13 research outputs found

    FUSE Measurements of Far-Ultraviolet Extinction. III. The Dependence on R(V) and Discrete Feature Limits from 75 Galactic Sightlines

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    We present a sample of 75 extinction curves derived from FUSE far-ultraviolet spectra supplemented by existing IUE spectra. The extinction curves were created using the standard pair method based on a new set of dereddened FUSE+IUE comparison stars. Molecular hydrogen absorption features were removed using individualized H_2 models for each sightline. The general shape of the FUSE extinction (8.4 micron^-1 < lambda^-1 < 11 micron^-1) was found to be broadly consistent with extrapolations from the IUE extinction (3.3 micron-1 < lambda^-1 < 8.6 micron^-1) curve. Significant differences were seen in the strength of the far-UV rise and the width of the 2175 A bump. All the FUSE+IUE extinction curves had positive far-UV slopes giving no indication that the far-UV rise was turning over at the shortest wavelengths. The dependence of A(lambda)/A(V) versus R(V)^-1 in the far-UV using the sightlines in our sample was found to be stronger than tentatively indicated by previous work. We present an updated R(V) dependent relationship for the full UV wavelength range (3.3 micron^-1 <= lambda^-1 <= 11 micron^-1). Finally, we searched for discrete absorption features in the far-ultraviolet. We found a 3 sigma upper limit of ~0.12 A(V) on features with a resolution of 250 (~4 A width) and 3 sigma upper limits of ~0.15 A(V) for lambda^-1 < 9.6 micron^-1 and ~0.68 A(V) for lambda^-1 > 9.6 micron^-1 on features with a resolution of 10^4 (~0.1 A width).Comment: 16 pages, 13 figures, ApJ, in pres

    Duchamp's Erotic Stereoscopic Exercises

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    This article explores certain links between medicine and art, with regard to their use of stereoscopy. I highlight a work by the artist Marcel Duchamp (the ready-made Stéréoscopie a la Main) and stereoscopic cards used in ophthalmic medicine. Both instances involve the drawing of graphic marks over previously existing stereoscopic cards. This similarity between Stéréoscopie a la Main and stereoscopic cards is echoed in the form of "stereoscopic exercises." Stereoscopic exercises were prescribed by doctors to be performed with the stereoscope as early as 1864. Stereoscopic cards were widely diffused in the 19th century, often promoted as "stay-at-home travel." It was over such kinds of materials that both Marcel Duchamp and doctors of ophthalmic medicine drew their graphic marks. I explore Duchamp's Stéréoscopie a la Main as a hypothetical basis for stereoscopic exercises of different types, proposing that this rectified ready-made is the locus for erotic stereoscopic exercises.Este artigo busca explorar certos elos entre a medicina e a arte por meio da estereoscopia. Destaca-se uma obra do artista Marcel Duchamp (o ready-made Stéréoscopie a la Main) e cartÔes estereoscópicos usados na oftalmologia. As duas instùncias envolvem o desenho de marcas gråficas sobre cartÔes estereoscópicos pré-existentes. A similaridade entre Stéréoscopie a la Main e os ditos cartÔes ecoa também na forma dos exercícios estereoscópicos. O cartão estereoscópico foi amplamente difundido na segunda metade do séc. XIX, frequentemente na forma da "viagem sem sair de casa." Foi sobre esse tipo de material que tanto médicos quanto Marcel Duchamp desenharam suas marcas. Explora-se a obra Stéréoscopie a la Main como um sítio hipotético para uma espécie de exercício, propondo que tal ready-made retificado seja um lugar para exercícios estereoscópicos eróticos

