Institution
Aix-Marseille University
Education•Marseille, France•
About: Aix-Marseille University is a education organization based out in Marseille, France. It is known for research contribution in the topics: Population & Galaxy. The organization has 24326 authors who have published 54240 publications receiving 1455416 citations. The organization is also known as: University Aix-Marseille & université d'Aix-Marseille.
Topics: Population, Galaxy, Context (language use), Redshift, Medicine
Papers published on a yearly basis
Papers
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TL;DR: In this article, a sample of giant transiting exoplanets detected by the Kepler telescope with orbital periods up to 400 days was used to reveal the nature of these candidates and measure a false positive rate of 54.6 +/- 6.5% for giant-planet candidates orbiting within 400 days of period.
Abstract: While giant extrasolar planets have been studied for more than two decades now, there are still some open questions as to their dominant formation and migration processes, as well as to their atmospheric evolution in different stellar environments. In this paper, we study a sample of giant transiting exoplanets detected by the Kepler telescope with orbital periods up to 400 days. We first defined a sample of 129 giant-planet candidates that we followed up with the SOPHIE spectrograph (OHP, France) in a 6-year radial velocity campaign. This allowed us to unveil the nature of these candidates and to measure a false-positive rate of 54.6 +/- 6.5% for giant-planet candidates orbiting within 400 days of period. Based on a sample of confirmed or likely planets, we then derived the occurrence rates of giant planets in different ranges of orbital periods. The overall occurrence rate of giant planets within 400 days is 4.6 +/- 0.6%. We recovered, for the first time in the Kepler data, the different populations of giant planets reported by radial velocity surveys. Comparing these rates with other yields, we find that the occurrence rate of giant planets is lower only for hot Jupiters but not for the longer-period planets. We also derive a first measurement of the occurrence rate of brown dwarfs in the brown-dwarf desert with a value of 0.29 +/- 0.17%. Finally, we discuss the physical properties of the giant planets in our sample. We confirm that giant planets receiving moderate irradiation are not inflated, but we find that they are on average smaller than predicted by formation and evolution models. In this regime of low-irradiated giant planets, we find a possible correlation between their bulk density and the iron abundance of the host star, which needs more detections to be confirmed.
264 citations
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TL;DR: In this paper, a split-root assay was performed to mimic a heterogeneous environment, after which a transcriptomic analysis identified groups of genes either locally or systemically regulated by P(i) starvation at the transcriptional level.
Abstract: Phosphate is a crucial and often limiting nutrient for plant growth. To obtain inorganic phosphate (P(i) ), which is very insoluble, and is heterogeneously distributed in the soil, plants have evolved a complex network of morphological and biochemical processes. These processes are controlled by a regulatory system triggered by P(i) concentration, not only present in the medium (external P(i) ), but also inside plant cells (internal P(i) ). A 'split-root' assay was performed to mimic a heterogeneous environment, after which a transcriptomic analysis identified groups of genes either locally or systemically regulated by P(i) starvation at the transcriptional level. These groups revealed coordinated regulations for various functions associated with P(i) starvation (including P(i) uptake, P(i) recovery, lipid metabolism, and metal uptake), and distinct roles for members in gene families. Genetic tools and physiological analyses revealed that genes that are locally regulated appear to be modulated mostly by root development independently of the internal P(i) content. By contrast, internal P(i) was essential to promote the activation of systemic regulation. Reducing the flow of P(i) had no effect on the systemic response, suggesting that a secondary signal, independent of P(i) , could be involved in the response. Furthermore, our results display a direct role for the transcription factor PHR1, as genes systemically controlled by low P(i) have promoters enriched with P1BS motif (PHR1-binding sequences). These data detail various regulatory systems regarding P(i) starvation responses (systemic versus local, and internal versus external P(i) ), and provide tools to analyze and classify the effects of P(i) starvation on plant physiology.
264 citations
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University of Oulu1, University of Turku2, European Southern Observatory3, University of Alabama4, National Radio Astronomy Observatory5, University of Arizona6, Peking University7, University of La Laguna8, Spanish National Research Council9, Aix-Marseille University10, California Institute of Technology11, Seoul National University12, Space Telescope Science Institute13, Complutense University of Madrid14, Florida Institute of Technology15, Max Planck Society16
TL;DR: In this article, the authors present human-supervised multi-component decompositions, which include, when judged appropriate, a central point source, bulge, disk, and bar components.
