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La tradition de la peinture des lettrés et les poètes-peintres contemporains
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Znf687 recruits Brd4-Smrt complex to regulate gfi1aa during neutrophil development
No full textInternational audienceNeutrophils are key component of the innate immune system in vertebrates. Diverse transcription factors and cofactors act in a well-coordinated manner to ensure proper neutrophil development. Dysregulation of the transcriptional program triggering neutrophil differentiation is associated with various human hematologic disorders such as neutropenia, neutrophilia, and leukemia. In the current study we show the zinc finger protein Znf687 is a lineage-preferential transcription factor, whose deficiency leads to an impaired neutrophil development in zebrafish. Mechanistically, Znf687 functions as a negative regulator of gfi1aa, a pivotal modulator in terminal granulopoiesis, to regulate neutrophil maturation. Moreover, we found BRD4, an important epigenetic regulator, directly interacts with ZNF687 in neutrophils. Deficiency of brd4 results in similar defective neutrophil development as observed in znf687 mutant zebrafish. Biochemical and genetic analyses further reveal that instead of serving as a canonical transcriptional coactivator, Brd4 directly interacts and bridges Znf687 and Smrt nuclear corepressor on gfi1aa gene's promoter to exert transcription repression. In addition, the ZNF687-BRD4-SMRT-GFI1 transcriptional regulatory network is evolutionary conserved in higher vertebrate. Overall, our work indicates Znf687 and Brd4 are two novel master regulators in promoting terminal granulopoiesis
Stable isotopes show Homo sapiens dispersed into cold steppes ~45,000 years ago at Ilsenhöhle in Ranis, Germany
No full textInternational audienceThe spread of Homo sapiens into new habitats across Eurasia ~45,000 years ago and the concurrent disappearance of Neanderthals represents a critical evolutionary turnover in our species’ history. ‘Transitional’ technocomplexes, such as the Lincombian–Ranisian–Jerzmanowician (LRJ), characterize the European record during this period but their makers and evolutionary significance have long remained unclear. New evidence from Ilsenhöhle in Ranis, Germany, now provides a secure connection of the LRJ to H. sapiens remains dated to ~45,000 years ago, making it one of the earliest forays of our species to central Europe. Using many stable isotope records of climate produced from 16 serially sampled equid teeth spanning ~12,500 years of LRJ and Upper Palaeolithic human occupation at Ranis, we review the ability of early humans to adapt to different climate and habitat conditions. Results show that cold climates prevailed across LRJ occupations, with a temperature decrease culminating in a pronounced cold excursion at ~45,000–43,000 cal bp . Directly dated H. sapiens remains confirm that humans used the site even during this very cold phase. Together with recent evidence from the Initial Upper Palaeolithic, this demonstrates that humans operated in severe cold conditions during many distinct early dispersals into Europe and suggests pronounced adaptability
Un petit déjeuner au lupanar où comment Bodhidharma fut converti au taoïsme
No full textInternational audienceThis chapter provides an annotated translation of two anecdotes from the "Biographies of the Seven Perfected Patriarchs" Qizhen zushi liezhuan 七真祖師列傳, a hagiographic account in the vernacular language of the founding masters of Quanzhen Taoism 全真, the first surviving edition of which dates from 1893. It tells the story of how Bodhidharma was converted to Taoism by Liu Chuxuan 劉處玄 after he realised that Liu, who could cook cakes and boil water by the heat of his body alone, possessed a body of pure yang 陽, far superior to the still mortal bodies of Buddhist meditators, despite his apparently debauched conduct : it was in the brothel where Liu practiced sexual yoga that the Indian monk found him, initially convinced that he could easily win this rogue Taoist over to Buddhism. In the other anecdote, whose hero is his fellow student Hao Taigu 郝太古, we see their master Wang Chongyang 王重陽, the founder of Quanzhen, come to order Hao to give up immediately the silent meditation he has been inflicting on himself for several years. Such austerities could have no other effect than to exhale a "yin soul" 陰魄, fit only to be reincarnated or at best to rise to the status of "spectral immortal" (guixian 鬼仙). The lesson that can be drawn from these accounts, beyond the polemical assertion of the superiority of Taoists over Buddhists, is that the saint is far better off remaining self-cultivating in the midst of the world, close to defilements and passions, rather than