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We construct a two discrete parameter family of compact minimal surfaces embedded in the Berger sphere which may be considered as the analogue of the helicoidal Karcher-Scherk surfaces. [ABSTRACT FROM AUTHOR]

We study the mechanical response, and tearing features of crêpe paper, a two-dimensional, very anisotropic material, with one direction much less stiff than the other one. Depending on how the soft direction has been pre-stretched or not, the apparent Young modulus of the material can be varied over a broad range, while its fracture energy remains unaltered. The classical tearing concertina problem shows that a macroscopic measurement (the shape of the teared region) provides a direct access to the fracture properties of the material (effective Young's modulus, and fracture energy). The overall discussion is conducted in the frame of Griffith's theory of fracture. [ABSTRACT FROM AUTHOR]

We indicate some important simplifications and extensions of the analysis recently given by J. Benameur to derive blow-up estimates for strong solutions to 3D incompressible Navier–Stokes equations in homogeneous Sobolev spaces H ˙ s ( R 3 ) , s > 1 / 2 , in case of finite-time existence. [ABSTRACT FROM AUTHOR]

This appendix gives a lower bound of the Billingsley-Hausdorff dimension of a level set related to Birkhoff average in the "non-compact" symbolic space NN, defined by Gibbs measure. [ABSTRACT FROM AUTHOR]

This paper presents the cornerstones of the conceptual distinctions necessary to map out a separate category of workers, namely "economically dependent self-employed workers" (who fall between dependent subordinated employees and independent self-employed entrepreneurs) from the perspective of the EU law and the laws of selected Member States. The author considers how the economic dependency of self-employed workers should be defined, which method(s) of protection should be applied to these workers, and what scope of protection they should enjoy. The observations in this paper serve as a basis for de lege ferenda recommendations for the Polish legislator. At present, there is no separate category of "economically dependent self-employed workers" in Polish law. [ABSTRACT FROM AUTHOR]

The understanding of the taxonomy, diversity, and evolutionary patterns of caviids in northwestern Argentina is still in the process of development. This paper presents new insights into the systematic and evolution of Orthomyctera andina (Rovereto, 1914), one of the most abundant species within Caviidae Fischer de Waldheim, 1817, in the fossil record of this region. A comprehensive anatomical description and taxonomic review of Orthomyctera andina in a phylogenetic context is provided. Moreover, it includes a redescription of the type specimen of Orthomyctera rigens (Ameghino, 1888). The taxonomical results confirm that O. andina belongs to a different genus: Orocavia (Kraglievich, 1932). The phylogenetic analysis further confirms the placement of both species within Caviinae Fischer de Waldheim, 1817. Orthomyctera andina is the sister taxon of the clade that includes Microcavia Gervais & Ameghino, 1880, Dolicavia Ameghino, 1916, Neocavia Kraglievich, 1932, and Orthomyctera Ameghino, 1889. It is supported by a combination of plesiomorphic characters (e.g. furrow opposite to hypoflexus/id in molariforms) shared with basal taxa and Dolichotinae Pocock, 1922 and derived characters (such as a terreced palate, external auditory meatus below the occlusal surface, length of p4-m1 shorter than length of m2-m3) shared with Caviinae. This study aims to elucidate the taxonomic status of these poorly known rodents and their relationships within Caviidae. Additionally, it incorporates a biogeographic analysis of caviomorph communities from the late Neogene in Argentina. [ABSTRACT FROM AUTHOR]

Šandalja II has been a reference site for numerous decades for the definition and study of the Eastern Adriatic Upper Palaeolithic and corresponding techno-complexes. This is due both to its extensive material record, and the purported presence of some otherwise elusive techno-complexes in the area, such as the Aurignacian and the Early Epigravettian. In this paper, we present two new series of C14-AMS dates (from layers H, E, C/d and A/d) to assess the validity of its archaeological sequence, together with previously obtained radiocarbon dates, both AMS and conventional. The results show, unambiguously, the lack of reliability of the stratigraphy defined for the site during the excavation. A simple chronometric deconstruction reveals, at the very least, that the assemblages from Šandalja II can no longer be considered and used as an example of the diachronic evolution within the Aurignacian and Epigravettian of the Eastern Adriatic, thus calling for a further reevaluation of features defined for the Adriatic Upper Palaeolithic on the basis on the assemblages from Šandalja II. Hence Šandalja II joins an increasing list of so-called reference sites which must not be considered as "referential" anymore. [ABSTRACT FROM AUTHOR]

Since its appearance in the first century BC, the water wheel has developed with increasing pre-industrial activities, and has been at the origin of the industrial revolution for metallurgy, textile mills, and paper mills. Since the nineteenth century, the water wheel has become highly efficient. The reaction turbine appeared by 1825, and continued to undergo technological development. The impulsion turbine appeared for high chutes, by 1880. Other turbines for low-head chutes were further designed. Turbine development was associated, after 1890, with the use of hydropower to generate electricity, both for industrial activities, and for the benefits of cities. A model “one city + one plant” was followed in the twentieth century by more complex and efficient schemes when electrical interconnection developed, together with pumped plants for energy storage. [ABSTRACT FROM AUTHOR]

