246 research outputs found

    L'urbanisme au début du siècle : de la réforme urbaine à la compétence technique

    Get PDF
    co-écrit avec Viviane ClaudeInternational audienceDepuis le début du XXème siècle, ceux qui se sont appelés, en France, les "urbanistes" ont revendiqué un pouvoir croissant en matière de maîtrise des villes. Des recherches menées au cours de ces quinze dernières années on peut tirer deux facteurs éclairant leur rôle : le contexte historique du premier quart de siècle où les milieux réformateurs occidentaux tentent d'ériger la ville en "question"; les effets produits par la première législation française sur la planification urbaine et la désignation de "l'homme de l'art" à laquelle elle procède. Autour de ces deux ensembles se trame le débat entre l'Urbanisme à majuscule, comme cause et combat de la réforme urbaine, et l'urbanisme à minuscule, comme technique et ensemble de règles.−−−−−Since the beginning of the 20 th century, those who, in France, called themselves "urbanistes" have claimed responsability and power on the control of cities. The scholarship of the last 15 years shed light on two aspects that can explain the fate of this profession: the historical context of the years 1900-1925, when reformers all over the Western World try to construct the city as a "question"; the consequences of the first french legislation on urban planning and of the included designation of the "homme de l'art" who is to be in charge of the plan. The narrative of the dispute between "Urbanisme" as a cause to be fought, and "urbanisme" as a technique and set of rules takes place between those two clusters

    The preparation of double-walled carbon nanotube/Cu composites by spark plasma sintering, and their hardness and friction properties

    Get PDF
    Double-walled carbon nanotube (DWCNT)/copper composite powders were prepared by a rapid route involving freeze-drying without oxidative acidic treatment or ball-milling. The DWCNTs are not damaged and are homogeneously dispersed in the matrix. Dense specimens were prepared by spark plasma sintering. The Vickers microhardness is doubled, the wear against a steel or an alumina ball seems very low and the average friction coefficient is decreased by a factor of about 4 compared to pure copper. The best results are obtained for a carbon loading (5 vol%) significantly lower than those reported when using multi-walled carbon nanotubes (10–20 vol%). Maximum Hertzian contact pressure data could indicate that the surface DWCNTs and bundles of them are deformed and broken, possibly resulting in the formation of a graphitized lubricating tribofilm in the contac

    The preparation of carbon nanotube (CNT)/copper composites and the effect of the number of CNT walls on their hardness, friction and wear properties

    Get PDF
    Carbon nanotubes with 2, 3, 8 and 20 walls are mixed with a copper powder (micrometer sized) and consolidated by spark plasma sintering. The microhardness of resulting composites is found to be over 50% higher than that for Cu and the friction coefficient against a steel ball is decreased by a factor of 3-4 while the wear and wear rate are reduced by a factor of 10-20. Raman maps of selected specimens outside and inside the worn surface show that double-wall carbon nanotubes remain intact. The reasons for the effect of the number of walls and carbon content are discussed

    Introduction à l'hygiène du travail : un support de formation

    Get PDF
    [Table des matières] A. Cadre et contexte général : Place et démarche de santé au travail ; Place de l'hygiène du travail dans la santé au travail ; Approche pluridisciplinaire et équipe de santé au travail ; Interface avec d'autres acteurs ; Gestion du risque ; Concept général ; Les outils du management ; La notion de risque acceptable. - B. Hygiène et sécurité du travail : Définition et historique de l'hygiène du travail ; Défis et perspectives ; Ethique professionnelle ; Démarche de l'hygiène du travail ; Méthode d'analyse des risques. - C. Identification des dangers : Méthodes ; Etiquetage des produits chimiques. - D. Evaluation des risques : Généralités ; Stratégie ; Normes ; Risques chimiques ; Toxicologie ; Gaz, vapeurs ; Aérosols ; Amiante ; Surveillance biologique ; Laboratoires ; Risques physiques ; Le Bruit ; Les vibrations ; Les radiations ionisantes ; Rayonnement optique et lasers ; Radiofréquence et rayonnements de basse fréquence ; Le stress thermique ; Environnements hypo- et hyperbares ; les risques biologiques ; Facteurs généraux liés à l'ambiance ; Aspects ergonomiques ; Généralités ; Charge physique ; Organisation du travail ; Instruments de mesure. - E. Maîtrise du risque : Organisation de la prévention ; Un nouveau concept de gestion du risque ; Prévention technique ; A la source - substitution ; A l'interface - ventilation ; Sur la cible. Equipements de protection individuelle ; Au niveau du travailleur - Prévention médicale ; Information et formation des travailleurs

