hg porosimetry) corroborated the process for SOFC application
A new route to prepare anodic coatings on dense and porous metallic supports for SOFC application
Metallic cell supports have been developed for the new generation of fuel cells. Sol–gel process has been used to prepare anodic coatings on these supports at moderate thermal treatment temperature, in order to keep a good support mechanical behavior and limit metallic corrosion. Indeed, we take advantage of the numerous reaction routes that sol–gel method can offer to first synthesize NiO–YSZ (yttria-stabilized zirconia) homogeneous composites, and then to process films of different thicknesses on metallic supports by dipcoating. In this work, the metallic supports could be either dense or porous. To begin with, duplex microstructured anodes were prepared from both thin and thick layers, directly deposited on dense metallic supports. The interfacial anodic layer, around 100 nm thick, improves adhesion and accommodates stresses between metallic interconnect and active thick anode. Moreover, by dipping the substrate into an optimized slurry containing sol–gel composite powders, films of a few microns thick have been obtained and constituted the active anodic part. A heat treatment at only 800 °C leads to a coherent anodic duplex stacking which is continuous, homogeneous and adherent. Subsequently, thick anodic films have also been deposited on two different porous supports, with both dip-coating process and slurries routes. These thick anodic coatings were characterized after thermal treatment at 800 °C
Parcours spécifiques : allier réussite et contraintes individuelles
Comprend des références bibliographiquesDepuis plus de douze ans, une structure spéciale et efficace a été mise en place au sein de l’Institut Universitaire de Technologie 1 de Grenoble afin d’accueillir et d’accompagner les nombreux étudiants ayant des contraintes fortes dans le déroulement de leurs études. Celle-ci propose des adaptations pour tous types de contraintes individuelles et repose sur une équipe de correspondants et de tuteurs dans chaque département d’enseignement. Les taux de réussite obtenus sont les mêmes que ceux des étudiants n’ayant pas de contraintes particulières ce qui prouve que la compensation des contraintes est bien effectuée. Cependant, les restrictions budgétaires actuelles risquent de remettre en cause ces adaptations bien qu’elles soient peu onéreuses
Le giroflier à Madagascar : essai d’histoire et de géographie coloniales, 1896-1958
Madagascar est aujourd’hui le second producteur mondial après l’Indonésie et premier exportateur mondial de clous et d’essence de girofle. Le giroflier a été introduit à Madagascar il y environ deux siècles mais le contexte de son introduction et de son expansion a été peu étudié et de nombreuses questions relatives aux conditions de production et de commercialisation durant la période coloniale et postcoloniale restent encore en suspens. En croisant les données recueillies dans le Journal Officiel de Madagascar et Dépendances, publié entre 1896 et 1958, et les écrits d’ingénieurs agronomes et d’administrateurs coloniaux, l’objectif de cet article est de dresser un tableau géographique et historique de l’évolution de la filière du giroflier à Madagascar. Géographique tout d’abord en esquissant les modalités d’expansion des plantations qui, si elles semblent au premier abord s’étendre de manière graduelle depuis l’île de Sainte-Marie vers la côte est de Madagascar, répondent en réalité à une implantation au « coup par coup » dont les modalités sont liées à des facteurs physiques (sol, climat, proximité de voies de communication fluviales ou terrestres) mais aussi et surtout à des conditions matérielles et humaines spécifiques. L’étude des sources recueillies permet ainsi d’esquisser l’évolution géographique de ces implantations durant la première moitié du XXe siècle et l’essor des ateliers de distillation des feuilles et griffes de girofle qui se multiplient à partir des années 1920. Historique, ensuite, par l’étude de l’action de l’Administration coloniale pour favoriser et encadrer une production qui, avec les autres cultures dites « riches » (café, cacao, vanille, plantes à parfum) doit permettre à la colonie d’établir une balance commerciale équilibrée. Sur fond de lutte impériale avec les productions britanniques des îles de Zanzibar et de Pemba, alors premier producteur mondial de clous de girofle au début du siècle, l’Administration encourage les colons mais également les Malgaches à adopter cette culture. Le giroflier devient dès lors un symbole incontournable de l’île de Sainte-Marie puis de la côte est de la Grande-Île. En parallèle, les administrateurs mènent une politique active de publicité auprès des consommateurs métropolitains tout en promouvant la recherche de débouchés transversaux : production d’eugénol pour la pharmacologie, mise en relation producteurs et importateurs, accords commerciaux avec des pays étrangers, etc. En privilégiant cette approche historico-géographique, cette article espère apporter des clés de lecture permettant de comprendre l’adoption et le développement de cette culture à Madagascar, d’apporter des éléments de compréhension de son évolution actuelle et, par la même occasion d’en envisager l’avenir.Madagascar, the world’s second largest producer of cloves, has experienced a drop in