Optical interferometry has always been seen as a promising but difficult technique for astronomy. Until the year 2018, it was excrucially limited in sensitivity to magnitudes below 10. However, thanks to the advent of the GRAVITY instrument, fringe tracking and dual field interferometry made it possible to observe very faint target. This paper presents the different techniques used by optical interferometry to perform astrometry. It shows why dual field interferometry has become the key technique for faint companions. Taking the example of the HD95086 b exoplanet, we show how dual field interferomtry can detect an exoplanet as faint as magnitude 19.5, and how its astrometry was extracted. Use this example this paper explains how and why an astrometric accuracy of 10 µas is possible, and describes the remaining biases that can hinder this measurement. Last, we conclude by presenting the orbital trajectory of 10 exoplanets in 4 systems, and conclude with the short and longer term perspectives of the technique. [ABSTRACT FROM AUTHOR]

At a conference some years ago, one of the attendees came up to Ghislain de Marsily and asked, "Excuse me, but aren't you the de Marsily who developed the Pilot Point Method? It is an honor to meet you." His response highlights one of Ghislain's greatest qualities, his humility: "Yes I am, thank you, you are very kind, but that was a very long time ago." Since Ghislain de Marsily first developed the Pilot Point Method (PPM) in 1978, its development and use has grown significantly in applied decision-supportmodeling settings including hydrogeology, aswell as in other industries, e.g., petroleum reservoir engineering. A technique that was once confined to academic realms, the PPM is now widely accepted as one of the industry pillars of inversion and uncertainty quantification for predictive groundwater modeling. Herein, we provide an update to de Marsily's paper entitled "Four Decades of Inverse Problems in Hydrogeology" [DeMarsily et al., 2000], but with a particular focus on the incredible adoption and advancement of deMarsily's PPM and related inverse techniques over the last twenty years in the field of predictive groundwater modeling. Much has been written about the vast array of inverse techniques developed by researchers and practitioners since the 1960s. de Marsily's PPM, like many methods developed in the late 70s and early 80s, structured its approach to parameterization to overcomemany of the challenges of applying inverse methods to real world problems, namely, limited head and transmissivity data relative to the number of unknowns to be estimated, measurement errors, inferred covariance structures of the state variables, and limited computational resources. While inversion research continues, only deMarsily's PPM has achieved wide-spread adoption within the groundwater modeling community. The reasons for the popularity of the PPM aremany but none more important than its adoption by John Doherty's PEST inversion software in the early 2000s [Doherty, 2003]. This paper will review the advancements and adaptations of the PPM over the last two decades which have led to its ubiquity. Significant reductions in inversion time are transforming the way in which practitioners are deploying thePPMto improve their understanding of hydrogeologic systems, and, ultimately, to provide decision support for water resource management. The paper ends with newly developed applications of the PPM, given modern machine learning capabilities, and some foreshadowing as to where the PPM might evolve. [ABSTRACT FROM AUTHOR]

The present work is a continuation of a paper presented by the two first authors in the proceedings of the "Computational Science for the 21st century" conference held in Tours in 1997 honouring the 60th birthday of Roland Glowinski. It is devoted to the solution of 1D convection-diffusion equations in dominant convection regime situations. In that paper, an "a posteriori" VMS filtering technique was introduced. We present an extension of this technique to nonlinear convection-diffusion equations (a traffic model), providing an efficient method for the resolution of shocks from just the Galerkin solution at targeted times. We also present a residual-based "a posteriori" VMS filtering, that provides quite accurate stable solutions, can be extended to multi-dimensional problems, and can be applied locally. We finally present some numerical tests exhibiting the high accuracy of the obtained solutions. [ABSTRACT FROM AUTHOR]

In this paper, we study the Dirichlet problem for a semilinear pseudo-parabolic equation. By using the energy estimates and ordinary differential inequalities, we studied the upper and lower bounds of blowup time of the solutions. The results of this paper extend and complete the results on this model. [ABSTRACT FROM AUTHOR]

The subsistence strategies of early farming communities have been highlighted since the beginning of the Neolithic, thanks to numerous studies on lipid residues from ceramic vessels conducted in various parts of continental Europe. However, after the Early Neolithic, evidence of subsistence strategies along the northern Atlantic coast are still lacking, especially for island contexts. This paper presents the results of lipid residue analysis of 129 potsherds from Beg ar Loued (Molène, France), an island site dating primarily to the Early Bronze Age (c. 2700-2600 to 1800 BCE). Aiming to understand the use of vessels, vessel treatment and culinary practices on the settlement, analyses of visible charred residues, sherds and ceramic surfaces/coating layers were carried out using chromatographic (n = 174) and isotopic techniques (n = 24) after lipid extraction by solvent (n = 174) or acid methanolysis (n = 31). The results demonstrate the extensive use of terrestrial products (ruminant carcass and dairy) in pottery, including occasional plant products (with possible mixtures of different waxes), while the detection of aquatic products is limited. Thus, combined with evidence from faunal remains at the site, the results indicate that terrestrial resources like ruminant meat and dairy products were preferentially processed in vessels, and aquatic products mostly without the use of ceramics. These findings demonstrate the significance of lipid residue analysis for studying the role of pottery in food production and consumption at sites along the Atlantic coast. [ABSTRACT FROM AUTHOR]

Based on a review of literature and a few case studies, this paper summarizes the state of the art on the dating of folds and thrusts, then presents and discusses how recent advances in K-Ar illite and U-Pb calcite geochronology applied to brittle structures in fold-and-thrust belts have helped better constrain the timing, sequence, duration and rates of deformation. [ABSTRACT FROM AUTHOR]