    Rethinking capital mobility, re‐regulating financial markets

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    The globalisation hypothesis has altered many of the common-sense ‘truths’ around which the social world is organised.* In particular, globalisation is thought to restrict the parameters of the politically and economically possible. Indeed, the notion of constrained choice is so pronounced that we are increasingly confronted with the image of globalisation’s ‘logic of no alternative’; an image which is predicated on the assumption of perfect capital mobility. Capital is considered to be sufficiently rational to take advantage of enhanced exit options from the national economy in circumstances in which its interests are served by moving off-shore. Moreover, global markets are also assumed to have exploited contemporary technological developments to such an extent that they now clear instantaneously; consequently, allowing capital to further its interests wherever in the world new profit opportunities arise. Thus, we are presented with the fundamental ‘reality’ of globalisation as currently narrated throughout much of the west: unless the market can be allowed to restore a competitive global equilibrium, capital will exit high-wage, high-cost western economies and re-locate in lower-wage, lower-cost, newly industrialising economies. Under the auspices of ever more hostile wage competition from the newly industrialising economies, globalisation is commonly presumed to act as a trigger for an ‘inevitable’ job displacement effect as capital deserts the advanced industrialised economies

    Star cluster catalogues for the LEGUS dwarf galaxies

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    We present a new Bayesian hierarchical model (BHM) named Steve for performing Type Ia supernova (SN Ia) cosmology fits. This advances previous works by including an improved treatment of Malmquist bias, accounting for additional sources of systematic uncertainty, and increasing numerical efficiency. Given light-curve fit parameters, redshifts, and host-galaxy masses, we fit Steve simultaneously for parameters describing cosmology, SN Ia populations, and systematic uncertainties. Selection effects are characterized using Monte Carlo simulations. We demonstrate its implementation by fitting realizations of SN Ia data sets where the SN Ia model closely follows that used in Steve. Next, we validate on more realistic SNANA simulations of SN Ia samples from the Dark Energy Survey and low-redshift surveys (DES Collaboration et al. 2018). These simulated data sets contain more than 60,000 SNe Ia, which we use to evaluate biases in the recovery of cosmological parameters, specifically the equation of state of dark energy, w. This is the most rigorous test of a BHM method applied to SN Ia cosmology fitting and reveals small w biases that depend on the simulated SN Ia properties, in particular the intrinsic SN Ia scatter model. This w bias is less than 0.03 on average, less than half the statistical uncertainty on w. These simulation test results are a concern for BHM cosmology fitting applications on large upcoming surveys; therefore, future development will focus on minimizing the sensitivity of Steve to the SN Ia intrinsic scatter model.AA acknowledges the support of the Swedish Research Council (Vetenskapsradet) and the Swedish National Space Board (SNSB). DAG acknowledges support by the German Aerospace Center (DLR) and the Federal Ministry for Economic Affairs and Energy (BMWi) through program 50OR1801 ‘MYSST: Mapping Young Stars in Space and Time’

    Quantification des vitesses de dĂ©pĂŽt par temps sec et documentation des processus d’émission des aĂ©rosols sur couvert naturel : du nanomĂštre au micron

