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Place-Making, Fire, and the Praxis of Becoming Angkor
No full textInternational audienceThis chapter examines the workings of the Angkorian Khmer state through the lens of place-making, manipulation of fire, and practice. To move beyond top-down or bottom-up perspectives, our study emphasizes how the actions of kings, elites, and commoners underwrote a general cohesion of the Angkorian state that lasted over a period of five centuries. Specifically, recent archaeological work shows the importance of Khmer place-making through both the veneration of monuments and intangible sites of memory dating back centuries and specialized high-temperature pyrotechnologies. We argue that the praxis of re-making the Angkorian landscape across their entire territories and specialized control of fire represent ritualized performance that was both broadly legible to its populations and provides a more dynamic view of polity creation relative to traditional models of centralization and coercio
Mining the time axis with TRON - I. Millisecond pulsars in Omega Centauri, Terzan 5, and 47 Tucanae detected through MeerKAT interferometric imaging
No full textInternational audienceMedium-time-scale (minutes to hours) radio transients are a relatively unexplored population. The wide field-of-view and high instantaneous sensitivity of instruments such as MeerKAT provides an opportunity to probe this class of sources, using image-plane detection techniques. We aim to systematically mine archival synthesis imaging data in order to search for medium-time-scale transients and variables that are not detected by conventional long-track image synthesis techniques. We deploy a prototype blind transient and variable search pipeline named Transient Radio Observations for Newbies. This processes calibrated visibility data, constructs high-time cadence images, performs a search for variability on multiple time-scales, and extracts light curves for detected sources. As proof of concept, we apply it to three MeerKAT observations of globular clusters, known to host transient or variable sources. We detect a previously known eclipsing MSP suspected to be a 'black widow' system, in the globular cluster Omega Centauri, with a light curve confirming the eclipsing nature of the emission. We detect a previously known 'red back' eclipsing MSP in the globular cluster Terzan 5. Using observations of the globular cluster 47 Tucanae, we detect two known millisecond pulsars (MSPs), and one previously reported MSP candidate, with hints of eclipsing behaviour
Decentering Migration Studies through Housing Studies - Migration-led urban renewal in French shrinking small towns
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Enigmatic carbon isotopic variability in the oceanic upper mantle
No full textInternational audienceUnraveling the origin(s) of carbon on Earth has remained challenging, not only because of the multiple isotopic fractionation episodes that may have occurred during planet formation processes but also because the end point of these processes, the current isotopic value of Earth’s deep carbon reservoirs remains poorly constrained. Here, we present carbon isotopic measurements on rare undegassed mid-ocean ridge basalts from the Pacific, Atlantic, and Arctic Oceans that have preserved the isotopic signature of their mantle source. We find that Earth’s present-day convecting upper mantle has variable δ 13 C value from ~−10 to −4‰, significantly different from the δ 13 C value of peridotitic diamonds and with the highest values being restricted to the Atlantic. Evidence for significant mantle heterogeneity contrasts with previous assumptions and its origin remains puzzling being uncorrelated with geochemical markers associated with either subduction and surficial recycling processes or lower mantle contributions. The data do not preclude other causes such as primordial mantle heterogeneity. We suggest that the δ 13 C value of the bulk silicate Earth may need to be revised
Propriétés asymptotiques de l'estimateur du maximum de vraisemblance pour des modèles markoviens cachés indexés par des arbres binaires
No full textInternational audienceWe consider hidden Markov models indexed by a binary tree where the hidden state space is a general metric space. We study the maximum likelihood estimator (MLE) of the model parameters based only on the observed variables. In both stationary and non-stationary regimes, we prove strong consistency and asymptotic normality of the MLE under standard assumptions. Those standard assumptions imply uniform exponential memorylessness prop- erties of the initial distribution conditional on the observations. The proofs rely on ergodic theorems for Markov chain indexed by trees with neighborhood-dependent functions.Nous considérons des modèles markoviens cachés indexés par un arbre binaire où l'espace des états cachés est un espace métrique général. Nous étudions l'estimateur du maximum de vraisemblance (MLE) des paramètres du modèle basé uniquement sur les variables observées. Dans les régimes stationnaires et non stationnaires, nous prouvons la consistance forte et la normalité asymptotique du MLE sous des hypothèses standards. Ces hypothèses standards impliquent des propriétés uniformes d'oubli exponentiel de la mémoire pour la distribution initiale conditionnelle aux observations. Les preuves reposent sur des théorèmes ergodiques pour des chaînes de Markov branchantes indexées par des arbres avec des fonctions dépendant du voisinage
Characterization of the impact of oxygen concentration on the alumina cloud surrounding a burning aluminum droplet