The paper provides an overview of the Chilotherium Ringström, 1924 fossils from Romania, which are recorded so far in three different Upper Miocene localities of the Eastern Carpathians Foreland: mammal localities of Reghiu, Bacău and Pogana. The fossils include a partial skull, several maxillary and mandible fragments and isolated teeth. They have been partially illustrated, but never described excepting the isolated teeth of Pogana. The previous assignments were confusing, ranging from Chilotherium schlosseri (Weber, 1905) and C. cf. sarmaticum for Reghiu specimens to an indeterminate species close to C. sarmaticum Korotkevich, 1958, C. kiliasi (Geraads & Koufos, 1990), and C. kowalevskii (Pavlow, 1913) for Pogana teeth. Based on descriptions and comparisons with other Chilotherium remains, all specimens from Romania can be referred to C. schlosseri. Chilotherium schlosseri is the most widespread species of the genus, ranging from Eastern Europe to Central Asia. The presence of this genus in Romania, and more globally in Eastern Europe, attests to a transition area between the more closed and wooded environments of Western Europe (where Chilotherium is absent) to the more open ones in Asia. [ABSTRACT FROM AUTHOR]

A new marine volcano is erupting offshore Mayotte since May 2018, generating numerous earthquakes. The population felt many of them and the stronger shaking of the ongoing sequence caused slight damage to buildings. Historical records also confirm that damaging earthquakes had occurred in the past in this region. Seismic damage scenarios are a key tool for supporting the decision-making process, the preparedness, and for designing appropriate emergency responses. This paper provides the outcomes of a work consisting in improving the seismic risk assessment as a part of disaster risk governance and exposes the scientific background of this workflow. It illustrates its use with two earthquakes. Related post-seismic surveys provide observations that are useful to check the validity of the reference dataset. The paper also discusses the main characteristics of the rapid loss assessment tool that has been developed to provide operational information for crisis management. [ABSTRACT FROM AUTHOR]

Today, adaptive optics (AO) is installed on all very large astronomical telescopes. It allows to overcome the limitation in angular resolution imposed on large ground-based telescopes by the atmospheric turbulence perturbations. This review paper presents the state of the art of the field for astronomical applications. It gives the principles of AO and describes itsmain components which are the deformable mirrors, the wavefront sensors and the control algorithms. The paper also presents the main recent achievements and ongoing projects. First, for the direct imaging of extra-solar planets by extreme AO and coronography, taking as example the SPHERE instrument. Then to solve the problem of the very limited sky coverage by using laser guide star and to extend the AO correction beyond the isoplanatic patch. Thus, the various laser-assisted tomographic AO concepts are presented with examples of each realization as for the laser tomography AO, the multi-conjugate AO and the multi-object AO. Finally, the challenges of the new generation of giant telescopes are discussed at the end of the paperwith a particular focus on the European Extremely Large Telescope (ELT) project. [ABSTRACT FROM AUTHOR]

In 1985 Crapo introduced in [3] a new mathematical object that he called geometry of circuits. Four years later, in 1989, Manin and Schechtman defined in [13] the same object and called it discriminantal arrangement, the name by which it is known now a days. Those discriminantal arrangements B(n,k,A 0 ) are builded from an arrangement A 0 of n hyperplanes in general position in a k-dimensional space and their combinatorics depends on the arrangement A 0 . On this basis, in 1997 Bayer and Brandt (see [2]) distinguished two different type of arrangements A 0 calling very generic the ones for which the intersection lattice of B(n,k,A 0 ) has maximum cardinality and non-very generic the others. Results on the combinatorics of B(n,k,A 0 ) in the very generic case already appear in Crapo [3] and in 1997 in Athanasiadis [1] while the first known result on non-very generic case is due to Libgober and the first author in 2018. In their paper [12] they provided a necessary and sufficient condition on A 0 for which the cardinality of rank 2 intersections in B(n,k,A 0 ) is not maximal anymore. In this paper we further develop their result providing a sufficient condition on A 0 for which the cardinality of rank r, r ≥ 2, intersections in B(n,k,A 0 ) decreases. [ABSTRACT FROM AUTHOR]

Anantharaman and Le Masson proved that any family of eigenbases of the adjacency operators of a family of graphs is quantum ergodic (a form of delocalization) assuming the graphs satisfy conditions of expansion and high girth. In this paper, we show that neither of these two conditions is sufficient by itself to necessitate quantum ergodicity. We also show that having conditions of expansion and a specific relaxation of the high girth constraint present in later papers on quantum ergodicity is not sufficient. We do so by proving new properties of the Cartesian product of two graphs where one is infinite. [ABSTRACT FROM AUTHOR]

The paper summarizes the main core of the last results that we obtained in [8, 4, 17] on the regularity of the value function for a Bolza problem of a one-dimensional, vectorial problem of the calculus of variations. We are concerned with a nonautonomous Lagrangian that is possibly highly discontinuous in the state and velocity variables, nonconvex in the velocity variable and non coercive. The main results are achieved under the assumption that the Lagrangian is convex on the one-dimensional lines of the velocity variable and satisfies a local Lipschitz continuity condition w.r.t. the time variable, known in the literature as Property (S), and strictly related to the validity of the Erdmann–Du-Bois Reymond equation. Under our assumptions, there exists a minimizing sequence of Lipschitz functions. A first consequence is that we can exclude the presence of the Lavrentiev phenomenon. Moreover, under a further mild growth assumption satisfied by the minimal length functional, fully described in the paper, the above sequence may be taken with the same Lipschitz rank, even when the initial datum and initial value vary on a compact set. The Lipschitz regularity of the value function follows. [ABSTRACT FROM AUTHOR]

