HAL Université de Toulouse, et Toulouse INP
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Characterizing sonochemical activity and cavitation cloud in a flow-through sonoreactor
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Quantifying sulfur speciation in magmatic-hydrothermal fluids
No full textQuantitative knowledge of sulfur speciation in the fluid phase is key to understanding sulfur degassing from magmas and its transfer along with metals by fluids across the lithosphere. Farsang and Zajacz (1) recently reported new sulfur speciation data using Raman spectroscopy measurements on aqueous H2SO4-NaCl(-KCl) solutions trapped as synthetic fluid inclusions in quartz at 875 °C and 2 kbar under variable redox conditions. They interpreted the data by dominant SO2(aq) and HS-, along with subordinate H2S(aq), whereas the di-and trisulfur radical ions, [S3•]- and [S2•]-, reported in aqueous fluids both in nature and experiment to at least 700 °C and 15 kbar (2-5) , were undetectable in Raman nonresonant spectra 1 . On the basis of thermochemical calculations that returned negligible HS- and large [S3•]- concentrations at their experimental conditions, the authors claimed that the published [S3•]- and HS- thermodynamic data were incorrect and that the major species controlling both sulfur and gold transport in hydrothermal-magmatic fluids is the HS- anion. Here I demonstrate that their conclusions stem from the use of inconsistent thermodynamic data and incorrect Raman spectra assignments. Thus, ref. 1 provides no grounds for questioning the validity of the thermodynamic properties of HS- and [S3•]- or of their metal complexes in the fluids of the Earth's crust
Surveying the Whirlpool at Arcseconds with NOEMA (SWAN): II. Survey design and observations
No full textInternational audienceWe present Surveying the Whirlpool at Arcseconds with NOEMA (SWAN), a high-resolution, high-sensitivity survey to map molecular lines in the 3 mm band in M51 (the Whirlpool galaxy). SWAN has obtained the largest high-sensitivity map (∼5 × 7 kpc2) of N2H+ emission at ∼cloud-scale resolution (3″ ∼ 125 pc) in an external galaxy to date. Here, we describe the observations and data reduction of ∼214 hours of interferometric data from the Northern Extended Millimetre Array (NOEMA) and ∼55 hours of tailored new observations with the 30m telescope of the Institut de radioastronomie millimétrique (IRAM), as well as the combination of these NOEMA and new IRAM-30m observations with ∼14 hours of archival IRAM-30m observations. We detect widespread emission from nine molecular transition lines. The J = 1 ‑ 0 transitions of the CO isotopologs 13CO and C18O are detected at high significance across the full observed field of view (FoV). HCN(1‑0), HNC(1‑0), HCO+(1‑0), and N2H+(1‑0) are detected in the center, molecular ring, and spiral arms of the galaxy, while the shock tracer HNCO(4‑3) and (5‑4) and PDR tracer C2H(1‑0) are detected in the central ∼1 kpc and molecular ring only. For most of the lines that we detect, average line ratios with respect to 12CO are increased by up to a factor of ∼3 in the central 1 kpc, where an active galactic nucleus and its low-inclination outflow are present, compared to the disk. Line ratios between CO isotopologs show less variation across the SWAN FoV. Across the full SWAN FoV, 13CO, C18O, HCN, HNC, HCO+ and N2H+ are 8±22, 29±76, 17±35, 37±510, 26±53 and 63±3810 times fainter than 12CO, respectively, in pixels where each line is significantly detected. Although we observe variations in line ratios between larger-scale environments like the center and disk of M51, the scatter within each environment also indicates the influence of smaller-scale processes. The ability to measure these effects is only possible thanks to the high resolution and high sensitivity of the SWAN dataset across multiple environments. This provides the sharpest view of these molecular transitions over the largest physical area ever captured in an external galaxy
Landscape heterogeneity and pesticide reduction favor predation, but also grape infestation by Lobesia botrana
No full textInternational audienceBiological pest control is a major ecosystem service and is known to depend on landscape heterogeneity. The composition and configuration of landscapes can affect natural enemy communities, trophic interactions, and pest density within agroecosystems. However, local agricultural management can interfere with natural enemy activity, so the positive effects of landscape heterogeneity may be disrupted by farming practices. Here, we studied the influence of landscape context and management options on the biological control of Lobesia botrana , one of the main insect pests of grapes. We focused on two complementary measures: predation rates, which reflect part of biological control potential, and plant damage, which reflects pest density and the associated infestation. We used a set of sentinel prey (eggs, caterpillars, pupae) to quantify predation rates across different developmental stages of the pest. The study was carried out in a landscape‐scale experimental set‐up consisting of 38 vineyards in Southwestern France. Using structural equation models, we show that predation rates on sentinel prey were affected by both landscape heterogeneity and local management practices. Higher pest predation rates were observed in landscapes with smaller vineyards and in vineyards with low applications of synthetic pesticides. We observed limited relationships between predation rates and grape infestation levels. However, our results suggest that predation rates at the pest pupae stage are significantly shaping infestation levels. Additionally, pest damage in spring and summer was primarily influenced by the intensity of local pesticide use and the grass cover in the field and exacerbated by the decreasing size of vineyards, while semi‐natural habitats had no effect on pest damage. We conclude that links between L. botrana infestation and biological control potential appear tenuous in our study region. This is likely due to the high local management intensity, as evidenced by the negative association observed between pesticide applications and predation rates. Nevertheless, both predation and infestation respond to landscape or field heterogeneity and pesticide use. Reducing the use of pesticides should be combined with multi‐scale diversification measures at field and landscape levels to amplify the predation potential