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    The particles emitted into the atmosphere during chronic or accidental release by the nuclear plants can be subjected, after dispersion, to vertical flows by dry weather: dry deposition and resuspension. Vertical flows in dry weather are characterized by the vertical transfer rate, which is the ratio between the particle flux and the atmospheric concentration of the aerosol in the vicinity of the surface. When this speed is positive, it is a dry deposition rate (Vd in m.s-1) and conversely, when it is negative, it is a transmission rate. It is important to study their dry deposition in a prairial environment. Indeed, the products resulting from this environment are a component of the human food chain via livestock. For particles less than 1 ÎŒm, there is a lack of experimental data, which results in uncertainty about the results of the models, which can reach up to two orders of magnitude. In addition, there are no in situ deposition rate measurement data available for particles less than 10 nm. These particles are derived from the gas / particle conversion (nucleation) and may relate to certain radionuclides such as iodine (129, 131I).After their deposition, these radionuclides can be resuspended under the effect of the stress submitted by the wind on the canopy. Such a phenomenon is suspected around the Fukushima nuclear power plant. The aerosol resuspension processes are characterized by the vertical transfer rate (m.s-1) but also by the re-suspension coefficient (Ks in m-1) which is the ratio of atmospheric concentration to surface concentration of particles. Relative uncertainties of 2 to 3 orders of magnitude on the resuspension coefficients exist. The resuspension concerns all the particles present on the canopy, whether they are inert or living (fungi, bacteria, yeasts, etc.). Unlike inert particles, these living particles can assimilate and concentrate radionuclides. However, there is very little data on the resuspension of microorganisms and bacteria in particular. In this context, the objectives of the thesis are to quantify the dry deposition rate as a function of the particle size and the main micrometeorological parameters in the range 1.5 nm - 1.2 ÎŒm. The second objective is to document the processes of emission of the bacteriaLes particules Ă©mises, dans l’atmosphĂšre, lors de rejets chroniques ou accidentels par les installations peuvent ĂȘtre soumises aprĂšs dispersion Ă  des flux verticaux par temps sec : le dĂ©pĂŽt sec et la remise en suspension. Les flux verticaux par temps sec sont caractĂ©risĂ©s par la vitesse de transfert vertical, qui est le rapport entre le flux de particules et la concentration atmosphĂ©rique de l'aĂ©rosol au voisinage de la surface. Lorsque cette vitesse est positive, c‘est une vitesse de dĂ©pĂŽt sec (Vd en m.s-1) et inversement, lorsqu’elle est nĂ©gative, c’est une vitesse d’émission. Il est important d'Ă©tudier leur dĂ©pĂŽt sec en milieu prairial. En effet, les produits issus de ce milieu sont une composante de la chaine alimentaire de l’homme via l’élevage. Pour les particules de moins de 1 ÎŒm, il y a un manque de donnĂ©es expĂ©rimentales, ce qui entraĂźne une incertitude sur les rĂ©sultats des modĂšles, qui peuvent atteindre jusqu'Ă  deux ordres de grandeur. En outre, il n'existe pas de donnĂ©es de mesure de la vitesse de dĂ©pĂŽt in situ disponibles pour les particules infĂ©rieures Ă  10 nm. Ces particules sont issues de rĂ©action gaz/particules (nuclĂ©ation) et peuvent concerner certains radionuclĂ©ides tels que l’iode (129,131I).AprĂšs leur dĂ©pĂŽt, ces radionuclĂ©ides peuvent ĂȘtre remis en suspension sous l’effet de la contrainte soumise par le vent sur le couvert. Un tel phĂ©nomĂšne est soupçonnĂ© autour de la centrale nuclĂ©aire de Fukushima. Les processus de remise en suspension des aĂ©rosols, est caractĂ©risĂ©e par la vitesse de transfert vertical (m.s-1) mais Ă©galement par le coefficient de remise en suspension (Ks en m-1) qui est le rapport entre la concentration atmosphĂ©rique et la concentration surfacique de particules. Des incertitudes rĂ©manentes de 2 Ă  3 ordres de grandeurs sur les coefficients de remise en suspension existent. La remise en suspension concerne l’ensemble des particules prĂ©sentent sur le couvert qu’elles soient inertes ou vivantes (champignons, bactĂ©ries, levures
). Contrairement aux particules inertes, ces particules vivantes peuvent assimiler et concentrer les radionuclĂ©ides. Cependant, il y a trĂšs peu de donnĂ©es concernant la remise en suspension des microorganismes et des bactĂ©ries en particulier. Dans ce contexte, les objectifs de la thĂšse sont de quantifier la vitesse de dĂ©pĂŽt sec en fonction de la taille des particules et des principaux paramĂštres micromĂ©tĂ©orologique dans la gamme 1,5 nm – 1,2 ”m. Le second objectif est de documenter les processus d’émission des bactĂ©rie

    Quantification of dry deposition velocities and identification of aerosol emissions onto natural surfaces

