487 research outputs found

    Biochemical characterization, molecular cloning and localization of a putative odorant-binding protein in the honey bee Apis mellifera L. (Hymenoptera: Apidea)

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    AbstractA honey bee antennal water-soluble protein, APS2, was purified and characterized as the first Hymenoptera putative odorant-binding protein. Comparison of its measured Mr (13 695.2±1.6) to that of the corresponding cDNA clone shows it does not undergo any post-translational modification other than a 19-residue signal peptide cleavage and formation of three disulfide bridges. These biochemical features are close to those of Lepidoptera odorant-binding proteins. In situ hybridization experiments demonstrated its specific expression in olfactory areas. Based on its higher expression in the worker than in the drone, ASP2 might be more involved in general odorant than in sex pheromone detection

    Correlations among global photometric properties of disk galaxies

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    Using a two-dimensional galaxy image decomposition technique, we extract global bulge and disk parameters for a complete sample of early type disk galaxies in the near infrared K band. We find significant correlation of the bulge parameter n with the central bulge surface brightness ÎŒb(0)\mu_b(0) and with effective radius r_e. Using bivar iate analysis techniques, we find that log⁥n\log n, log⁥re\log r_e and ÎŒb(0)\mu_b(0) are distributed in a plane with small scatter. We do not find a strong correlation of n with bulge-to-disk luminosity ratio, contrary to earlier reports. r_e and the disk scale length r_d are well correlated for these early type disk galaxies, but with large scatter. We examine the implications of our results to various bulge formation scenarios in disk galaxies.Comment: 14 pages, LaTeX including 14 figures. To appear in the Astrophysical Journa

    Ising model with memory: coarsening and persistence properties

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    We consider the coarsening properties of a kinetic Ising model with a memory field. The probability of a spin-flip depends on the persistence time of the spin in a state. The more a spin has been in a given state, the less the spin-flip probability is. We numerically studied the growth and persistence properties of such a system on a two dimensional square lattice. The memory introduces energy barriers which freeze the system at zero temperature. At finite temperature we can observe an apparent arrest of coarsening for low temperature and long memory length. However, since the energy barriers introduced by memory are due to local effects, there exists a timescale on which coarsening takes place as for the Ising model. Moreover the two point correlation functions of the Ising model with and without memory are the same, indicating that they belong to the same universality class.Comment: 10 pages, 7 figures; some figures and some comments adde

    Photometric structure of the peculiar galaxy ESO 235-G58

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    We present the near-infrared and optical properties of the peculiar galaxy ESO 235-G58, which resembles a late-type ringed barred spiral seen close to face-on. However, the apparent bar of ESO 235-G58 is in reality an edge-on disk galaxy of relatively low luminosity. We have analyzed the light and color distributions of ESO 235-G58 in the NIR and optical bands and compared them with the typical properties observed for other morphological galaxy types, including polar ring galaxies. Similar properties are observed for ESO 235-G58, polar ring galaxies, and spiral galaxies, which leads us to conclude that this peculiar system is a polar-ring-related galaxy, characterized by a low inclined ring/disk structure, as pointed out by Buta & Crocker in an earlier study, rather than a barred galaxy.Comment: 16 pages, 15 figures, accepted for publication in Astronomy & Astrophysic

    U-Pb zircon age of 548 Ma for the leptynites (high-grade felsic rocks) of the central part of the Maures Massif. Geodynamic significance of the so-called leptyno-amphibolitic complexes of the Variscan belt of western Europe