sticking to solitary asceticism. This invitation to "accommodate one's enlightenment by mixing it with the vulgar" (hun su he guang 混俗和光), which contradicts the original message of Quanzhen Taoism, is reminiscent of many vernacular hagiographies extolling the prowess of eccentric masters and other filthy saints.Ce chapitre propose la traduction commentée de deux anecdotes figurant dans les « Biographies des patriarches les Sept parfaits » Qizhen zushi liezhuan 七真祖師列傳 un récit hagiographique en langue vulgaire consacré aux maîtres fondateurs du Taoïsme Quanzhen 全真, dont la première édition conservée date de 1893. On y raconte comment Bodhidharma fut converti au Taoïsme par Liu Chuxuan 劉處玄 pour avoir constaté que ce dernier, capable de cuire des galettes et de faire bouillir de l’eau par la seule chaleur de son corps, possédait un corps de yang 陽 pur, bien supérieur au corps encore mortel des méditants bouddhistes, et ce en dépit de sa conduite apparemment débauchée : c’est dans le bordel où Liu se livre au yoga sexuel que le moine indien l’a trouvé, d’abord convaincu de pouvoir facilement gagner au bouddhisme ce taoïste dévoyé. Dans l’autre anecdote, dont le héros est son condisciple Hao Taigu 郝太古, on voit leur maître Wang Chongyang 王重陽, le fondateur du Quanzhen, venir ordonner à Hao d'abandonner sur le champ la méditation silencieuse qu’il s’inflige depuis plusieurs années. De telles austérités ne sauraient avoir d’autre effet que de pouvoir exhaler une « âme yin » 陰魄, juste bonne à se réincarner ou au mieux s’élever au statut d' « immortel spectral » (guixian 鬼仙). La leçon qu’on peut tirer de ces récits, au-delà de l’affirmation polémique de la supériorité des taoïstes sur les bouddhistes, est que le saint fait bien mieux de rester se cultiver au sein du monde, proche des souillures et des passions, plutôt que de s’en tenir à l’ascèse solitaire. Cette invite à « accommoder ses lumières en les mêlant au vulgaire » (hun su he guang 混俗和光), en contradiction avec le message initial du taoïsme Quanzhen, rappelle en revanche bien des hagiographies vernaculaires vantant les prouesses des maîtres excentriques et autres saints crasseux
Polycyclic Aromatic Hydrocarbon Emission in the Central Regions of Three Seyferts and the Implication for Underlying Feedback Mechanisms
No full textInternational audienceWe analyze JWST Mid-Infrared Instrument/Medium Resolution Spectrograph integral field unit observations of three Seyferts from the Galactic Activity, Torus, and Outflow Survey (GATOS) and showcase the intriguing polycyclic aromatic hydrocarbon (PAH) and emission-line characteristics in regions of ∼500 pc scales over or around their active galactic nuclei (AGN). Combing the measurements and model predictions, we find that the central regions containing a high fraction of neutral PAHs with small sizes, e.g., those in ESO137-G034, are in highly heated environments, due to collisional shock heating, with hard and moderately intense radiation fields. Such environments are proposed to result in inhibited growth or preferential erosion of PAHs, decreasing their average size and overall abundance. We additionally find that the central regions containing a high fraction of ionized PAHs with large sizes, e.g., those in MCG-05-23-016, are likely experiencing severe photoionization because of the radiative effects from the radiative shock precursor besides the AGN. The severe photoionization can contribute to the ionization and further destruction of PAHs. Overall, different Seyferts, even different regions in the same galaxy, e.g., those in NGC 3081, can contain PAH populations of different properties. Specifically, Seyferts that exhibit similar PAH characteristics to ESO137-G034 and MCG-05-23-016 also tend to have similar emission-line properties to them, suggesting that the explanations for PAH characteristics of ESO137-G034 and MCG-05-23-016 may also apply generally. These results have promising application in the era of JWST, especially in diagnosing different (i.e., radiative and kinetic) AGN feedback modes
GATOS: missing molecular gas in the outflow of NGC 5728 revealed by JWST