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    Les particules Ă©mises, dans l’atmosphĂšre, lors de rejets chroniques ou accidentels par les installations peuvent ĂȘtre soumises aprĂšs dispersion Ă  des flux verticaux par temps sec : le dĂ©pĂŽt sec et la remise en suspension. Les flux verticaux par temps sec sont caractĂ©risĂ©s par la vitesse de transfert vertical, qui est le rapport entre le flux de particules et la concentration atmosphĂ©rique de l'aĂ©rosol au voisinage de la surface. Lorsque cette vitesse est positive, c‘est une vitesse de dĂ©pĂŽt sec (Vd en m.s-1) et inversement, lorsqu’elle est nĂ©gative, c’est une vitesse d’émission. Il est important d'Ă©tudier leur dĂ©pĂŽt sec en milieu prairial. En effet, les produits issus de ce milieu sont une composante de la chaine alimentaire de l’homme via l’élevage. Pour les particules de moins de 1 ÎŒm, il y a un manque de donnĂ©es expĂ©rimentales, ce qui entraĂźne une incertitude sur les rĂ©sultats des modĂšles, qui peuvent atteindre jusqu'Ă  deux ordres de grandeur. En outre, il n'existe pas de donnĂ©es de mesure de la vitesse de dĂ©pĂŽt in situ disponibles pour les particules infĂ©rieures Ă  10 nm. Ces particules sont issues de rĂ©action gaz/particules (nuclĂ©ation) et peuvent concerner certains radionuclĂ©ides tels que l’iode (129,131I).AprĂšs leur dĂ©pĂŽt, ces radionuclĂ©ides peuvent ĂȘtre remis en suspension sous l’effet de la contrainte soumise par le vent sur le couvert. Un tel phĂ©nomĂšne est soupçonnĂ© autour de la centrale nuclĂ©aire de Fukushima. Les processus de remise en suspension des aĂ©rosols, est caractĂ©risĂ©e par la vitesse de transfert vertical (m.s-1) mais Ă©galement par le coefficient de remise en suspension (Ks en m-1) qui est le rapport entre la concentration atmosphĂ©rique et la concentration surfacique de particules. Des incertitudes rĂ©manentes de 2 Ă  3 ordres de grandeurs sur les coefficients de remise en suspension existent. La remise en suspension concerne l’ensemble des particules prĂ©sentent sur le couvert qu’elles soient inertes ou vivantes (champignons, bactĂ©ries, levures
). Contrairement aux particules inertes, ces particules vivantes peuvent assimiler et concentrer les radionuclĂ©ides. Cependant, il y a trĂšs peu de donnĂ©es concernant la remise en suspension des microorganismes et des bactĂ©ries en particulier. Dans ce contexte, les objectifs de la thĂšse sont de quantifier la vitesse de dĂ©pĂŽt sec en fonction de la taille des particules et des principaux paramĂštres micromĂ©tĂ©orologique dans la gamme 1,5 nm – 1,2 ”m. Le second objectif est de documenter les processus d’émission des bactĂ©riesThe particles emitted into the atmosphere during chronic or accidental release by the nuclear plants can be subjected, after dispersion, to vertical flows by dry weather: dry deposition and resuspension. Vertical flows in dry weather are characterized by the vertical transfer rate, which is the ratio between the particle flux and the atmospheric concentration of the aerosol in the vicinity of the surface. When this speed is positive, it is a dry deposition rate (Vd in m.s-1) and conversely, when it is negative, it is a transmission rate. It is important to study their dry deposition in a prairial environment. Indeed, the products resulting from this environment are a component of the human food chain via livestock. For particles less than 1 ÎŒm, there is a lack of experimental data, which results in uncertainty about the results of the models, which can reach up to two orders of magnitude. In addition, there are no in situ deposition rate measurement data available for particles less than 10 nm. These particles are derived from the gas / particle conversion (nucleation) and may relate to certain radionuclides such as iodine (129, 131I).After their deposition, these radionuclides can be resuspended under the effect of the stress submitted by the wind on the canopy. Such a phenomenon is suspected around the Fukushima nuclear power plant. The aerosol resuspension processes are characterized by the vertical transfer rate (m.s-1) but also by the re-suspension coefficient (Ks in m-1) which is the ratio of atmospheric concentration to surface concentration of particles. Relative uncertainties of 2 to 3 orders of magnitude on the resuspension coefficients exist. The resuspension concerns all the particles present on the canopy, whether they are inert or living (fungi, bacteria, yeasts, etc.). Unlike inert particles, these living particles can assimilate and concentrate radionuclides. However, there is very little data on the resuspension of microorganisms and bacteria in particular. In this context, the objectives of the thesis are to quantify the dry deposition rate as a function of the particle size and the main micrometeorological parameters in the range 1.5 nm - 1.2 ÎŒm. The second objective is to document the processes of emission of the bacteri