Taphonomic analyses are of primary importance to understand the accumulation processes of fossil vertebrate bone assemblages. These approaches are fundamental in archaeological contexts in which the role of humans in the formation of an accumulation must be investigated in detail. However, taphonomic works have so far focused on temperate regions and mammals and few studies extensively deal with other vertebrates, especially the herpetofauna, and tropical areas. This results in an important gap in the scientific literature, which has a strong impact on the paleoecological and zooarchaeological research in the areas where squamates and amphibians are well-represented. In this paper, we present a detailed taphonomic study of a large herpetofaunal assemblage of nearly 11 000 bones collected in the Abri Cadet 3, on Marie Galante Island, and dated from the beginning of the Holocene to the Amerindian period. Obtained results don't support the role of humans in the constitution of the assemblage despite the occurrence of clear archaeological layers in the site. The most-likely culprit for the creation of the bone assemblage is a small nocturnal raptor (i.e., Athene cunicularia guadeloupensis (Ridgway, 1874) or Tyto insularis (Pelzeln, 1872)). We also conduct a comparison with the other available deposits from Marie Galante, highlighting the diversity of accumulation processes in the different nearby cave sites but also the lack of detailed taphonomic studies which would be needed to explain this diversity. [ABSTRACT FROM AUTHOR]

The SISFRANCE database aims to collect and interpret archives relating the historical seismicity in metropolitan France. The database presently contains some 12,500 documents that allow to define 108,832 macroseismic data points, for a total of 6427 events, of which 5743 can be qualified as real earthquakes. Although half of these events are and will probably remain poorly known, completing our knowledge of historical earthquakes remains a fundamental element for the definition of seismic hazard and the understanding of seismicity in France and low to moderate seismicity regions in general. The first aim of this paper is to explain the state of the art of the database and remind end users how the limits introduced by the necessary interpretation of archival data are translated into quality factors that should be carefully considered when using such data for seismotectonic and seismic hazard purposes. Originally built as part of the necessary datasets to define the seismic hazard for nuclear facilities, the SISFRANCE database is the result of 40 years of work within a consortium bringing together the French civil nuclear operator (EDF), the French geological survey (BRGM), and the French institute of nuclear safety (IRSN). SISFRANCE is also the heir to archival research carried out since the second half of the 19th century, thus constituting the richest collection of data related to historical seismicity in France. The second aim of this paper is to explain to end users the current state of archival research within the SISFRANCE consortium, present avenues for future research strategies, and list potential improvements of the database structure. Archival research within the SISFRANCE consortium, no longer carried out by a dedicated historian since 2018, is presently being pursued by engaging individual researchers or academics, focusing research on specific archives and regions, as well as by developing data-mining techniques to exploit the increasing wealth of accessible numerical archives. Given the new impetus of French governmental research agencies that encourage transdisciplinarity research, SISFRANCE is also pursuing the idea of further engaging the academic community of historians and seismologists, presently greatly underrepresented in the field of historical seismicity in spite of the importance of this data, fundamental for any seismotectonic and seismic hazard study in France. [ABSTRACT FROM AUTHOR]

This paper presents a case study from the Hiem cave (Hoà Bình province, North Vietnam) showing how a multidisciplinary approach in archaeological research can develop knowledge on the everyday life of the hunter-gatherer Hoabinhian groups occupying the cave during the early Holocene (8500-8200 cal BC). The archaeological analysis presents the characteristic Hoabinhian artefacts and their usage, while archeozoological, malacological and archaeobotanical research throw light on the way of life, including plant and animal elements of a daily diet as well as the settlement seasonality of the cave. [ABSTRACT FROM AUTHOR]

The present paper deals with the ecomorphological characteristics of two sympatric species of ictitheres: Ictitherium viverrinum Roth & Wagner, 1854 and Hyaenictitherium wongii (Zdansky, 1924) from the Late Miocene of the Eastern Mediterranean. These two species represent different taxonomic groups with allegedly distinct ecological roles. The values of 11 ecomorphological proxies were calculated using cranial and dental elements, in order to make an extensive comparison between them (body mass, bite force, canines' and incisors' bending strength, endocranial volume, relative rostral width, dental mesowear, intercuspid notches and carnassial vs grinding surfaces). The proxies show similar results for both species, pointing out that they had a similar ecological niche in the Late Miocene ecosystems. Carnivorans are usually in the top of the food chain, so the existence of two ecologically similar species in the same spatiotemporal range results in interspecific competition. This explains the geographical distinction of the two species with several localities being dominated by only one of the two (e.g. Samos for Hyaenictitherium Kretzoi, 1938 and Pikermi for Ictitherium Wagner, 1848). The reason for the prevalence of each genus can be associated with their postcranial morphology, as Hyaenictitherium has been proposed to be better adapted to chase hunting, because of its longer limbs, while Ictitherium is characterized by shorter and stouter limbs. [ABSTRACT FROM AUTHOR]