Abstract: The Spitzer Survey of Stellar Structure in Galaxies (S^4G) is a deep 3.6 and 4.5 μm imaging survey of 2352 nearby (<40 Mpc) galaxies. We describe the S(^4)G data analysis pipeline 4, which is dedicated to two-dimensional structural surface brightness decompositions of 3.6 μm images, using GALFIT3.0. Besides automatic 1-component Sersic fits, and 2-component Sersic bulge + exponential disk fits, we present human-supervised multi-component decompositions, which include, when judged appropriate, a central point source, bulge, disk, and bar components. Comparison of the fitted parameters indicates that multi-component models are needed to obtain reliable estimates for the bulge Sersic index and bulge-to-total light ratio (B/T), confirming earlier results. Here, we describe the preparations of input data done for decompositions, give examples of our decomposition strategy, and describe the data products released via IRSA and via our web page (www.oulu.fi/astronomy/S4G_PIPELINE4/MAIN). These products include all the input data and decomposition files in electronic form, making it easy to extend the decompositions to suit specific science purposes. We also provide our IDL-based visualization tools (GALFIDL) developed for displaying/running GALFIT-decompositions, as well as our mask editing procedure (MASK_EDIT) used in data preparation. A detailed analysis of the bulge, disk, and bar parameters derived from multi-component decompositions will be published separately.
264 citations
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Kyle S. Dawson1, David J. Schlegel2, Christopher P. Ahn1, Scott F. Anderson3 +181 more•Institutions (51)
TL;DR: The Baryon Oscillation Spectroscopic Survey (BOSS) as discussed by the authors was designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large scale structure.
Abstract: The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large scale structure. BOSS uses 1.5 million luminous galaxies as faint as i=19.9 over 10,000 square degrees to measure BAO to redshifts z<0.7. Observations of neutral hydrogen in the Lyman alpha forest in more than 150,000 quasar spectra (g<22) will constrain BAO over the redshift range 2.15
263 citations
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Spanish National Research Council1, University of Zaragoza2, Clark University3, Pontifical Catholic University of Chile4, University of Michigan5, University of Chile6, Andrés Bello National University7, University of Santiago, Chile8, Kyoto University9, Vienna University of Technology10, United States Department of Agriculture11, University of Wisconsin-Madison12, University of Cincinnati13, University of Iowa14, Colorado School of Mines15, Universidad Pública de Navarra16, University of Toronto17, Aix-Marseille University18, Pacific Northwest National Laboratory19, University of Göttingen20, University of Tokyo21, University of Minnesota22, United States Department of Energy23, University of Jena24, Hebrew University of Jerusalem25, Centraalbureau voor Schimmelcultures26, Swedish University of Agricultural Sciences27, Swansea University28, Novozymes29
TL;DR: In this paper, a comparative genome analysis of C. subvermispora and P. chrysosporium was conducted to investigate the basis for selective ligninolysis.
Abstract: Efficient lignin depolymerization is unique to the wood decay basidiomycetes, collectively referred to as white rot fungi. Phanerochaete chrysosporium simultaneously degrades lignin and cellulose, whereas the closely related species, Ceriporiopsis subvermispora, also depolymerizes lignin but may do so with relatively little cellulose degradation. To investigate the basis for selective ligninolysis, we conducted comparative genome analysis of C. subvermispora and P. chrysosporium. Genes encoding manganese peroxidase numbered 13 and five in C. subvermispora and P. chrysosporium, respectively. In addition, the C. subvermispora genome contains at least seven genes predicted to encode laccases, whereas the P. chrysosporium genome contains none. We also observed expansion of the number of C. subvermispora desaturase-encoding genes putatively involved in lipid metabolism. Microarray-based transcriptome analysis showed substantial up-regulation of several desaturase and MnP genes in wood-containing medium. MS identified MnP proteins in C. subvermispora culture filtrates, but none in P. chrysosporium cultures. These results support the importance of MnP and a lignin degradation mechanism whereby cleavage of the dominant nonphenolic structures is mediated by lipid peroxidation products. Two C. subvermispora genes were predicted to encode peroxidases structurally similar to P. chrysosporium lignin peroxidase and, following heterologous expression in Escherichia coli, the enzymes were shown to oxidize high redox potential substrates, but not Mn2+. Apart from oxidative lignin degradation, we also examined cellulolytic and hemicellulolytic systems in both fungi. In summary, the C. subvermispora genetic inventory and expression patterns exhibit increased oxidoreductase potential and diminished cellulolytic capability relative to P. chrysosporium.
263 citations
Authors
Showing all 24784 results
Name | H-index | Papers | Citations |
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Didier Raoult | 173 | 3267 | 153016 |
Andrea Bocci | 172 | 2402 | 176461 |
Marc Humbert | 149 | 1184 | 100577 |
Carlo Rovelli | 146 | 1502 | 103550 |
Marc Besancon | 143 | 1799 | 106869 |
Jian Yang | 142 | 1818 | 111166 |
Josh Moss | 139 | 1019 | 89255 |
Maksym Titov | 139 | 1573 | 128335 |
Bernard Henrissat | 139 | 593 | 100002 |
R. D. Kass | 138 | 1920 | 107907 |
Stylianos E. Antonarakis | 138 | 746 | 93605 |
Jean-Paul Kneib | 138 | 805 | 89287 |
Brad Abbott | 137 | 1566 | 98604 |
Shu Li | 136 | 1001 | 78390 |
Georges Aad | 135 | 1121 | 88811 |