    The influence of wine polymers on the spontaneous precipitation of calcium tartrate in a model wine solution

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    The influence of wine polymers on the spontaneous precipitation of calcium tartrate in a model wine system has been examined. Rhamnogalacturonan-I was identified as the most effective inhibitor (precipitation induction time of 180min compared with 7min for the standard model). It is argued that this is a consequence of rhamnogalacturonan-I's ability to participate in the egg-box' type sequestration of calcium ions. The more structurally complex rhamnogalacturonan-II had only a minor influence on the induction time (22min). Arabinogalactan proteins and mannoproteins also have little influence with induction times ranging from 12 to 15min. An ultra-filtration study of four Chardonnay wines, prepared with and without the use of pectolytic enzymes, was performed in a search for conditions that might maximise the concentration of rhamnogalacturonan-I. However, rhamnogalacturonan-I could not be identified in any of the four wines. Implications of these observations, specifically the need to understand the inhibition exerted by specific uronic acids, for winemaking and calcium tartrate precipitation are discussed

    Mesures des vitesses de dépÎt sec pour les particules atmosphériques de 1,5 nm à 1,2 ”m : la courbe en "V"

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    National audienceTo assess the impact of an accidental or chronic radionuclide release in form of aerosol particles in the atmosphere, it is important to study their dry deposition above a grassland. Indeed, products derived from this environment are a component of the human food chain via livestock. For particles of less than 1 ”m, there is a lack of experimental data in this regard, leading to uncertainty in terms of the results of models, which can reach up to two orders of magnitude. Moreover, there is no in situ deposition velocity measurement data available for particles that are smaller than 10 nm. These particles were formed by gas/particles reaction (nucleation) and may affect different radionuclides like iodine (129,131 I). The objective of this study is to measure and analyse the dry deposition velocity for aerosol particles with a particle size of between 1.5 nm and 1.2 ”m, with particular focus on the particle size less than 10 nm. To this end, three different methods during 4 experimental campaigns were used above a grassland.Pour Ă©valuer l'impact d'un rejet accidentel ou chronique sous forme de particules dans l'atmosphĂšre, il est important d'Ă©tudier leur dĂ©pĂŽt sec en milieu prairial. En effet, les produits issus de ce milieu sont une composante de la chaine alimentaire de l'homme via l'Ă©levage. Pour les particules de moins de 1 ÎŒm, il y a un manque de donnĂ©es expĂ©rimentales, ce qui entraĂźne une incertitude sur les rĂ©sultats des modĂšles, qui peuvent atteindre jusqu'Ă  deux ordres de grandeur. En outre, il n'existe pas de donnĂ©es de mesure de la vitesse de dĂ©pĂŽt in situ disponibles pour les particules infĂ©rieures Ă  10 nm. Ces particules sont issues de rĂ©action gaz/particules (nuclĂ©ation) et peuvent concerner certains radionuclĂ©ides tels que l'iode (129,131 I). L'objectif de cette Ă©tude est de mesurer et de modĂ©liser la vitesse de dĂ©pĂŽt sec pour les particules avec une granulomĂ©trie comprise entre 1,5 nm et 1,2 ÎŒm, particuliĂšrement la taille de particules infĂ©rieures Ă  10 nm. À cette fin, trois diffĂ©rentes mĂ©thodes expĂ©rimentales in situ ont Ă©tĂ© mises au point et utilisĂ©s durant 4 campagnes expĂ©rimentales au-dessus d'une prairie
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