2,203 research outputs found

    Definition of a New Level One Test Case Measurements of Equilibrium Radiation from an Inductively Coupled Plasma in the Near-UV to Near-IR Spectral Region for a Titan-Type N2-CH4 Mixture. Preliminary Results

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    A test case, using a similar methodology and experimental set-up than previous test case TC5-Level 1 is presented in this paper. An inductively coupled plasma torch, working at atmospheric pressure, is used to create N2-CH4 Titan-like plasma (98%N2 - 2%CH4). The operating frequency and power are 64 MHz and 3 kW respectively. This kind of apparatus allows obtaining plasma in chemical and quasi-thermal equilibrium The spectral measurements cover the [300-800] nm range and are performed inside the induction coil. Each interesting spectrum is calibrated and compared to the line-by-line spectral code SPARTAN used for the simulation of the radiative emission of entry-type plasma. Finally, a discussion is proposed about the nucleation phenomenon which is occurred in the ICP torch with the N2-CH4 plasma. Preliminary studies show the synthesis of nanostructured carbon on the quartz tube.Comment: Radiation of High Temperature Gases in Atmospheric Entry, Heraklion : Greece (2008

    Numerical calculation of the transport coefficients in thermal plasmas

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    -We have performed a new efficient method to calculate numerically the transport coefficients at high temperature. The collision theory was treated to study singularities that occur when evaluating the collision cross section. The transport coefficients (viscosity, diffusion coefficient, thermal and electrical conductivity) depend strongly on nature of the interaction between the particles that form the plasma and that is why it is necessary to determine the interaction potential accurately.Comment: The 9th International Student Conference on Advanced Science and Technology., Dec 2014, Clermont-Ferrand, Franc

    About contemporary challenges of informal activities in Western Africa and Brazil (in Portuguese : A respeito de alguns desafios contemporâneos da informalidade económica...)

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    This study data are based on several sources including official documents that are statistical or economical, as well as specialized literature and fieldwork investigations in collaboration with national university research teams. The present reflection reports on few western African countries and on Brazil characterized by the extent of informal phenomenon and its recent growth. Informal activities have been defined in different ways. The present document stresses on the problem and limits inherent to these definitions. Indeed although the informal phenomenon seems to be quite simple it is in fact complex and multidimensional. The main part of the article is devoted to two questions related to informal process knowledge and also to more concrete economical actions. First the structural importance of informal activities is signalled. Their extreme modernity is proved by nowadays increase due to neoliberal policies led by the governments for the last decades and is analyzed in the document. Second the most interesting challenges that authorities, administrations and specialized agencies have to face concerning informal activities are pointed out. The difficulties are about public policies and action programmes that deal with small business improvement situation as well as their integration in national economical formal channels.Economic Development, Informal economy, Public policies, Micro enterprise, SME, Brazil, Western Africa

    Investigating the effect of paralogs on microarray gene-set analysis

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    Includes abstract.Includes bibliographical references.In order to interpret the results obtained from a microarray experiment, researchers often shift focus from analysis of individual differentially expressed genes to analyses of sets of genes. These gene-set analysis (GSA) methods use previously accumulated biological knowledge from databases such as the Gene Ontology (GO) or KEGG to group genes into sets based on their annotations. They aim to rank these gene sets in a way that reflects their relative importance in the experimental situation in question. The objective is that this approach reveals sets of genes with subtle but coordinated behaviour implicating specific biological processes or pathways in the response under study. Several GSA methods have been proposed and debates have ensued on the statistical foundations of the different approaches and the various hypothesis tests used. In particular, criticism has been directed at methods that rely on a strict cut-off to determine significant genes and those that assume genes are expressed independently. We show that paralogs, which typically have high sequence identity and similar molecular functions also exhibit high correlation in their expression patterns. This, together with the fact that the calculation of gene-set significance by all GSA methods is influenced by the number of genes in the gene set, means that sets with high numbers of paralogs are ranked in a biased manner that reflects more the redundant and dependent nature of para logs than any biological phenomenon

    Monatomic Excitation Temperature in Theoretical Study of Discharge with Liquid Non-Metallic (Tap Water) Electrodes in Air at Atmospheric Pressure

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    The discharge with liquid non-metallic electrodes under study is out of thermal equilibrium. From probe and micro-wave absorption measurements the electronic concentration has been evaluated. The spectral intensities of N2 and Oxygen triplet have been measured locally. In this work, we propose to compare the results of calculation with the experimental results for two hypotheses on the monatomic excitation temperature. The first is when we assume the monatomic excitation temperature close to heavy particle translational temperature and the second is when we assume the monatomic excitation temperature close to the electronic translational temperature

    ACQUISITION AND MODELING OF A SPECTRUM IN A NON THERMAL EQUILIBRIUM PLASMA FORMED IN AIR WITH WATER

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    Spectra in the range of 365-385 nm, corresponding to the Schumann-Runge system of O2 (B33u - X33-g) and to the second positive system of N2 (C30u - B30g) are measured by optical emission spectroscopy in a discharge with liquid non-metallic electrodes (DLNME) in air with water at atmospheric pressure. They are simulated theoretically. This discharge generates a non-equilibrium plasma. In this paper, we first describe the experimental set up. Then, we explain the method of spectra simulation. By comparison of measured and simulated spectra, we determine the rotational and vibrational temperature and the ratio between densities of two upper electronic quantum levels of the two considered systems. The possible mechanism of spectra formation is discussed