    IFNG +874T/A polymorphism is not associated with American tegumentary leishmaniasis susceptibility but can influence Leishmania induced IFN-γ production

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Interferon-gamma is a key cytokine in the protective responses against intracellular pathogens. A single nucleotide polymorphism (SNP) located in the first intron of the human IFN-γ gene can putatively influence the secretion of cytokine with an impact on infection outcome as demonstrated for tuberculosis and other complex diseases. Our aim was to investigate the putative association of IFNG+874T/A SNP with American tegumentary leishmaniasis (ATL) and also the influence of this SNP in the secretion of IFN-γ <it>in vitro</it>.</p> <p>Methods</p> <p>Brazilian ATL patients (78 cutaneous, CL, and 58 mucosal leishmaniasis, ML) and 609 healthy volunteers were evaluated. The genotype of +874 region in the IFN-γ gene was carried out by Amplification Refractory Mutational System (ARMS-PCR). <it>Leishmania</it>-induced IFN-γ production on peripheral blood mononuclear cell (PBMC) culture supernatants was assessed by ELISA.</p> <p>Results</p> <p>There are no differences between +874T/A SNP frequency in cases and controls or in ML versus CL patients. Cutaneous leishmaniasis cases exhibiting AA genotype produced lower levels of IFN-γ than TA/TT genotypes. In mucosal cases, high and low IFN-γ producers were clearly demonstrated but no differences in the cytokine production was observed among the IFNG +874T or A carriers.</p> <p>Conclusion</p> <p>Our results suggest that +874T/A polymorphism was not associated with either susceptibility or severity to leishmaniasis. Despite this, IFNG +874T/A SNP could be involved in the pathogenesis of leishmaniasis by influencing the amount of cytokine released by CL patients, although it could not prevent disease development. On the other hand, it is possible that in ML cases, other potential polymorphic regulatory genes such as TNF-α and IL-10 are also involved thus interfering with IFN-γ secretion.</p

    Radiofrequency and mechanical tests of silver coated CuCrZr contacts for the ITER ion cyclotron antenna

    Get PDF
    The ITER Ion Cyclotron Resonance Heating (ICRH) system is designed to couple to the plasma 20 MW of RF power from two antennas in the 40–55 MHz frequency range during long pulses of up to 3600 s and under various plasma conditions with Edge Localized Modes. Radio-Frequency (RF) contacts are integrated within the ITER ICRH launcher in order to ensure the RF current continuity and ease the mechanical assembly by allowing the free thermal expansion of the Removable Vacuum Transmission Line coaxial conductors during RF operations or during 250 °C baking phases. A material study has been carried out to determine which materials and associated coatings are relevant for RF contacts application in ITER. In parallel, RF tests have been performed with a new prototype of Multi-Contact® LA-CUT/0,25/0 contacts made of silver-coated CuCrZr louvers. During these tests on a RF vacuum resonator, currents between 1.2 kA and 1.3 kA peak have been reached a few tens of times in steady-state conditions without any visible damage on the louvers. A final 62 MHz pulse ending in a 300 s flat top at 1.9 kA resulted in severe damage to the contact. In addition, a test bed which performs sliding test cycles has been built in order to reproduce the wear of the contact prototype after 30 000 sliding cycles on a 3 mm stroke at 175 °C under vacuum. The silver coating of the louvers is removed after approximately a hundred cycles whilst, to the contrary, damage to the CuCrZr louvers is relatively low

    No caminho para o urbanismo. Saturnino de Brito e Édouard Imbeaux, trajetórias profissionais entre Brasil e França

