Isolement et description de la larve de Leptoconops (Styloconops) albiventris de Meijere, 1915 (Diptera, Ceratopogonidae)

La forme au quatrième stade larvaire de #Leptoconops (#Styloconops) #albiventris$ de Meijere, 1915 est décrite, ainsi que la méthode d'isolement à partir des gîtes larvaire

La thèse sur/par productions scientifiques : une modalité pour écrire la recherche-intervention

International audienceLa réflexion scientifique s’attarde souvent à parler de la connaissance, fruit de la recherche, pour nese questionner que rarement sur les conditions de sa réalisation (Morin, 1999). Cette tâche, qui n’est pasréservée en exclusivité aux épistémologues, comporte plusieurs éléments, dont la dimension scripturalenous semble première : faire une recherche aujourd’hui implique d’emblée sa diffusion par la voie royalede l’écrit, du texte.Cependant, l’écrit scientifique est lié au processus de recherche dont il rend compte. Dans cecontexte, cette contribution se donne pour objectif d’aborder la relation entre le processus d’une modalitéparticulière de recherche, à savoir la recherche-intervention, et son produit textuel : l’écrit dans son unité(un texte de recherche-intervention), mais aussi dans sa pluralité (des écrits de recherche etd’intervention). Nous étudions le cas de la thèse, afin de repenser nos propres travaux soutenus en 2013à partir de l’angle de leurs textualités, mais dans une claire intention de dépasser leurs singularités etd’interroger l’exigence scripturale de la recherche-intervention.L’enjeu est de montrer à la fois en quoi le processus de recherche-intervention implique l’exigence decommuniquer avec les différents acteurs participants de la recherche et comment prendre en chargecette requête.Pour ce faire, nous structurons ce travail en trois parties. La première partie balise la problématique,en abordant la double lecture de la thèse comme processus et comme écrit, et le caractère des conseilspour l’écriture en lien aux particularités de la recherche-intervention. Notre postulat est présenté etassumé : il faut penser le processus de recherche-intervention pour penser l’écrit de ce processus.La deuxième partie montre la pertinence des manuels d’accompagnement à l’écriture de la thèse ence qui concerne une recherche fondamentale, et en explicite les limites pour une recherche-interventionqui nécessite une articulation majeure entre la sphère académique (la recherche) et la sphère sociale(l’intervention). Cette articulation passe aussi par la conception d’écrits pluriels, dont les destinatairesprivilégiés appartiennent à ces deux sphères. Nous proposons la figure d’un chercheur-intervenantplurilingueiii, capable de concevoir un écrit de thèse sur/par productions scientifiques, une unitétranstextuelle composée d’une pluralité de textes adressés à différents destinataires : chercheurs,décideurs et praticiens.La troisième et dernière partie illustre, à partir de nos travaux de thèse (Aussel, 2013; NunezMoscoso, 2013), deux structurations possibles de l’écrit sur/par productions scientifiques. Nousprésentons les cadres généraux de chaque recherche, pour ensuite préciser certains aspects formels del’écrit. Finalement, nous réalisons une analyse critique des potentialités et des limites de ce type d’écritpour rendre compte d’une recherche-intervention

Optical Morphology Evolution of Infrared Luminous Galaxies in GOODS-N

We combine optical morphologies and photometry from HST, redshifts from Keck, and mid-infrared luminosities from Spitzer for an optically selected sample of~800 galaxies in GOODS-N to track morphology evolution of infrared luminous galaxies (LIRGs) since redshift z=1. We find a 50% decline in the number of LIRGs from z~1 to lower redshift, in agreement with previous studies. In addition, there is evidence for a morphological evolution of the populations of LIRGs. Above z=0.5, roughly half of all LIRGs are spiral, the peculiar/irregular to spiral ratio is ~0.7, and both classes span a similar range of L_{IR} and M_B. At low-z, spirals account for one-third of LIRGs, the peculiar to spiral fraction rises to 1.3, and for a given M_B spirals tend to have lower IR luminosity than peculiars. Only a few percent of LIRGs at any redshift are red early-type galaxies. For blue galaxies (U-B < 0.2), M_B is well correlated with log(L_{IR}) with an RMS scatter (about a bivariate linear fit) of ~0.25 dex in IR luminosity. Among blue galaxies that are brighter than M_B = -21, 75% are LIRGs, regardless of redshift. These results can be explained by a scenario in which at high-z, most large spirals experience an elevated star formation rate as LIRGs. Gas consumption results in a decline of LIRGs, especially in spirals, to lower redshifts.Comment: 6 pages, 2 figures, accepted ApJ