MIS 3 environmental conditions in Africa north of the Equator and the Arabian Peninsula have long been controversial due to data scarcity and methodological caveats. In this paper we compare 245 continental hydrological records and 11 long and continuous continental and marine cores with results from the IPSL general circulation model to discuss hydrological changes between 59 and 29 ka in North Tropical Africa, North (Mediterranean) Africa and the Arabian Peninsula. Despite a generally glacial context, wet conditions widely expanded giving place to numerous lakes, rivers and wetlands. The major result of our study is to show that humid conditions appeared much earlier and were more prevalent in the Arabian Peninsula than in Africa, due to the conjunction of monsoon rains in summer and Mediterranean rains in winter. The mechanisms driving MIS 3 humidity in our study area involve global cooling factors such as greenhouse concentrations and ice volume, which have impacted available moisture, orbital forcing, which impacts monsoon circulation and amplitude and sensitivity to the state of the AtlanticMeridional Overturning Circulation (AMOC). [ABSTRACT FROM AUTHOR]

The lost Tethys Ocean was the favorite topic of Jean Dercourt's research. The Tethys project and his 1986 paper displaying detailed reconstructions in 9 plates from the Triassic to the Present was the beginning of a series of projects organized around large consortia associating scientists from the academic and industrial worlds. The most recent evolutions of these reconstructions show unprecedented images of the evolving geology, including tectonics and paleoenvironments, through time of this complex puzzle. Central to Tethyan tectonics, Apulia, or Adria, has been drawn with different geometries and dimensions from the first concepts by Emile Argand, Kenneth Hsü or John Dewey, to the recent reconstructions by Douwe van Hinsbergen or Paul Angrand. We review here the main reconstructions published since 1924 and the evolution of concepts and methods. We finally discuss the importance of this type of syntheses for understanding large-scale geodynamic processes. [ABSTRACT FROM AUTHOR]

Exoplanetary science is a very active field of astronomy nowadays, with questions still opened such as how planetary systems form and evolve (occurrence, process), why such a diversity of exoplanets is observed (mass, radius, orbital parameters, temperature, composition), and what are the interactions between planets, circumstellar disk and their host star. Several complementary methods are used for the detection of exoplanets. Among these, imaging aims at the direct detection of the light reflected, scattered or emitted by exoplanets and circumstellar disks. This allows their spectral and polarimetric characterization. Such imaging remains challenging because of the large luminosity ratio (104-1010) and the small angular separation (fraction of an arcsecond) between the star and its environment. Over the past two decades, numerous techniques, including coronagraphy, have been developed to make exoplanet imaging a reality. This paper gives a broad overview of the subsystems that make up a coronagraphic instrument for imaging exoplanetary systems. It is especially intended for non-specialists or newcomers in the field. We explain the principle of coronagraphy and propose a formalism to understand their behavior. We discuss the impact of wavefront aberrations on the performance of coronagraphs and how they induce stellar speckles in the scientific image. Finally, we present instrumental and signal processing techniques used for on-sky minimization or a posteriori calibration of these speckles in order to improve the performance of coronagraphs. [ABSTRACT FROM AUTHOR]

Understanding how giant and terrestrial planets form and evolve, what is their internal structure and that of their atmosphere, represents one of the major challenges of modern astronomy, which is directly connected to the ultimate search for life at the horizon 2030--2050. However, several astrophysical (understanding of the formation and physics of giant and terrestrial exoplanets), biological (identification of the best biomarkers) and technological (technical innovations for the new generations of telescopes and instruments) obstacles must be overcome. From the astrophysical point of view, it is indeed crucial to understand the mechanisms of formation and evolution of giant planets, including planet and disk interactions, which will completely sculpt the planetary architectures and thus dominate the formation of terrestrial planets, especially in regions around the host star capable of supporting life. It is also important to develop dedicated instrumentation and techniques to study in their totality the population of giant and terrestrial planets, but also to reveal in the near future the first biological markers of life in the atmospheres of terrestrial planets. In that perspective, direct imaging from ground-based observatories or in space is playing a central role in concert with other observing techniques. In this paper, I will briefly review the genesis of this observing technique, the main instrumental innovation and challenges, stellar targets and surveys, to then present the main results obtained so far about the physics and the mechanisms of formation and evolution of young giant planets and planetary system architectures. I will then present the exciting perspectives offered by the upcoming generation of planet imagers about to come online, particularly on the future extremely large telescopes. On the timescale of a human Life, we may well be witnessing the first discovery of an exoplanet and the first detection of indices of life in the atmosphere of a nearby exo-Earth! [ABSTRACT FROM AUTHOR]

The spectral characterization of exoplanetary atmospheres is a relatively new subject. Until recently, space and ground-based observatories allowed only a few planets to be observed with spectroscopic instruments. The arrival of JWST data and the development of new instruments on Earthwill drastically modify the situation, giving access to deeper modelling contraints and to a better understanding on planet formation and evolution. This paper is devoted to describe the turning point experienced by the astronomy of exoplanets that will continue in particular with the launch of the ESA/Ariel mission at the end of the decade [ABSTRACT FROM AUTHOR]