Straight from the Horse’s Mouth: Timing and Zoogeography of Domesticated Horse Arrivals in Mongolia and China
No full textInternational audienceThe timing, geographical pathways, and earliest uses for horses (Equus caballus) in East Asia have long been a scientific puzzle vigorously debated by scholars with different backgrounds across diverse disciplinary fields. Over the past two decades, a wide range of high-resolution evidence has been presented documenting the multi-regional dispersion of domesticated horses, but questions still abound, especially in the eastern regions of Eurasia. This study provides a rigorous critique of this body of evidence and advances hypotheses as to when and where domesticated horses first arrived in Mongolia and China. We present the earliest ancient DNA evidence for the DOM2 genetic lineage of modern domesticated horses in Mongolia and evaluate a comprehensive dataset of radiocarbon dates for East Asian domesticated horses using a Bayesian statistical approach that is powerful but seldom utilized by archaeologists. Our genetic and chronological evidence demonstrates that horses far to the east in Mongolia, interred in monumental prone burial contexts, were domesticated and contemporaneous with the earliest horses documented in western regions of Mongolia and Xinjiang. These results both complicate and clarify major questions related to the occurrence of domesticated horses within the greater region and help to explain the development of horse culture(s) and knowledge on the eastern steppe and at the Late Shang capital of Yinxu
The lamprey habenula provides an extreme example for the temporal regulation of asymmetric development
No full textInternational audienceBy their phylogenetic position and their marked epithalamic asymmetries, lampreys are relevant models for understanding the formation and evolution of this trait across vertebrates. In this study, we use a transcriptomic approach to identify novel signature markers to characterize the highly asymmetric, bipartite organization of habenulae in lampreys. Lamprey habenulae are subdivided into two complementary subdomains related, respectively, to the lateral/ventral and the medial/dorsal habenulae of jawed vertebrates: a dorsal, right-restricted subdomain and a bilateral subdomain that includes the left habenula as well as its ventral right counterpart. Analysis of the formation of the lamprey habenula at prolarval and larval stages using a combination of morphological, immunohistochemical, and in situ hybridization approaches highlights a marked asymmetric temporal regulation. The dorsal right subdomain forms and already expresses all identified signature markers in prolarval stages. In contrast, the left and ventral right subdomain appears significantly later, with the first indication of neuronal identity elaboration in these territories being observed in larval stages. As in gnathostomes, Wnt signaling may be involved in the regulation of this unique, asymmetric mode of development, since β-catenin shows asymmetric and highly dynamic nuclear distributions both in neural progenitors and differentiated neuronal precursors of the two habenular subdomains. These data confirm the importance of lampreys to unravel the developmental logic underlying the recurrence and variation of habenular asymmetries in vertebrates and pave the way for future functional analyses
General reproducing properties in RKHS with application to derivative and integral operators
No full textIn this paper, we consider the reproducing property in Reproducing Kernel Hilbert Spaces (RKHS). We establish a reproducing property for the closure of the class of combinations of composition operators under minimal conditions. This allows to revisit the sufficient conditions for the reproducing property to hold for the derivative operator, as well as for the existence of the mean embedding function. These results provide a framework of application of the representer theorem for regularized learning algorithms that involve data for function values, gradients, or any other operator from the considered class.Dans cet article, nous considérons la propriété reproduisante dans les espaces de Hilbert à noyaux reproduisants (RKHS). Nous établissons une propriété de reproduction pour l'adhérence de la classe des combinaisons d'opérateurs de composition sous des conditions minimales. Cela nous permet de revisiter les conditions suffisantes pour que la propriété de reproduction soit valable pour l'opérateur dérivé, ainsi que pour l'existence de la fonction mean embedding. Ces résultats donnent un cadre d'application du théorème du représentant pour les algorithmes d'apprentissage régularisés qui impliquent des données sur les valeurs de fonctions, les gradients ou tout autre opérateur de la classe considérée
Grand témoin. De la santé par l’alimentation (au plaidoyer) pour une santé globale par l’alimentation: Poser les enjeux sur les liens santé-alimentation-environnement
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Poster: A microarchitectural signals analysis platform to craft Hardware Security Counters
No full textInternational audienceDetecting malicious software or hardware behavior during the operation of a computer system requires observables from one or more abstraction layers of the system. However, this abstraction tends to limit the ability to detect behavioral deviations, especially for attack classes that exploit vulnerabilities very close to the target hardware. Conversely, too low a level of abstraction tends to significantly increase the complexity of the system model, and therefore poses a number of difficulties for the extraction and selection of relevant observables for a given class of attack.In particular, processor performance counters have been used as an indirect means of observing microarchitecture behavior and detecting software attempting to exploit hardware vulnerabilities. In order to improve the various detection methods, we propose the construction of hardware metrics designed from the outset for security, by studying the correlation between signals from the microarchitecture and the various classes of attack in the literature, targeting both usual and industrial systems. By extension, this work aims to detect attacks originating from hardware Trojans, the latter having the effect of changing the behavior of a given microarchitecture