The stellar mass function of galaxies in Planck-selected clusters at 0.5 < z < 0.7: new constraints on the timescale and location of satellite quenching

We study the abundance of star-forming and quiescent galaxies in a sample of 21 massive clusters at 0.5<z<0.7, detected with the Planck satellite. We measure the cluster galaxy stellar mass function (SMF), which is a fundamental observable to study and constrain the formation and evolution of galaxies. Our measurements are based on homogeneous and deep multi-band photometry spanning u- to the Ks-band for each cluster and are supported by spectroscopic data from different programs. The galaxy population is separated between quiescent and star-forming galaxies based on their rest-frame U-V and V-J colours. The SMF is compared to that of field galaxies at the same redshifts, using data from the COSMOS/UltraVISTA survey. We find that the shape of the SMF of star-forming galaxies does not depend on environment, while the SMF of quiescent galaxies has a significantly steeper low-mass slope in the clusters compared to the field. We estimate the environmental quenching efficiency (f_EQ), i.e. the probability for a galaxy that would normally be star forming in the field, to be quenched due to its environment. The f_EQ shows no stellar-mass dependence in any environment, but it increases from 40% in the cluster outskirts to ~90% in the cluster centres. The radial signature of f_EQ provides constraints on where the dominant quenching mechanism operates in these clusters and on what timescale. Exploring these using a simple model based on galaxy orbits obtained from an N-body simulation, we find a clear degeneracy between both parameters. For example, the quenching process may either be triggered on a long (~3 Gyr) time scale at large radii (r~8R_500), or happen well within 1 Gyr at r<R_500. The radius where quenching is triggered is at least r_quench> 0.67R_500 (95%CL). The ICM density at this location suggests that ram-pressure stripping of the cold gas is a likely cause of quenching. [Abridged]Comment: 16 pages, 12 figures, accepted for publication in A&

NGC6240: extended CO structures and their association with shocked gas

We present deep CO observations of NGC6240 performed with the IRAM Plateau de Bure Interferometer (PdBI). NGC6240 is the prototypical example of a major galaxy merger in progress, caught at an early stage, with an extended, strongly-disturbed butterfly-like morphology and the presence of a heavily obscured active nucleus in the core of each progenitor galaxy. The CO line shows a skewed profile with very broad and asymmetric wings detected out to velocities of -600 km/s and +800 km/s with respect to the systemic velocity. The PdBI maps reveal the existence of two prominent structures of blueshifted CO emission. One extends eastward, i.e. approximately perpendicular to the line connecting the galactic nuclei, over scales of ~7 kpc and shows velocities up to -400 km/s. The other extends southwestward out to ~7 kpc from the nuclear region, and has a velocity of -100 km/s with respect to the systemic one. Interestingly, redshifted emission with velocities 400 to 800 km/s is detected around the two nuclei, extending in the east-west direction, and partly overlapping with the eastern blue-shifted structure, although tracing a more compact region of size ~1.7 kpc. The overlap between the southwestern CO blob and the dust lanes seen in HST images, which are interpreted as tidal tails, indicates that the molecular gas is deeply affected by galaxy interactions. The eastern blueshifted CO emission is co-spatial with an Halpha filament that is associated with strong H2 and soft X-ray emission. The analysis of Chandra X-ray data provides strong evidence for shocked gas at the position of the Halpha emission. Its association with outflowing molecular gas supports a scenario where the molecular gas is compressed into a shock wave that propagates eastward from the nuclei. If this is an outflow, the AGN are likely the driving force.Comment: Accepted for publication in A&