No full textInternational audienceThe high energetic density of aluminum makes it a relevant choice as an energetic additive in the propulsion field. Mainly added to solid fuels, its use improves the global performance of the rocket due to its high combustion temperature. Moreover, aluminum is gaining consideration as a potential clean energy carrier. Indeed, its availability, ease of transportation or capacity to recycle are characteristics that are sought after. During the combustion of an aluminum particle in the gas phase regime, aluminum reacts with the available oxygen in a region separate from the particle, resulting in the formation of alumina through a highly exothermic reaction. Upon formation, alumina instantly condenses into nanodroplets. These droplets can then coagulate or aggregate upon cooling, forming the primary condensed combustion products (CCPs). In the military or space explorations fields, characterizing these CCPs is essential, as it directly affects rocket efficiency through thermoacoustic oscillations or two-phase ejection losses. This characterization is also vital for aluminum recycling, as alumina must be recovered and reduced to form aluminum again. Therefore, assessing the characteristics of alumina around a burning aluminum droplet is of utmost importance. While numerical studies remain scarce and present discrepancies in the results, the methods developed allow for the non-intrusive determination of in situ alumina size, concentration, temperature and gaseous emission profiles during the combustion of a levitating aluminum droplet in a chosen environment. While results in the case of air have already been published, the impact of oxygen concentration of the combustion parameters needs to be understood. In this work, a light extinction method (LEM) combined with a modulated absorption emission (MAE) method is applied to the case of an aluminum droplet burning in an O2/Ar mixture at 1 bar. To grasp the impact of oxygen concentration, the results for a 21%O2/79%Ar(vol.) are compared to those for a 30%O2/70%Ar(vol.) mixture. The size, concentration and temperature profiles of alumina nanoparticles are obtained for a 70 micron diameter aluminum particle
Mixed genetic background better recapitulates developmental and psychiatric phenotypes and heterogeneity than inbred C57BL/6J mice
No full textPreclinical models of neurodevelopmental and psychiatric conditions often rely on inbred mouse strains like C57BL/6J (B6), which exhibit limited genetic and behavioral variability. This limitation hampers the modeling of phenotypic heterogeneity, characteristic of these conditions. Recent efforts have explored the use of multiple genetically diverse hybrid strains to address this. In this study, we examined whether one single mixed genetic mouse background, C57BL/6J;129S2/SvPas (B6;129), could simultaneously recapitulate behavioral variability and display improved phenotypes relevant to neurodevelopmental and psychiatric conditions. Compared to the inbred B6 strain, mixed B6;129 mice displayed enhanced sociability and self-grooming, two key discriminating parameters between the two mouse backgrounds and core features of such conditions, alongside a broader spectrum of individual behavioral variability. Although overall behavioral variability was comparable across backgrounds, B6;129 mice were less susceptible to the effects of chronic social isolation than their B6 counterparts.Together, these findings support that the B6;129 mixed background offers a more representative model of individual variability and behavioral traits associated with neurodevelopmental and psychiatric conditions, thereby enhancing its translational relevance in preclinical studies.</p
Novel lanthanide(III)/gallium(III) metallacrowns with appended visible-absorbing organic sensitizers for molecular near-infrared imaging of living cells
No full textInternational audienceOptical imaging of biological samples in the near-infrared (NIR) domain is of major interest for non-invasive experiments due to reduced light scattering, absorption and autofluorescence. Taking advantage of the maleimide moieties in the [Ln2Ga8(shi)8(mip)4] metallacrowns (MCs; shi = salicylhydroximate; mip = 5-maleimido-isophthalate; Ln = NdIII, GdIII, ErIII, YbIII and YIII), we appended visible-absorbing thiol-coumarin (C) sensitizers through a thiol-Michael addition click reaction, affording the functionalized [Ln2Ga8(shi)8(C-mip)4] MCs. By using this approach, the sensitization of NIR-emitting NdIII, ErIII and YbIII was achieved upon excitation in the visible range (λ = 420 nm) through the appended coumarins. NIR epifluorescence microscopy of living HeLa cells incubated with the NdIII derivative confirmed unambiguous detection of the signal arising from the F → I electronic transition in the range of 1050–1080 nm in the cells. These results demonstrate that the [Ln2Ga8(shi)8(mip)4] MC can be used as a versatile molecule for tuning the chemical and photophysical properties of the [Ln2Ga8] MC family
Gold-catalyzed synthesis of heterospirocycles for molecular diversity
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Ebola's Shadow on African Economies: FDI and Remittances
No full textThis paper investigates the impact of the Ebola epidemic on foreign direct investment (FDI) and remittance inflows across 28 African countries between 2000 and 2019. While existing literature highlights the economic costs of epidemics within affected countries, limited attention has been given to the broader financial repercussions-particularly on external financial flows and regional spillovers. This study addresses this gap by examining the dynamic responses of FDI and remittances to Ebola outbreaks using a local projection method (LPM) and validating the findings through system Generalized Method of Moments (GMM) to address endogeneity concerns. We construct a unique Ebola shock variable that captures both direct and indirect exposure, allowing for comparative analysis across affected countries, neighboring countries, and the broader region. The results reveal a sharp and persistent decline in FDI following Ebola outbreaks, especially in directly affected countries, driven by heightened uncertainty and investor risk aversion. In contrast, remittance inflows exhibit a counter-cyclical pattern, rising significantly in affected countries as diaspora communities respond to increased financial needs. Spillover effects are also evident: neighboring countries experience FDI losses but weaker remittance responses.</div