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    Le complexe leptyno-amphibolitique de la partie centrale du massif des Maures a fait l’objet d’une Ă©tude gĂ©ochronologique U-Pb sur zircons et Rb-Sr, et isotopique Sm-Nd. La mise en place du protolithe des leptynites a Ă©tĂ© datĂ©e Ă  548 Ma, Ăąge nettement plus ancien que ceux (Ordovicien infĂ©rieur) mesurĂ©s sur d’autres complexes leptyno-amphibolitiques. L’étude Rb-Sr sur roches totales et minĂ©raux sĂ©parĂ©s a permis de dater l’amphibolitisation Ă  348 Ma. Les isotopes du Nd montrent que les amphibolites ont des signatures nettement mantelliques. Les trois faciĂšs acides analysĂ©s portent une empreinte crustale relativement importante. L’un d’entre eux peut ĂȘtre interprĂȘtĂ© comme un mĂ©lange simple entre deux sources, respectivement similaires Ă  celle des amphibolites et Ă  celle des deux autres leptynites. Ces derniĂšres, quant Ă  elles, tĂ©moignent d’un apport d’une autre source mantellique, distincte de celle des amphibolites, probablement du type basalte alcalin continental. Les rĂ©sultats obtenus indiquent que les Maures centrales et le sud du Massif central faisaient peut-ĂȘtre partie de la mĂȘme unitĂ© structurale prĂ©-Varisque. L’absence d’indice de lien gĂ©nĂ©tique clair entre les protolithes des deux termes du complexe leptyno-amphibolitique repose le problĂšme de la signification gĂ©odynamique de ces formations

    Particle Image Velocimetry (PIV) measurements in a water film, application to a tire rolling through a puddle

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    International audienceA measurement method based on Particle Image Velocimetry with refraction of the laser sheet at a win-dow/water interface is proposed for the measurement of the velocity field of a water flow formed by a tire moving inside a water puddle. This study focuses of the feasibility and repeatability of this optical measurement method. The characterization of the optical properties of the measurement technique defines the integration effect in height of the measurement method. The analysis of the overall features of the flow is focused on two main zones in front and around the tire. The flow inside the first zone is defined by a characteristic velocity of the water displaced in an area located in front of the tire ; in the second zone a characteristic velocity representative of the flow in the vicinity of the shoulder of the tire is also defined. Correlations of both characteristic velocities with the car speed and water film height are established. New and worn tires were tested in this work

    Goal-directed fluid management based on pulse pressure variation monitoring during high-risk surgery: a pilot randomized controlled trial

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    Abstract\ud \ud \ud \ud Introduction\ud \ud Several studies have shown that maximizing stroke volume (or increasing it until a plateau is reached) by volume loading during high-risk surgery may improve post-operative outcome. This goal could be achieved simply by minimizing the variation in arterial pulse pressure (ΔPP) induced by mechanical ventilation. We tested this hypothesis in a prospective, randomized, single-centre study. The primary endpoint was the length of postoperative stay in hospital.\ud \ud \ud \ud Methods\ud \ud Thirty-three patients undergoing high-risk surgery were randomized either to a control group (group C, n = 16) or to an intervention group (group I, n = 17). In group I, ΔPP was continuously monitored during surgery by a multiparameter bedside monitor and minimized to 10% or less by volume loading.\ud \ud \ud \ud Results\ud \ud Both groups were comparable in terms of demographic data, American Society of Anesthesiology score, type, and duration of surgery. During surgery, group I received more fluid than group C (4,618 ± 1,557 versus 1,694 ± 705 ml (mean ± SD), P < 0.0001), and ΔPP decreased from 22 ± 75 to 9 ± 1% (P < 0.05) in group I. The median duration of postoperative stay in hospital (7 versus 17 days, P < 0.01) was lower in group I than in group C. The number of postoperative complications per patient (1.4 ± 2.1 versus 3.9 ± 2.8, P < 0.05), as well as the median duration of mechanical ventilation (1 versus 5 days, P < 0.05) and stay in the intensive care unit (3 versus 9 days, P < 0.01) was also lower in group I.\ud \ud \ud \ud Conclusion\ud \ud Monitoring and minimizing ΔPP by volume loading during high-risk surgery improves postoperative outcome and decreases the length of stay in hospital.\ud \ud \ud \ud Trial registration\ud \ud NCT00479011The authors thank Maria De Amorim (Paris, France) and Julia Fukushima (SĂŁo Paulo, SP, Brazil) for help in data analysis, Dr Julia Wendon (London, UK) for reviewing the manuscript, and Dixtal (Sao Paulo, SP, Brazil) for providing the software for the automatic calculation of ?PP.The authors thank Maria De Amorim (Paris, France) and Julia Fukushima (SĂŁo Paulo, SP, Brazil) for help in data analysis, Dr Julia Wendon (London, UK) for reviewing the manuscript, and Dixtal (Sao Paulo, SP, Brazil) for providing the software for the automatic calculation of ?PP
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