The technological developments initiated in the early 21st century have led to the implementation of "planet finders" instruments on 8-m class telescopes which are in operation since 2014-2015. Such facilities are at the inception of significant progresses in the study of exoplanetary systems by enabling high contrast imaging of the environment of young nearby stars. One of the most productive science in this field is certainly the observations at high angular resolution of circumstellar disks, from the very young gas-rich protoplanetary disks all the way to more elusive dust-rich debris disks. In this paper, we summarize the main results obtained for these two categories of objects focusing on their morphological characteristics, as well as on the measurement of optical properties of the small dust particles to which the near IR spectral range is sensitive to. We mostly provide examples based on observations performed with the SPHERE instrument at the VLT. [ABSTRACT FROM AUTHOR]

The objective of the paper is to better understand and quantify the flow structure in fractured rocks from flow logs, and to propose relevant indicators for validating, calibrating or even rejecting hydrogeological models. We first studied what the inflow distribution tells us about the permeability structure from a series of analyses: distribution of transmissivities as a function of depth, proportion of flowing sections as a function of section scale, and scaling of the arithmetically-averaged and geometrically-averaged permeability. We then define three indicators that describe few fundamental characteristics of the flow/permeability, whatever the scale: a percolation scale ls, the way permeability increases with scale above ls, and the variability of permeability. A 4th indicator on the representative elemental volume could in principle be defined but the data show that this volume/scale is beyond the 300 m investigated. We tested a series of numerical models built in three steps: the geo-DFN based on the observed fracture network, the open-DFN which is the part of the geo-DFN where fractures are open, and a transmissivity model applying on each fracture of the open-DFN (Discrete Fracture Network). The analysis of the models showed that the percolation scale is controlled by the open-DFN structure and that the percolation scale can be predicted from a scale analysis of the percolation parameter (basically, the third moment of the fracture size distribution that provides a measure of the network connectivity). The way permeability increases with scale above the percolation threshold is controlled by the transmissivity model and in particular by the dependence of the fracture transmissivity on either the orientation of the fractures via a stresscontrolled transmissivity or their size or both. The comparison with data on the first two indicators shows that a model that matches the characteristics of the geo-DFN with an open fraction of 15% as measured adequately fits the data provided that the large fractures remain open and that the fracture transmissivity model is well selected. Most of the other models show unacceptable differences with data but other models ormodel combinations has still to be explored beforerejecting them. The third indicator on model variability is still problematic since the natural data show a higher variability than the models but the open fraction is also much more variable in the data than in the models. [ABSTRACT FROM AUTHOR]

Identifying factors and quantifying the processes, influencing the extent of reservoir rocks and the distribution of their heterogeneities are fundamental prerequisites to improve the characterization of reservoir connectivity and its dynamic functioning. In this paper, we propose a multiscale approach based on combined geological-geophysical investigations, geostatistics, and 3D geological modeling to build a structural model of faulted-reservoir systems, at regional and local scales within the Jeffara basin, southeast Tunisia. The regional modeling procedure is calibrated by outcrops, a Digital Elevation Model (DEM), boreholes, and well data logs. The geological processing, itself, is used as a tool to extend the database from a variety of documents such as geological maps, geological cross-sections, outcrop descriptions, and especially the wealthy geological knowledge. The original and extended data are then coded and stored in a common georeferenced database. This provides a detailed input for the geostatistical modeling procedures that enabled to precisely capture the varying extent and shape of the hydrogeological units at regional scale. Geophysical data, available along the Jeffara plain, were added as a complement to the Jeffara geodatabase and used to establish the fault network and to build a local architectural model of the coastal aquifer system, based on time-to-depth conversion using kriging with external drift. The results have allowed (i) a major update of the geological configuration of the Jeffara basin, (ii) more precision on the geometries and extent of the stratigraphic sequences and (iii) an accurate prediction of the main characteristics of water reservoirs, i.e. their occurrence, thickness, facies and dynamic properties variation at the basin and reservoir scale. Such multiscale modeling provided effective tools for better understanding the hydrostratigraphic setting, the hydrodynamic functioning of neighboring aquifers, and to assist water resources management. [ABSTRACT FROM AUTHOR]

This paper is intended to be a reminder of a series of scientific works whose origin is largely attributable to G. deMarsily, without attempting tomake an exhaustive overview of submarine springs and coastal karst aquifers. The main results show that coastal karst aquifers with their submarine outlets and the possibility of natural seawater intrusion are particularly fragile and must be studied and managed with appropriate tools. For the coming decades, the evolution of the climate as results from the IPCC scenarios leads us to question the effects of the increase of sea level on this coastal resource, and the effects of frequent and severe droughts, added to an increase in withdrawals from aquifers caused by the coastalisation of the population. [ABSTRACT FROM AUTHOR]

Noting that humans are affecting the Earth's envelopes, with geosciences becoming inseparable from social sciences and humanities, and acknowledging the increasing use of the word Anthropocene, the authors of this paper explore the possibility of a scientific paradigm shift. (1) Since the 17th century, modern science has developed in a context of naturalist worlding that favors its hegemony over other modes of existence and its paradigm of a quest to define the laws of nature. (2) Various manifestations attest to the emergence of a paradigm of knowledge diversity and the unravelling of the naturalist worlding. (3) The current boom in participatory science is a sign of this paradigm shift: through the fundamental changes to the Earth System that refer to it, the Anthropocene forces science to move towards action and interact with a society involved in adapting to changes and concerned with the threats to its territory's habitability. [ABSTRACT FROM AUTHOR]