The ubiK protein is an accessory factor necessary for bacterial Ubiquinone (UQ) biosynthesis and forms a complex with the UQ biogenesis factor UbiJ

Ubiquinone (UQ), also referred to as coenzyme Q, is a widespread lipophilic molecule in both prokaryotes and eukaryotes in which it primarily acts as an electron carrier. Eleven proteins are known to participate in UQ biosynthesis in Escherichia coli, and we recently demonstrated that UQ biosynthesis requires additional, nonenzymatic factors, some of which are still unknown. Here, we report on the identification of a bacterial gene, yqiC, which is required for efficient UQ biosynthesis, and which we have renamed ubiK. Using several methods, we demonstrated that the UbiK protein forms a complex with the C-terminal part of UbiJ, another UQ biogenesis factor we previously identified. We found that both proteins are likely to contribute to global UQ biosynthesis rather than to a specific biosynthetic step, because both ubiK and ubiJ mutants accumulated octaprenylphenol, an early intermediate of the UQ biosynthetic pathway. Interestingly, we found that both proteins are dispensable for UQ biosynthesis under anaerobiosis, even though they were expressed in the absence of oxygen. We also provide evidence that the UbiK-UbiJ complex interacts with palmitoleic acid, a major lipid in E. coli. Last, in Salmonella enterica, ubiK was required for proliferation in macrophages and virulence in mice. We conclude that although the role of the UbiK-UbiJ complex remains unknown, our results support the hypothesis that UbiK is an accessory factor of Ubi enzymes and facilitates UQ biosynthesis by acting as an assembly factor, a targeting factor, or both.Agence Nationale de la Recherche ANR-15-CE11-0001-02Centre National de la Recherche Scientifique PICS07279French State Program "Investissements d'Avenir" ANR-11-LABX-001

Characterizations of Super-regularity and its Variants

Convergence of projection-based methods for nonconvex set feasibility problems has been established for sets with ever weaker regularity assumptions. What has not kept pace with these developments is analogous results for convergence of optimization problems with correspondingly weak assumptions on the value functions. Indeed, one of the earliest classes of nonconvex sets for which convergence results were obtainable, the class of so-called super-regular sets introduced by Lewis, Luke and Malick (2009), has no functional counterpart. In this work, we amend this gap in the theory by establishing the equivalence between a property slightly stronger than super-regularity, which we call Clarke super-regularity, and subsmootheness of sets as introduced by Aussel, Daniilidis and Thibault (2004). The bridge to functions shows that approximately convex functions studied by Ngai, Luc and Th\'era (2000) are those which have Clarke super-regular epigraphs. Further classes of regularity of functions based on the corresponding regularity of their epigraph are also discussed.Comment: 15 pages, 2 figure

Mid-infrared and optical spectroscopy of ultraluminous infrared galaxies: A comparison

New tools from Infrared Space Observatory (ISO) mid-infrared spectroscopy have recently become available to determine the power sources of dust-obscured ultraluminous infrared galaxies (ULIRGs). We compare ISO classifications - starburst or active galactic nucleus (AGN) - with classifications from optical spectroscopy, and with optical/near-infrared searches for hidden broad-line regions. The agreement between mid-infrared and optical classification is excellent if optical LINER spectra are assigned to the starburst group. The starburst nature of ULIRG LINERs strongly supports the suggestion that LINER spectra in infrared-selected galaxies, rather than being an expression of the AGN phenomenon, are due to shocks that are probably related to galactic superwinds. Differences between ISO and optical classification provide clues on the evolution of ULIRGs and on the configuration of obscuring dust. We find few ISO AGN with optical HII or LINER identification, suggesting that highly obscured AGN exist but are not typical for the ULIRG phenomenon in general. Rather, our results indicate that strong AGN activity, once triggered, quickly breaks the obscuring screen at least in certain directions, thus becoming detectable over a wide wavelength range.Comment: aastex, 1 eps figure. Accepted by ApJ (Letters