No full textInternational audienceThe ionisation cones of NGC 5728 have a deficit of molecular gas based on millimetre observations of CO (2-1) emission. Although photoionisation from the active nucleus may lead to suppression of this transition, warm molecular gas can still be present. We report the detection of eight mid-infrared rotational H2 lines throughout the central kiloparsec, including the ionisation cones, using integral field spectroscopic observations with JWST/MIRI MRS. The H2 line ratios, characteristic of a power-law temperature distribution, indicate that the gas is warmest where it enters the ionisation cone through disk rotation, suggestive of shock excitation. In the nucleus, where the data can be combined with an additional seven ro-vibrational H2 transitions, we find that moderate velocity (30 km s‑1) shocks in dense (105 cm‑3) gas, irradiated by an external UV field (G0 = 103), do provide a good match to the full set. The warm molecular gas in the ionisation cone that is traced by the H2 rotational lines has been heated to temperatures > 200 K. Outside of the ionisation cone the molecular gas kinematics are undisturbed. However, within the ionisation cone, the kinematics are substantially perturbed, indicative of a radial flow, but one that is quantitatively different from the ionised lines. We argue that this outflow is in the plane of the disk, implying a short 50 pc acceleration zone up to speeds of about 400 km s‑1 followed by an extended deceleration over ∼700 pc where it terminates. The deceleration is due to both the radially increasing galaxy mass, and mass-loading as ambient gas in the disk is swept up
CON-quest. II. Spatially and spectrally resolved HCN/HCO<sup>+</sup> line ratios in local luminous and ultraluminous infrared galaxies
No full textInternational audienceContext. Nuclear regions of ultraluminous and luminous infrared galaxies (U/LIRGs) are powered by starbursts and/or active galactic nuclei (AGNs). These regions are often obscured by extremely high columns of gas and dust. Molecular lines in the submillimeter windows have the potential to determine the physical conditions of these compact obscured nuclei (CONs). Aims: We aim to reveal the distributions of HCN and HCO+ emission in local U/LIRGs and investigate whether and how they are related to galaxy properties. Methods: Using the Atacama Large Millimeter/submillimeter Array (ALMA), we have conducted sensitive observations of the HCN J = 3−2 and HCO+J = 3−2 lines toward 23 U/LIRGs in the local Universe (z < 0.07) with a spatial resolution of ∼0.3″ (∼50−400 pc). Results: We detected both HCN and HCO+ in 21 galaxies, only HCN in one galaxy, and neither in one galaxy. The global HCN/HCO+ line ratios, averaged over scales of ∼0.5−4 kpc, range from 0.4 to 2.3, with an unweighted mean of 1.1. These line ratios appear to have no systematic trend with bolometric AGN luminosity or star formation rate. The line ratio varies with position and velocity within each galaxy, with an average interquartile range of 0.38 on a spaxel-by-spaxel basis. In eight out of ten galaxies known to have outflows and/or inflows, we found spatially and kinematically symmetric structures of high line ratios. These structures appear as a collimated bicone in two galaxies and as a thin spherical shell in six galaxies. Conclusions: Non-LTE analysis suggests that the high HCN/HCO+ line ratio in outflows is predominantly influenced by the abundance ratio. Chemical model calculations indicate that the enhancement of HCN abundance in outflows is likely due to high-temperature chemistry triggered by shock heating. These results imply that the HCN/HCO+ line ratio can aid in identifying the outflow geometry when the shock velocity of the outflows is sufficiently high to heat the gas
The MeerKAT Absorption Line Survey (MALS) Data Release. I. Stokes I Image Catalogs at 1–1.4 GHz
No full textInternational audienceThe MeerKAT Absorption Line Survey (MALS) has observed 391 telescope pointings at the L band (900–1670 MHz) at δ ≲ +20°. We present radio continuum images and a catalog of 495,325 (240,321) radio sources detected at a signal-to-noise ratio (S/N) > 5 over an area of 2289 deg2 (1132 deg2) at 1006 MHz (1381 MHz). Every MALS pointing contains a central bright radio source (S 1 GHz ≳ 0.2 Jy). The median spatial resolution is 12″ (8″). The median rms noise away from the pointing center is 25 μJy beam‑1 (22 μJy beam‑1) and is within ∼15% of the achievable theoretical sensitivity. The flux density scale ratio and astrometric accuracy deduced from multiply observed sources in MALS are <1% (8% scatter) and 1″, respectively. Through comparisons with NVSS and FIRST at 1.4 GHz, we establish the catalog's accuracy in the flux density scale and astrometry to be better than 6% (15% scatter) and 0.″8, respectively. The median flux density offset is higher (9%) for an alternate beam model based on holographic measurements. The MALS radio source counts at 1.4 GHz are in agreement with literature. We estimate spectral indices (α) of a subset of 125,621 sources (S/N > 8), confirm the flattening of spectral indices with decreasing flux density, and identify 140 ultra-steep-spectrum (α < ‑1.3) sources as prospective high-z radio galaxies (z > 2). We have identified 1308 variable and 122 transient radio sources comprising primarily active galactic nuclei that demonstrate long-term (26 yr) variability in their observed flux densities. The MALS catalogs and images are publicly available at https://mals.iucaa.in