    Analyses spectroscopiques d'un plasma CO2-N2 (97%-3%), de type atmosphère martienne, par torche ICP

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    Une torche à plasma à couplage inductif, fonctionnant à la pression atmosphérique, est utilisée pour créer un plasma à partir d'un mélange CO2-N2 reproduisant une atmosphère martienne (97%-3%). La fréquence ainsi que la puissance de fonctionnement de la torche ICP sont respectivement 64 Mhz et 3 kW. Ce type d'outil analytique permet d'obtenir un plasma relativement proche de l'équilibre thermodynamique. La caractérisation du plasma consistera dans un premier temps à déterminer la composition chimique; un code de calcul basé sur la minimisation de l'énergie libre de Gibbs est utilisé. Dans un second temps, les profils de températures seront données à travers les applications de l'inversion d'Abel des systèmes moléculaires considérés. Les mesures spectroscopiques couvrent le domaine [250-800] nm et sont réalisés à l'intérieur des spires inductives. Chaque spectre est ainsi comparé au code SESAM (Simulation de l'Emission Spectrale de l'Atmosphère de Mars)

    Long-term changes in bat activity in Quebec suggest climatic responses and summer niche partitioning associated with white-nose syndrome

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    In North America, the greatest and most sudden threat to hibernating bats is whitenose syndrome (WNS), which has caused massive declines in populations since 2006. Other determinants of bat dynamics, such as the climate, and the effect of reduction in the number of individuals sharing foraging space and summer roosting habitat may have an effect on population dynamics. We analyzed transect acoustic bat surveys conducted with ultrasonic detectors in 16 regions in Quebec, Canada, between 2000 and 2015. We used piecewise regression to describe changes in activity over time for each species and a meta-analytic approach to measure its association with the North Atlantic Oscillation (NAO). As expected, mouse-eared bat (Myotis spp.) activity sharply declined after the onset of WNS, down by 79% after 3 years. In contrast, big brown/silver-haired bat activity increased over the same period, possibly due to a release of competition. Hoary bats and red bats remained present, although their activity did not increase. Myotis activity was positively correlated with a one-year lag to the NAO index, associated with cold conditions in winter, but warm autumns. Big brown/silver-haired and hoary bats were also more active during NAO-positive years but without a lag. We conclude that combinations of threats may create rapid shifts in community compositions and that a more balanced research agenda that integrates a wider range of threats would help better understand and manage those changes

    Гранитоиды обрамления Криворожской структуры. Проблемы корреляции геологических тел и комплексов

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    Current population genetic models fail to cope with genetic differentiation for species with large, contiguous and heterogeneous distribution. We show that in such a case, genetic differentiation can be predicted at equilibrium by circuit theory, where conductance corresponds to abundance in species distribution models (SDM). Circuit-SDM approach was used for the phylogeographic study of the lepidopteran cereal stemborer Busseola fusca Füller (Noctuidae) across sub-Saharan Africa. Species abundance was surveyed across its distribution range. SDM models were optimized and selected by cross validation. Relationship between observed matrices of genetic differentiation between individuals, and matrices of resistance distance was assessed through Mantel tests and redundancy discriminant analyses (RDA). A total of 628 individuals from 130 localities in 17 countries were genotyped at 7 microsatellite loci. Six population clusters were found based on a Bayesian analysis. The eastern margin of Dahomey Gap between East and West Africa was the main factor of genetic differentiation. The SDM projections at present, last interglacial and last glacial maximum periods were used for estimation of circuit resistance between locations of genotyped individuals. For all periods of time, when using either all individuals or only East-African individuals, partial Mantel r and RDA analyses conditioning on geographic distance were found significant. Under future projections (year 2080), partial r and RDA significance were different. From this study, it is concluded that analytical solutions provided by circuit theory are useful for the evolutionary management of populations and for phylogeographic analysis when coalescence times are not accessible by approximate Bayesian simulations

    Socio-Cultural Perceptions and Representations of Dementia in Brazzaville, Republic of Congo: The EDAC Survey

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    Background: Dementia will concern more and more people in the developing countries, but the perception people have of dementia in these areas has not yet been studied. Method: During a general population survey (EDAC) carried out in Brazzaville (Republic of Congo), 27 elderly persons suspected of having dementia and 31 of their relatives, 90 cognitively impaired elderly persons and 92 of their relatives, as well as 33 hospital workers were interviewed according to the Explanatory Model Interview Catalogue. Results: Item prominence ratings indicate that the attention was mainly on the emotional and socio-economic consequences (scores >1.0 out of 5 points). Ageing and mental stress are the main perceived causes. Hospital workers are more aware of public stigma. Conclusion: The socio-cultural components of the dementia phenomenon have to be taken into account to enforce public health and social measures
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