424 research outputs found

    A Census of Sub-kiloparsec Resolution Metallicity Gradients in Star-forming Galaxies at Cosmic Noon from HST Slitless Spectroscopy

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    We present the hitherto largest sample of gas-phase metallicity radial gradients measured at sub-kpc resolution in star-forming galaxies in the redshift range of z ∈ [1.2, 2.3]. These measurements are enabled by the synergy of slitless spectroscopy from the Hubble Space Telescope near-infrared channels and the lensing magnification from foreground galaxy clusters. Our sample consists of 76 galaxies with stellar mass ranging from 10⁷ to 10Âč⁰ M_⊙, an instantaneous star formation rate in the range of [1, 100] M_⊙ yr⁻Âč, and global metallicity [1/12, 2] of solar. At a 2σ confidence level, 15/76 galaxies in our sample show negative radial gradients, whereas 7/76 show inverted gradients. Combining ours and all other metallicity gradients obtained at a similar resolution currently available in the literature, we measure a negative mass dependence of Δlog(O/H)/ Δr [dex kpc⁻Âč] = (−0.020 ± 0.007) + (−0.016 ± 0.008) log(M_∗/10^(9.4) M_⊙), with the intrinsic scatter being σ = 0.060 ± 0.006 over 4 orders of magnitude in stellar mass. Our result is consistent with strong feedback, not secular processes, being the primary governor of the chemostructural evolution of star-forming galaxies during the disk mass assembly at cosmic noon. We also find that the intrinsic scatter of metallicity gradients increases with decreasing stellar mass and increasing specific star formation rate. This increase in the intrinsic scatter is likely caused by the combined effect of cold-mode gas accretion and merger-induced starbursts, with the latter more predominant in the dwarf mass regime of M∗ â‰Č 10âč M_⊙

    Tempo and Pattern of Avian Brain Size Evolution

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    Relative brain sizes in birds can rival those of primates, but large-scale patterns and drivers of avian brain evolution remain elusive. Here, we explore the evolution of the fundamental brain-body scaling relationship across the origin and evolution of birds. Using a comprehensive dataset sampling> 2,000 modern birds, fossil birds, and theropod dinosaurs, we infer patterns of brain-body co-variation in deep time. Our study confirms that no significant increase in relative brain size accompanied the trend toward miniaturization or evolution of flight during the theropod-bird transition. Critically, however, theropods and basal birds show weaker integration between brain size and body size, allowing for rapid changes in the brain-body relationship that set the stage for dramatic shifts in early crown birds. We infer that major shifts occurred rapidly in the aftermath of the Cretaceous-Paleogene mass extinction within Neoaves, in which multiple clades achieved higher relative brain sizes because of a reduction in body size. Parrots and corvids achieved the largest brains observed in birds via markedly different patterns. Parrots primarily reduced their body size, whereas corvids increased body and brain size simultaneously (with rates of brain size evolution outpacing rates of body size evolution). Collectively, these patterns suggest that an early adaptive radiation in brain size laid the foundation for subsequent selection and stabilization

    Mémoire de Jean-Baptiste Colbert à Louis XIV (roi de France) concernant l'établissement du Conseil royal des finances, daté de 1661

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    Mémoire de Jean-Baptiste Colbert à Louis XIV (roi de France) concernant l'établissement du Conseil royal des finances, daté de 1661. In: Lettres, instructions et mémoires de Colbert, publiées par Pierre Clément. Tome II. Ire partie. Finances, impÎts, monnaies. Paris : Imprimerie impériale, 1863. pp. 201-202

    Lettre de Jean-Baptiste Colbert (contrÎleur général des finances) à Louis XIV (roi de France) datée du 16 mai 1670, à Paris

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    Lettre de Jean-Baptiste Colbert (contrÎleur général des finances) à Louis XIV (roi de France) datée du 16 mai 1670, à Paris. In: Lettres, instructions et mémoires de Colbert, publiées par Pierre Clément. Tome II. Ire partie. Finances, impÎts, monnaies. Paris : Imprimerie impériale, 1863. p. 273

    Lettre de Jean-Baptiste Colbert (contrÎleur général des finances) à Louis XIV (roi de France) datée du 14 août 1673, à Sceaux

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    Lettre de Jean-Baptiste Colbert (contrÎleur général des finances) à Louis XIV (roi de France) datée du 14 août 1673, à Sceaux. In: Lettres, instructions et mémoires de Colbert, publiées par Pierre Clément. Tome II. Ire partie. Finances, impÎts, monnaies. Paris : Imprimerie impériale, 1863. pp. 237-238

    Lettre de Jean-Baptiste Colbert (contrÎleur général des finances) à Louis XIV (roi de France) datée du 22 mai 1670, à Paris

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    Lettre de Jean-Baptiste Colbert (contrÎleur général des finances) à Louis XIV (roi de France) datée du 22 mai 1670, à Paris. In: Lettres, instructions et mémoires de Colbert, publiées par Pierre Clément. Tome II. Ire partie. Finances, impÎts, monnaies. Paris : Imprimerie impériale, 1863. p. 228

    Lettre de Jean-Baptiste Colbert (ministre d'Etat) à Louis XIV (roi de France) datée du 28 septembre 1665

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    Lettre de Jean-Baptiste Colbert (ministre d'Etat) à Louis XIV (roi de France) datée du 28 septembre 1665. In: Lettres, instructions et mémoires de Colbert, publiées par Pierre Clément. Tome II. Ire partie. Finances, impÎts, monnaies. Paris : Imprimerie impériale, 1863. pp. 210-211

    Lettre de Jean-Baptiste Colbert (secrétaire d'Etat de la Marine et de la Maison du roi) à Desgranges (consul à Lisbonne) datée du 04 décembre 1671, à Saint-Germain-en-Laye

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    Lettre de Jean-Baptiste Colbert (secrétaire d'Etat de la Marine et de la Maison du roi) à Desgranges (consul à Lisbonne) datée du 04 décembre 1671, à Saint-Germain-en-Laye. In: Lettres, instructions et mémoires de Colbert, publiées par Pierre Clément. Tome II. IIe partie. Industrie, commerce. Paris : Imprimerie impériale, 1863. pp. 638-639

    Lettre de Jean-Baptiste Colbert (contrÎleur général des finances) à Louis XIV (roi de France) datée du 26 mai 1674, à Paris

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    Lettre de Jean-Baptiste Colbert (contrÎleur général des finances) à Louis XIV (roi de France) datée du 26 mai 1674, à Paris. In: Lettres, instructions et mémoires de Colbert, publiées par Pierre Clément. Tome II. Ire partie. Finances, impÎts, monnaies. Paris : Imprimerie impériale, 1863. pp. 244-245
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