X-ray observations of Blueberry galaxies
No full textInternational audienceContext. Compact star-forming galaxies were dominant galaxy types in the early Universe. Blueberry galaxies (BBs) represent their local analogues, being very compact and having intense star formation. Aims. Motivated by high X-ray emission recently found in other analogical dwarf galaxies, called Green Peas, we probed the X-ray properties of BBs to determine if their X-ray emission is consistent with the empirical laws for star-forming galaxies. Methods. We performed the first X-ray observations of a small sample of BBs with the XMM-Newton satellite. Spectral analysis for detected sources and upper limits measured via Bayesian-based analysis for very low-count measurements were used to determine the X-ray properties of our galaxy sample. Results. Clear detection was obtained for only two sources, with one source exhibiting an enhanced X-ray luminosity to the scaling relations. For the remaining five sources, only an upper limit was constrained, suggesting BBs to be rather underluminous as a whole. Our analysis shows that the large scatter cannot be easily explained by the stochasticity effects. While the bright source is above (and inconsistent with) the expected distribution at almost the 99% confidence level, the upper limits of the two sources are below the expected distribution. Conclusions. These results indicate that the empirical relations between the star formation rate, metallicity, and X-ray luminosity might not hold for BBs with uniquely high specific star formation rates. One possible explanation could be that the BBs may not be old enough to have a significant X-ray binary population. The high luminosity of the only bright source can then be caused by an additional X-ray source, such as a hidden active galactic nucleus or more extreme ultraluminous X-ray sources
Ingénierie des électrolytes via de nouveaux sels et additifs pour les solutions aqueuses de stockage d'énergie
No full textLi-ion batteries are the primary power source for portable electronics and electric vehicles, offering a high energy density of up to 400 Wh kg−1. However, the use of flammable and toxic organic electrolytes in these batteries poses significant sustainability challenges. Consequently, research is now focused on developing alternative battery devices using resource-abundant and cost-efficient materials. Aqueous alkaline-metal batteries and aqueous zinc-ion batteries are emerging as safer and more sustainable options. Water, being non-flammable and cost-effective, offers several advantages over organic electrolytes, but its reactive nature and narrow electrochemical stability window (ESW) of 1.23 V present challenges. Electrolyte engineering, employing strategies such as super-concentration, dilution with organic solvents, and additives, has been crucial in addressing these challenges. However, water reactivity remains an issue, specifically at the anode where it competes with ion (lithium) intercalation or metal (zinc) striping and plating, for instance.Amino acids have been investigated as additives to modulate the hydrogen bonding network of water and thus affect the kinetics of water splitting. While some promising electrolytes were developed, they showed poor cycling performance in full Li-ion cells. However, certain amino acids, like aspartic acid (Asp) and glutamic acid (Glu), were found to effectively buffer acid/base dynamics and sustain H3O+ reduction at high current densities. This study highlights the interplay between pH, pKa, and hydrogen evolution reaction (HER) kinetics, showing the potential of amino acids as tools for exploring this relationship. Next, a new approach for designing salts for aqueous battery electrolytes is examined, by combining chaotropic ions such as guanidium cations (Gdm+) with bis(trifluoromethanesulfonyl)imide anions (TFSI-). The novel GdmTFSI salt disrupts the hydrogen bonding network of water, extending the ESW by 0.25 V compared to LiTFSI solutions at the same concentrations. Building on idea of designing new salts to solve the various issues of aqueous electrolytes, zinc oligoether salts with varying chain lengths were synthesized and used as additives in zinc-ion batteries. These salts, added to a 2 M ZnSO4(aq) solution, increased the cycle time of Zn symmetric cells from 200 to over 1000 hours by improving the morphology of Zn electrodeposition and preventing dendrite growth. The best-performing additive, Zn(MEEA)2, was added to a patented electrolyte containing urea for Zn || MnO2 full cells, increasing cycle life threefold compared to the electrolyte without the additive. Perylene-3,4,9,10-tetracarboxylic acid diimide (PTCDI) was evaluated as a redox-active