    Get PDF
    The aim of this work is to establish a dialogue between the professional trajectories of two engineers: Saturnino de Brito (1864-1929) and Édouard Imbeaux (1861-1943). They both focussed on the city as object of action and reflection based on an innovative knowledge of hygiene and sanitation issues. The specificity of these trajectories is the association of practice, theoretical reflection and dissemination: these two professionals respectively contributed, in their countries, to the construction of Town planning as a discipline, in particular in relation to its technical approach. The international scene is an important dimension of their activity as it made possible the circulation / comparison of technical knowledge between Europe and Brazil and it contributed to find a specific and appropriate response to the problems of the city. The interaction of local, national and international scene allows another perspective of the professional trajectories of Saturnino de Brito and Edouard Imbeaux.O objetivo deste trabalho é estabelecer um diálogo entre duas trajetórias profissionais, a de Saturnino de Brito (1864-1929) e a de Édouard Imbeaux (1861-1943), que privilegiaram a cidade como objeto de ação e de reflexão, as quais são construídas a partir de um conhecimento inovador sobre as questões de higiene e saneamento. A especificidade desses percursos é a associação da prática com a reflexão teórica e sua difusão: estes dois profissionais contribuíram, assim, cada um em seu país, para a construção da disciplina urbanística, especialmente em sua abordagem técnica. O cenário internacional constitui uma dimensão importante de sua ação, que tornou possível a circulação/confronto de saberes técnicos entre Europa e Brasil e contribuiu com a pesquisa de uma resposta concreta e adaptada aos problemas da cidade. A interação do cenário local, nacional e internacional permite trazer um outro olhar sobre as trajetórias profissionais de Saturnino de Brito e Édouard Imbeaux

    La montagne explorée, étudiée et représentée : évolution des pratiques culturelles depuis le xviiie siècle

    Get PDF
    Le Siècle des lumières, qui consacre l’ouverture des élites européennes à la modernité scientifique, est aussi celui qui pousse les mêmes sociétés vers les sommets et les glaciers des montagnes. Objet de fascination et non plus de crainte, la montagne apparaît, à la suite de Rousseau et Senancour, dans toute sa majesté, à la fois vierge, mystérieuse, repliée sur elle-même et porteuse d’un message d’universalité. Après avoir longtemps suscité peur et préjugés depuis l’Antiquité, la montagne est devenue au xviiie siècle un territoire de conquête et de découverte générant toute une mythologie et un imaginaire qui vont modifier le rapport des sociétés européennes avec le milieu des sommets. Le Congrès national des sociétés historiques et scientifiques rassemble chaque année universitaires, membres de sociétés savantes et jeunes chercheurs. Ce recueil est issu de travaux présentés lors du 142e Congrès sur le thème « Circulations montagnardes, circulations européennes »

    Identification of a BRCA2-Specific modifier locus at 6p24 related to breast cancer risk

    Get PDF
    Common genetic variants contribute to the observed variation in breast cancer risk for BRCA2 mutation carriers; those known to date have all been found through population-based genome-wide association studies (GWAS). To comprehensively identify breast cancer risk modifying loci for BRCA2 mutation carriers, we conducted a deep replication of an ongoing GWAS discovery study. Using the ranked P-values of the breast cancer associations with the imputed genotype of 1.4 M SNPs, 19,029 SNPs were selected and designed for inclusion on a custom Illumina array that included a total of 211,155 SNPs as part of a multi-consortial project. DNA samples from 3,881 breast cancer affected and 4,330 unaffected BRCA2 mutation carriers from 47 studies belonging to the Consortium of Investigators of Modifiers of BRCA1/2 were genotyped and available for analysis. We replicated previously reported breast cancer susceptibility alleles in these BRCA2 mutation carriers and for several regions (including FGFR2, MAP3K1, CDKN2A/B, and PTHLH) identified SNPs that have stronger evidence of association than those previously published. We also identified a novel susceptibility allele at 6p24 that was inversely associated with risk in BRCA2 mutation carriers (rs9348512; per allele HR = 0.85, 95% CI 0.80-0.90, P = 3.9×10−8). This SNP was not associated with breast cancer risk either in the general population or in BRCA1 mutation carriers. The locus lies within a region containing TFAP2A, which encodes a transcriptional activation protein that interacts with several tumor suppressor genes. This report identifies the first breast cancer risk locus specific to a BRCA2 mutation background. This comprehensive update of novel and previously reported breast cancer susceptibility loci contributes to the establishment of a panel of SNPs that modify breast cancer risk in BRCA2 mutation carriers. This panel may have clinical utility for women with BRCA2 mutations weighing options for medical prevention of breast cancer

    Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus

    Get PDF
    A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk
    corecore