Cyclic Behaviour of Soils and Liquefaction Phenomena

International audience; Coastal or offshore structures such as pipelines installed on the seabed are submitted to the hydrodynamic action of the waves either by a direct application of cyclic wave loads or through the cyclic movement of risers or flow lines transmitted by floating structures. In fine sandy or silty soils the cyclic loads can induce a liquefaction of the surrounding bed which can play an important part in the processes of erosion, trenching or self-burial of the pipes. A large 1 g physical model was built to study the fluid-soil-structure interaction with special emphasis on the conditions of occurrence of liquefaction around a pipe instrumented with pore pressure sensors. The experiments indicate a build up in pore pressure at the pipe-soil interface and a lateral visualisation showed a liquefaction of a soil band in the vicinity of the pipe. The penetration of the structure can be related to the phenomenon of liquefaction. Document type: Boo

A VLT/VIMOS view of two PlanckPlanck multiple-cluster systems: structure and galaxy properties

We analysed spectroscopic data obtained with VLT-VIMOS for two multiple-cluster systems, PLCKG$214.6+36.9$ and PLCKG$334.8-38.0$, discovered via their thermal Sunyaev-Zel'dovich signal by $Planck$. Combining the Optical spectroscopy, for the redshift determination, and photometric data from galaxy surveys (SDSS, WISE, DESI), we were able to study the structure of the two multiple-cluster systems, to determine their nature and the properties of their member galaxies. We found that the two systems are populated mainly with passive galaxies and that PLCKG$214.6+36.9$ consists of a pair of clusters at redshift $z = 0.445$ and a background isolated cluster at $z = 0.498$, whereas the system PLCKG$334.8-38.0$ is a chance association of three independent clusters at redshifts $z = 0.367$, $z =0.292$, and $z = 0.33$. We also find evidence for remaining star formation activity in the highest-redshift cluster of PLCKG$214.6+36.9$, at $z = 0.498$.Comment: 12 pages, 9 Figures, 5 Tables. Submitted to A&A, comments are welcom

A 3D-CTM with detailed online PSC-microphysics: analysis of the Antarctic winter 2003 by comparison with satellite observations

International audienceWe present the first detailed microphysical simulations which are performed online within the framework of a global 3-D chemical transport model (CTM) with full chemistry. The model describes the formation and evolution of four types of polar stratospheric cloud (PSC) particles. Aerosol freezing and other relevant microphysical processes are treated in a full explicit way. Each particle type is described by a binned size distribution for the number density and chemical composition. This set-up allows for an accurate treatment of sedimentation and for detailed calculation of surface area densities and optical properties. Simulations are presented for the Antarctic winter of 2003 and comparisons are made to a diverse set of satellite observations (optical and chemical measurements of POAM III and MIPAS) to illustrate the capabilities of the model. This study shows that a combined resolution approach where microphysical processes are simulated in coarse-grained conditions gives good results for PSC formation and its large-scale effect on the chemical environment through processes such as denitrification, dehydration and ozone loss. It is also shown that the influence of microphysical parameters can be measured directly from these processes

4D-Var Assimilation of MIPAS chemical observations: ozone and nitrogen dioxide analyses

International audienceThis paper discusses the global analyses of stratospheric ozone (O3) and nitrogen dioxide (NO2) obtained by the Belgian Assimilation System for Chemical Observations from Envisat (BASCOE). Based on a chemistry transport model (CTM) and the 4-dimensional variational (4D-Var) method, BASCOE has assimilated chemical observations of O3, NO2, HNO3, N2O, CH4 and H2O, made between July 2002 and March 2004 by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard the European Space Agency (ESA) Environment Satellite (ENVISAT). This corresponds to the entire period during which MIPAS was operating at its nominal resolution. Our analyses are evaluated against assimilated MIPAS data and independent HALOE (HALogen Occultation Experiment) and POAM-III (Polar Ozone and Aerosol Measurement) satellite data. A good agreement is generally found between the analyses and these datasets, in both cases within the estimated error bars of the observations. The benefit of data assimilation is also evaluated using a BASCOE free model run. For O3, the gain from the assimilation is significant during ozone hole conditions, and in the lower stratosphere. Elsewhere, the free model run is within the MIPAS uncertainties and the assimilation does not provide significant improvement. For NO2, the gain from the assimilation is realized through most of the stratosphere. Using the BASCOE analyses, we estimate the differences between MIPAS data and independent data from HALOE and POAM-III, and find results close to those obtained by classical validation methods involving only direct measurement-to-measurement comparisons. Our results extend and reinforce previous MIPAS data validation efforts by taking account of a much larger variety of atmospheric states and measurement conditions. This study discusses possible further developments of the BASCOE data assimilation system; these concern the horizontal resolution, a better filtering of NO2 observations, and the photolysis calculation near the lid of the model. The ozone analyses are publicly available via the PROMOTE project http://www.gse-promote.org)

Preliminary reports on the 2016-2017 excavation of the Neolithic ossuary and terrace