organic material (ROM) for aqueous Li-ion batteries (ALIBs). Despite its high conductivity and low solubility in water, PTCDI had not been previously used in aqueous electrolytes for Li-ion batteries. Using various techniques such as ex-situ IR, ex-situ XRD, and EQCM, the charge compensation mechanism was determined. The concentration of the salt and anion choice were found to be crucial for long-term stability, where a 1 mol/kg LiTFSI(aq) was able to retain 90% capacity after 1000 cycles at a c-rate of 1C, which compares very well to other examples of PTCDI in the literature.This thesis provides multiple solutions to the challenges faced by aqueous batteries through electrolyte engineering. Future work can build on these findings to further probe the fundamentals of water splitting, prevent dendrite formation in Zn-metal batteries, and explore the potential of redox-active organic materials to move away from super-concentrated aqueous electrolytes.Les batteries Li-ion sont essentielles pour les appareils électroniques portables et les véhicules électriques, offrant une densité d'énergie élevée jusqu'à 400 Wh kg−1. Cependant, leurs électrolytes organiques inflammables et toxiques posent des défis de durabilité. La recherche se tourne donc vers des batteries alternatives avec des matériaux abondants et économiques. Les batteries aqueuses à base de métaux alcalins et à ions zinc apparaissent comme des options plus sûres et durables. L'eau, non inflammable et économique, offre des avantages, mais sa réactivité et sa fenêtre de stabilité électrochimique (FSE) étroite de 1,23 V posent des défis. L'ingénierie des électrolytes, avec des stratégies comme la super-concentration, la dilution avec des solvants organiques et les additifs, est cruciale pour relever ces défis. Cependant, la réactivité de l'eau reste problématique, surtout à l'anode où elle concurrence l'intercalation des ions (lithium) ou le stripping et le plating du métal (zinc). Les acides aminés ont été étudiés comme additifs pour moduler les liaisons hydrogène de l'eau et affecter la cinétique de la dissociation de l'eau. Certains électrolytes prometteurs ont montré de faibles performances de cyclage dans les cellules Li-ion complètes. Cependant, certains acides aminés, comme l'acide aspartique (Asp) et l'acide glutamique (Glu), tamponnent efficacement la dynamique acide/base et maintiennent la réduction de H3O+ à des densités de courant élevées. Cette étude met en évidence l'interaction entre le pH, le pKa et la cinétique de la réaction d'évolution de l'hydrogène (HER), montrant le potentiel des acides aminés pour explorer cette relation. Une nouvelle approche pour concevoir des sels pour les électrolytes de batteries aqueuses combine des ions chaotropes tels que les cations guanidinium (Gdm+) avec les anions bis(trifluorométhanesulfonyl)imide (TFSI-). Le nouveau sel GdmTFSI perturbe les liaisons hydrogène de l'eau, augmentant la FSE de 0,25 V par rapport aux solutions de LiTFSI aux mêmes concentrations. Pour résoudre les problèmes des électrolytes aqueux, des sels d'oligoéthers de zinc avec des longueurs de chaîne variables ont été synthétisés et utilisés comme additifs dans les batteries à ions zinc. Ces sels, ajoutés à une solution de 2 M ZnSO4(aq), ont augmenté le temps de cycle des cellules symétriques Zn de 200 à plus de 1000 heures en améliorant la morphologie de l'électrodéposition de Zn et en empêchant la croissance des dendrites. L'additif le plus performant, Zn(MEEA)2, ajouté à un électrolyte breveté contenant de l'urée pour les cellules Zn || MnO2 complètes, a triplé la durée de vie des cycles par rapport à l'électrolyte sans l'additif. L'acide perylène-3,4,9,10-tétracarboxylique diimide (PTCDI) a été évalué comme matériau organique redox-actif (ROM) pour les batteries Li-ion aqueuses (ALIB). Malgré sa haute conductivité et sa faible solubilité dans l'eau, le PTCDI n'avait pas été utilisé dans les électrolytes aqueux pour les batteries Li-ion. En utilisant diverses techniques telles que l'IR ex-situ, la DRX ex-situ et l'EQCM, le mécanisme de compensation de charge a été déterminé. La concentration du sel et le choix de l'anion se sont révélés cruciaux pour la stabilité à long terme, où une solution de 1 mol/kg de LiTFSI(aq) a conservé 90 % de sa capacité après 1000 cycles à un taux de charge de 1C, ce qui est très favorable comparé à d'autres exemples de PTCDI dans la littérature. Cette thèse propose plusieurs solutions aux défis des batteries aqueuses grâce à l'ingénierie des électrolytes. Les travaux futurs peuvent approfondir les fondamentaux de la dissociation de l'eau, prévenir la formation de dendrites dans les batteries à métal zinc, et explorer le potentiel des matériaux organiques redox-actifs pour s'éloigner des électrolytes aqueux super-concentrés