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Économie politique des missions : perspectives depuis l’Amérique du Sud autochtone: Introduction
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Variations en anthropologie (&) linguistique offertes à Aurore Monod Becquelin ; 2 : Orée du jour, lisières de la nuit...
No full textInternational audienceDans ce recueil, un ensemble d'anthropologues et de linguistes explore de façon innovante la notion de « frontière épaisse » et les arcanes de l'anthropologie de la nuit. À partir d'une connaissance approfondie de terrains situés aux quatre coins du monde, les contributeurs s'inspirent de l'œuvre de la dédicataire de l'ouvrage, Aurore Monod Becquelin, figure pionnière de l'anthropologie américaniste et cheville ouvrière du développement de l'ethnolinguistique en France. Élaborée sous son impulsion, la notion de « frontière épaisse » invite à considérer les frontières entre catégories comme sujettes à des phases ou états de transitions divers, hétérogènes et productifs de sens. Elle s'avère pertinente pour raffiner l'étude d'une grande variété de domaines, qu'il s'agisse d'espaces, de temps, d'états de la vie et du monde, ou encore du savoir. Dans le présent volume, ce sont des états de guerre et de paix, des divisions territoriales, des cosmologies inversant l'intérieur et l'extérieur, mais aussi des expressions du visible et de l'invisible qui sont scrutées au prisme de cette notion. Le second volet, consacré à l'anthropologie de la nocturnité, émane en partie du précédent puisqu'il interroge la nuit – souvent négligée des anthropologues endormis – non pas comme un état stable en simple alternance avec le jour mais comme un lieu de propriétés particulières pouvant déborder l'obscur et surgir en plein jour, bouleversant les frontières communément reconnues. Renversant le primat trop systématiquement accordé à une perspective diurne, le volume propose de nouvelles explorations, toujours sérieuses, parfois ludiques, de la vie nocturne : dans l'œuvre de Shakespeare et chez les chamanes de l'obscurité, chez les adeptes de l'hypnose, les guerriers nyctophyles ou les saintes en voie de métamorphose. Il y est question de l'apparition de l'éclairage artificiel dans des sociétés traditionnelles, ou encore de savoirs poétiques émergeant de la nuit
Les tombes a mobilier germanique dans le contexte funéraire urbain de l'Illyricum du Nord à l'époque des Grandes Migrations.
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A coral microatoll record of sea-level rise, interseismic deformation, and El Niño in La Union, Philippines since 1906 CE
No full textInternational audienceRelative sea level (RSL) along western Luzon is influenced by climate change, tectonic deformation, and the El Nino-Southern Oscillation. Long, high-resolution records of past changes in sea level and land level are crucial to distinguish these contributions for forecasting future RSL or identifying tectonic hazards. Coral microatolls are invaluable proxies for reconstructing RSL, but their interpretation relies on understanding how short-and longterm changes are recorded in the coral skeleton. We analyzed growth bands from 1906 to 2018 CE of a Porites microatoll from Balaoan, La Union, Philippines, using X-rays of vertical cross sections. The microatoll's surface morphology, annual banding, and growth history reveal RSL rise during its lifetime punctuated by 17 diedowns. Coral diedowns generally coincide with low water near the site, often resulting from El Nino events. Excluding eroded sections, 10 of the 11 strongest El Ninos since 1918 produced a diedown. Similarly, excluding a diedown caused by the coral tilting, 10 of the 12 preserved diedowns exceeding 3 mm in amplitude occurred during strong El Ninos. Between 1948 and 2018 CE, RSL rose at 1.3 +/- 1.8 mm/yr (2 sigma). Comparing sea-level rates from satellite altimetry and RSL from the coral, we estimate vertical land motion at-0.1 +/- 12.1 mm/yr between 1995 and 2018 CE. The indicative meaning at Balaoan, defined as the relationship between local water levels and the highest level of growth of a coral microatoll before its most recent diedown, is estimated at 31.5 +/- 10.0 cm (2 sigma) above lowest astronomical tide
Yi shui er ju — Songjiang pingyuan diqu huan Yueliangpao quyuxing xitong diaocha zhuyao shouhuo 依水而居—松江平原地区环月亮泡区域性系统调查主要收获
No full textInternational audienceBetween 2012 and 2016, a 280km² survey was carried out around the Yueliang and the Xinhuang Lakes in Da’an and Zhenlai Districts, in the northwestern part of Jilin Province, by a team lead by researchers from the Research Centre on Chinese Frontier Archaeology at Jilin University. This is the first systematic regional survey ever carried out in Jilin Province. It sheds light on the settlement patterns of each occupation periods between 10 000BC and the beginning of the 20th c. AD. After presenting the diachronical changes of settlement spatial structure for each period and related data about subsistence, this research engages a discussion by comparing the present results with the surveys previously carried out in the Liaoxi and other regions to better understand the diversity of settlement patterns and economies in Northeast China on the longue durée