This paper revisits the controversy on the validation of hydrogeological models, 30 years after it broke out with the publications by Konikow and Bredehoeft [1992a] and deMarsily et al. [1992]. In that debate, Konikow and Bredehoeft [1992a] argued that the word "valid" was misleading to the public and should not be used with respect to models. de Marsily et al. [1992] answered that while the bases of hydrogeological models (conservation of mass and Darcy's law) were uncontestable and unconditionally valid, specific validation exercises were dearly needed to evaluate the parameters and the geometry of these models (confronting the models with data they had not seen during the calibration phase). By updating and extending the literature review, we reanalyze this debate and the arguments presented and conclude by proposing an extension of de Marsily's position, which underlines the necessity to look at validation from two distinct viewpoints, i.e. the point of view of themodel's explanatory power (theoretical content) and the point of view of its predictive power. The explanatory and predictive dimensions of model validation are to be considered separately. [ABSTRACT FROM AUTHOR]

Groundwater is an essential water resource for domestic use, agriculture and other socioeconomic activities, as well as ecological services around the world. Participative approach to water resources management is essential, and requires all stakeholders to have sufficient knowledge and understanding of processes taking place, from rainfall to recharge, drainage and discharge [De Marsily and Besbes, 2017]. Understanding unseen processes require abstraction and imagination. In many cases, detailed 3D conceptual models may help non-specialists to understand underground environments and thereby address questions related to the management of groundwater resources [Jeannin et al., 2013, Malard, 2018]. In order to increase the understanding of dynamic hydrogeological processes, a flow animation module (FAM) has been developed within Visual KARSYS (https://www.visualkarsys.com/); a web tool dedicated to 3D conceptual modelling of complex aquifers. Concepts and principles of 3D conceptual models and of the new FAM are presented and discussed in this paper with an application to a volcanic aquifer in Indonesia. [ABSTRACT FROM AUTHOR]

While it is well accepted that climate change and growing water needs affect long-term sustainable water resourcesmanagement, performing accurate simulations of water cycle and energy balance dynamics at regional scale remains a challenging task. Traditional Soil-Vegetation-Atmosphere-Transfer (SVAT) models are used for numerical surface water and energy simulations. These models, by conception, do not account for the groundwater lower boundary that permits a full hydrosystem representation. Conversely, while addressing important features such as subsurface heterogeneity and river-aquifer exchanges, groundwater models often integrate overly simplified upper boundary conditions ignoring soil heating and the impacts of vegetation processes on radiation fluxes and root-zone uptakes. In this paper, one of the first attempts to jointly model water and energy fluxes with a special focus on both surface and groundwater at the regional scale is proposed on the Seine hydrosystem (78,650 km²), which overlays one of the main multi-aquifer systems of Europe. This study couples the SVAT model ORCHIDEE and the process-based hydrological-hydrogeological model CaWaQS, which describes water fluxes, via a one-way coupling approach from ORCHIDEE toward CaWaQS based on the blueprint published by de Marsily et al. [1978]. An original transport library based on the resolution of the diffusion/advection transport equation was developed in order to simulate heat transfer in both 1D-river networks and pseudo-3D aquifer systems. In addition, an analytical solution is used to simulate heat transport through aquitards and streambeds. Simulated ORCHIDEE surface water and energy fluxes feed fast surface runoff and slow recharge respectively and then is used as CaWaQS forcings to compute river discharges, hydraulic heads and temperature dynamics through space and time, within each of the hydrosystem compartments. The tool makes it possible to establish a fully consistent water and energy budget over a period of 17 years. It also simulates temperature evolution in each aquifer and evaluates that river thermal regulation mostly relies by order of importance on short wave radiations (109.3W·m-2), groundwater fluxes (48.1W·m-2) and surface runoff (22.7W·m-2). [ABSTRACT FROM AUTHOR]

Evaporation is a function of both climate conditions and other environmental conditions, including land use. In the context of large-scale environmental changes, understanding the relative impacts of each driver of past and future evaporation changes is necessary for land and water planning. While climate change impacts on evaporation can be estimated straightforwardly by original Budyko formulations, including the role of land use within these formulations remains an open question. In this paper, we collected an extensive set of 5026 worldwide catchments to parametrize a land use dependent Budyko-type formulation. By trading space for time, we then assess the potentialities of the proposed formulation in predicting the impacts of land use changes on the evaporation changes. Results show a clear modulation of land use on evapotranspiration, suggesting larger and lower evaporation rates over croplands and urban areas respectively. The proposed formulation was able to reasonably predict the magnitude of the decrease of the evaporative ratio on urbanizing catchments, but fails to efficiently predict the hydrological impacts of vegetated land use conversions, both in terms of direction and magnitude of changes. This suggests either the proposed formulation is too crude, or the underlying hypotheses of space-time trading are not valid. [ABSTRACT FROM AUTHOR]