This article reports on the first three systematic excavation seasons at the Neolithic ossuary of Grotte de La Faucille, Belgium. The site was dated on human bone to 4266 ± 40 14C BP (3011-2702 cal BC; 2 sigma), corresponding to the transition from the late to the final Neolithic. The area excavated to date is clearly reworked and the individuals are distributed across the site. Further excavation will focus on the inferior levels at the entrance and inside the cave. This report presents the preliminary analysis of the anthropological and archaeological evidence recorded to date. Five archaeological artefacts were discovered made on bone, tooth and flint. The site has produced skeletal and dental remains of at least 12 humans (MNI 6 juveniles and 6 adults) as well as a number of bone and lithic artefacts. The skeletal remains are fragmentary and some elements, such as the cranium, are highly underrepresented given the number of individuals. The potential to find the remainder of at least 12 individuals is promising and continued excavation may result in one of the largest recent excavation of a multiple Neolithic burial site of the 21st century. The results presented here and ongoing analysis have the potential to significantly expand our understanding of the mortuary behaviours, or variation in behaviours, of the Belgian Neolithic and contribute further to the lively debate on the spread of the Neolithic

Temporal variation in cave bear (Ursus spelaeus) dentition: The stratigraphic sequence of Scladina Cave, Belgium

© 2018 Elsevier Ltd The supposed herbivorous cave bear (Ursus spelaeus) occupied Europe throughout the Quaternary. Being subject to large spatial variation has led to the intensive study on its geographical polymorphism, generating debates on sub-speciation. However, temporal morphological information on the species is somewhat lacking. Here, we apply geometric morphometrics (GMM) technique to investigate temporal morphological variation in molar size and shape of Ursus spelaeus from different chronostratigraphic sediment units in a geographically confined site (Scladina Cave, Belgium), covering approximately 100,000 years. Our findings show significant morphological variation between groups analysed in both size and shape. M2 shows a chronological size increase with PCA plots visually expressing differences in all groups, relating to a buccolingual expansion and an increase of the talon masticatory platform through time. Reduction in the M1 is also shown, possibly to maintain biomechanical performance of dentition for effective mastication, more so in groups relating to the latter stages of the Quaternary. Findings suggest a rapid response to climatic factors constraining consumable food sources, with GMM offering a promising analytical approach in understanding the palaeobiology, palaeoecology and morphological variation in extinct and extant fossil mammals

DigiArt: towards a virtualization of Cultural Heritage

DigiArt is a Europe-wide project aimed at providing a new, cost efficient solution to the capture, processing and display of cultural artefacts. The project will change the ways in which the public interact with cultural objects and spaces in a dramatic way. This project is unique in its collaborative approach: cultural heritage professionals working directly with electrical, mechanical, optical and software engineers to develop a solution to current issues faced by the museum sector. The innovations created by the engineers are driven by the demand of the cultural heritage sector. The diversity of the objects and spaces of the three test museums are challenging the engineers to provide a tool useful for a broad variety of indoor and outdoor museums in the future. This goes from using Unmanned Aerial Vehicle (UAVs or drones) to fly and record large sites, to using scanners to record fine jewellery. As a case study, we present here the use-case of Scladina Cave. At the end of the project, the Scladina Cave Archaeological Centre will offer two different visitor experiences. The first uses virtual reality, which will be available anytime, anywhere, to anyone with an internet connected device. The second will use augmented reality technologies within the cave site. The augmented reality visit of the cave will enhance the tour of Scladina by offering visits that would not be possible where it not for the augmented reality, where 3D objects and animations will contribute to offer a new 3D-immersive experience

Nuclear DNA from two early Neandertals reveals 80,000 years of genetic continuity in Europe

Little is known about the population history of Neandertals over the hundreds of thousands of years of their existence. We retrieved nuclear genomic sequences from two Neandertals, one from Hohlenstein-Stadel Cave in Germany and the other from Scladina Cave in Belgium, who lived around 120,000 years ago. Despite the deeply divergent mitochondrial lineage present in the former individual, both Neandertals are genetically closer to later Neandertals from Europe than to a roughly contemporaneous individual from Siberia. That the Hohlenstein-Stadel and Scladina individuals lived around the time of their most recent common ancestor with later Neandertals suggests that all later Neandertals trace at least part of their ancestry back to these early European Neandertals

Methodological Guidelines for Engineering Self-organization and Emergence

The ASCENS project deals with the design and development of complex self-adaptive systems, where self-organization is one of the possible means by which to achieve self-adaptation. However, to support the development of self-organising systems, one has to extensively re-situate their engineering from a software architectures and requirements point of view. In particular, in this chapter, we highlight the importance of the decomposition in components to go from the problem to the engineered solution. This leads us to explain and rationalise the following architectural strategy: designing by following the problem organisation. We discuss architectural advantages for development and documentation, and its coherence with existing methodological approaches to self-organisation, and we illustrate the approach with an example on the area of swarm robotics