production because of the ageing of its productive tree stock. The reduced productivity of this resource has prompted a joint study and broad reflection about its future and its past origins. Initiated by the International Development and Agronomic Research Center (CIRAD) and the local universities of Madagascar, this multidisciplinary research should help the local clove industry better understand changes in the international market critical to Madagascar’s clove exports and foreign exchange earnings. The introduction of non-endemic clove trees to Madagascar and the expansion of their production have not previously been widely studied and several key questions regarding the conditions of production and the marketing sales strategy during both the colonial and post-colonial periods remain unanswered. By looking at data collected from the Journal Officiel de Madagascar et Depandances, published between 1896 and 1958, and written statements by agronomists and colonial civil servants (eg. Raymond Decary, Emile Prudhomme and Edmond Francois) this paper lays out a geographical and historical perspective of the evolution of the clove industry in Madagascar. First, the geographic evolution is outlined. Based on a review of the source data and literature, there was a gradual expansion of clove plantations from the area l’Ile de Sainte Marie towards the eastern coast of Madagascar during the first half of the 20th century. The expansion occurred in small, unplanned steps influenced by a combination of physical factors (soil, climate, and proximity to river or overland transport) and by specific entrepreneurial and marketability factors (access to finance until the first harvests, availability of farm labor, and good physical infrastructure to enable exports). Beginning in about the 1920s, small-scale clove distilleries first appeared and grew in a scattered fashion around the coastal areas. The historical evolution of clove production can be studied through papers written during the colonial period. French colonial administrators in Madagascar encouraged the production of marketable, export-earning crops, known as “rich crops”, such as cloves, coffee, chocolate, vanilla, and plants for the perfume industry. The objective was to enable the colony to have a favorable trade balance. The strategy was also part of a colonial rivalry with the British colonies producing similar crops in the islands of Zanzibar and Pemba located off the coast of Tanzania. At that time (1900), Tanzania was the largest world producer of cloves and the French colonial administration wanted to encourage French colonial and local Madagascar farmers to introduce this crop which was rapidly to become a defining symbol of l’Ile de Ste Marie and the Eastern Coast. In parallel, the colonial administration put producers in direct contact with importers and prepared commercial agreements. It also spearheaded an active marketing campaign in French cities to incorporate cloves into daily consumption habits and worked to identify opportunities for using clove extract (eugenol) in the pharmaceutical industry. By using an historical and geographic approach, this paper tries to understand the past development and growth of this industry and garner insights into its future prospects
Surveillance of gastrointestinal disease in France using drug sales data
AbstractDrug sales data have increasingly been used for disease surveillance during recent years. Our objective was to assess the value of drug sales data as an operational early detection tool for gastroenteritis epidemics at national and regional level in France. For the period 2008–2013, we compared temporal trends of drug sales for the treatment of gastroenteritis with trends of cases reported by a Sentinel Network of general practitioners. We benchmarked detection models to select the one with the best sensitivity, false alert proportion and timeliness, and developed a prospective framework to assess the operational performance of the system. Drug sales data allowed the detection of seasonal gastrointestinal epidemics occurring in winter with a distinction between prescribed and non-prescribed drugs. Sales of non-prescribed drugs allowed epidemic detection on average 2.25 weeks earlier than Sentinel data. These results confirm the value of drug sales data for real-time monitoring of gastroenteritis epidemic activity
Hedges and Woody Strips Browsing by Cattle on Pasture in Wallonia, Belgium
Shrub and tree forages are commonly used in animal production in many regions of the world. Nonetheless, in Western Europe, and especially in Wallonia in Belgium, hedges and woody strips have disappeared from the agricultural landscape over the past 60 years. Browse species are usually rich in plant secondary compounds such as tannins whose benefits on CH4 production and intestinal parasitism have been highlighted (Ramírez-Restrepo et al. 2010). Currently, agri-environmental measures taken by the Walloon government promote hedges and woody strips in pastures, raising the interest in browse species functionalities in ruminant production.
This study aimed at: (1) determining the influence of the access to a hedge on the behaviour of cattle on pasture; and (2) evaluating the fermentability by rumen microbes of foliage of woody species promoted in the Walloon landscape
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