Constraints on sea-level rise during meltwater pulse 1B from the Great Barrier Reef
No full textInternational audienceThe timing, rate, and magnitude of rapid sea-level rise during Meltwater Pulse 1B (MWP-1B, ~11.45–11.1 ka) remain controversial. Robust constraints on past MWPs are crucial to future predictions of global ice sheet instability. Using 154 new and existing U/Th and calibrated 14C-AMS dates from coral, algae, and microbialites recovered during Integrated Ocean Drilling Program Expedition 325, this study reconstructs reef development and relative sea-level (RSL) rise on the Great Barrier Reef (GBR). We identify 107 in situ RSL index points while refining estimates of vertical accretion and paleowater depth. Results show RSL rise during MWP-1B did not exceed 10.2–7.7 m or rates of 30–23 mm/yr, and was likely less. The GBR did not drown, indicating resilience to MWP-1B. These findings are more consistent with Tahiti and other Pacific records and do not support the Barbados record of MWP-1B as an abrupt step in global sea level, with a magnitude > 11 m
Beyond sparse denoising in frames: minimax estimation with a scattering transform
No full textA considerable amount of research in harmonic analysis has been devoted to non-linear estimators of signals contaminated by additive Gaussian noise. They are implemented by thresholding coefficients in a frame, which provide a sparse signal representation, or by minimising their norm. However, sparse estimators in frames are not sufficiently rich to adapt to complex signal regularities. For cartoon images whose edges are piecewise curves, wavelet, curvelet and Xlet frames are suboptimal if the Lipschitz exponent is an unknown parameter. Deep convolutional neural networks have recently obtained much better numerical results, which reach the minimax asymptotic bounds for all . Wavelet scattering coefficients have been introduced as simplified convolutional neural network models. They are computed by transforming the modulus of wavelet coefficients with a second wavelet transform. We introduce a denoising estimator by jointly minimising and maximising the norms of different subsets of scattering coefficients. We prove that these norms capture different types of geometric image regularity. Numerical experiments show that this denoising estimator reaches the minimax asymptotic bound for cartoon images for all Lipschitz exponents . We state this numerical result as a mathematical conjecture. It provides a different harmonic analysis approach to suppress noise from signals, and to specify the geometric regularity of functions. It also opens a mathematical bridge between harmonic analysis and denoising estimators with deep convolutional network
Very-wide-orbit planets from dynamical instabilities during the stellar birth cluster phase
No full textInternational audienceOur understanding of the process of terrestrial planet formation has grown markedly over the past 20 years, yet key questions remain. This review begins by first addressing the critical, earliest stage of dust coagulation and concentration. While classic studies revealed how objects that grow to meter sizes are rapidly removed from protoplanetary disks via orbital decay (seemingly precluding growth to larger sizes), this chapter addresses how this is resolved in contemporary, streaming instability models that favor rapid planetesimal formation via gravitational collapse of solids in over-dense regions. Once formed, planetesimals grow into Mars-Earth-sized planetary embryos by a combination of pebble- and planetesimal accretion within the lifetime of the nebular disk. After the disk dissipates, these embryos typically experience a series of late giant impacts en route to attaining their final architectures. This review also highlights three different inner Solar System formation models that can match a number of empirical constraints, and also reviews ways that one or more might be ruled out in favor of another in the near future. These include (1) the Grand Tack, (2) the Early Instability and (3) Planet Formation from Rings. Additionally, this chapter discusses formation models for the closest known analogs to our own terrestrial planets: super-Earths and terrestrial exoplanets in systems also hosting gas giants. Finally, this review lays out a chain of events that may explain why the Solar System looks different than more than 99% of exoplanet systems