The paper underlines the contributions of Ghislain deMarsily (GdM) to the identification of aquifers heterogeneity using inverse methods mainly for modeling subsurface flow. Inverse methods require an objective function to express the goodness of fit of the chosen model, a parameterization to describe the spatial distribution of model parameters, and a minimization algorithm. The resulting inverse problem, which consists in seeking model parameters' values that render model outputs close to the observations, is usually unstable. GdM developed seminal ideas for the two key inversion issues that are: to stabilize the inverse problem through regularization, and to parameterize it to reproduce the natural heterogeneity of the subsurface with a limited number of parameters. GdM conducted pioneering works that are the basis of current parameterization methods relying upon adaptive zonation and/or interpolation based on pilot points. We take here the opportunity to highlight the GdM's contributions inspiring currently used techniques. [ABSTRACT FROM AUTHOR]

Currently, researchers have indicated that inorganic minerals in reservoirs, such as clay minerals, carbonates and quartz, can catalyze the evolution of organic matter into oil and gas. Therefore it is reasonable to believe that the minerals in reservoirs may act as a catalyst support with the metal-containing catalyst added fromoutside during the thermal recovery of heavy oil. This paper studied the aquathermolysis of heavy oil catalyzed by minerals and transition metal. The reaction conditions of two heavy oil samples were investigated. The results show that the optimal reaction conditions of heavy oil fromXinjiang BaikouquanOilfield (XBO) are the reaction temperature of 250 °C and the reaction time of 6 h; for the crude oil from Xinjiang Tahe Oilfield (XTO), the optimal reaction conditions are determined to be the reaction temperature of 250 °C and the reaction time of 12 h, the water-oil ratio of the two oils is 0.3.Under optimal conditions, viscosity and pour point of heavy oil are significantly reduced. Differential scanning calorimetry (DSC), GC-MS analysis, thermogravimetric analysis (TGA), and elemental analysis were used to study the properties of the two heavy oil samples before and after reaction to explore themechanism of the catalyzed aquathermolysis of heavy oil. This work will benefit the related heavy oil recovery work in this field. [ABSTRACT FROM AUTHOR]

In this paper, we apply the exact controllability concept for time-harmonic electromagnetic scattering. The problem is presented in terms of the differential forms, and the discrete exterior calculus is utilized for spatial discretization. Accordingly, the physical properties of the problem are maintained. Despite we consider time-harmonic problems, we concentrate on transient wave equations treated by the exact controllability approach. Essentially, we use a controlled variation of the asymptotic approach with periodic constraints, in which the time-dependent equation is simulated in time, until the time-harmonic solution is reached. [ABSTRACT FROM AUTHOR]

A stable scheme is proposed in this paper in order to obtain approximate solutions of second-moment turbulent models for incompressible flows with or without thermal transport equation. The analysis of the convective terms, which includes the solution of the associated Riemann problem, enables to propose a standard projection scheme, and to get rid of spurious oscillations. [ABSTRACT FROM AUTHOR]

This paper presents an implementation of the c-phi reduction procedure in the finite element code Cast3M. This procedure is first validated on a simple example of bearing capacity of a strip footing and then used to evaluate the stability factor of a geotechnical structure composed of two levels of backfill retained by two retaining walls, with a road built on the top of the second backfill. The results of the c-phi reduction procedure for the construction of first and second backfill are also compared to other analysis methods classically used in geotechnics and to the results of finite element calculations. [ABSTRACT FROM AUTHOR]

This paper is devoted to recall several contributions to the numerical control of PDE's that have origin in Glowinski's work. I will consider null controllability problems for linear and nonlinear heat equations and some free-boundary systems. We will also deal with some bi-objective optimal control problems. Additionally, some new methods and results will be announced. [ABSTRACT FROM AUTHOR]

A nonlinear least-squares finite element method for strong solutions of the Dirichlet boundary value problem of a two-dimensional Pucci equation on convex polygonal domains is investigated in this paper. We obtain a priori and a posteriori error estimates and present corroborating numerical results, where the discrete nonsmooth and nonlinear optimization problems are solved by an active set method and an alternating direction method with multipliers. [ABSTRACT FROM AUTHOR]

In this work we address the reduction of face degrees of freedom (DOFs) for discrete elasticity complexes. Specifically, using serendipity techniques, we develop a reduced version of a recently introduced two-dimensional complex arising from traces of the three-dimensional elasticity complex. The keystone of the reduction process is a new estimate of symmetric tensor-valued polynomial fields in terms of boundary values, completed with suitable projections of internal values for higher degrees. We prove an extensive set of new results for the original complex and show that the reduced complex has the same homological and analytical properties as the original one. This paper also contains an appendix with proofs of general Poincaré--Korn-type inequalities for hybrid fields. [ABSTRACT FROM AUTHOR]

Although renewable energies are beneficial to reduce carbon emissions, its intermittent characteristics may result in power-supply issues in distribution grid. Battery energy storage system is generally regarded as an effective tool to deal with them. On the other hand mathematical modelling, numerical simulation, optimization and control theory are nowadays of paramount importance to handle this kind of problems and related issues. In this paper we present a methodology for the development of bidding strategies and real-time control for electricity producers in a competitive electricity marketplace. Firstly, a stochastic model of a wind power plant with battery storage is stated in the framework of stochastic differential equations (SDE). Then, a stochastic control problem with state constraints is introduced and the corresponding optimality conditions involving the Hamilton--Jacobi--Bellman equation are deduced. For this purpose, advantage is taken from the fact that optimal control problems for stochastic ordinary differential equations (SDE) can be equivalently formulated as optimal control problems for deterministic partial differential equations (PDE), namely, the corresponding Fokker--Planck equation. [ABSTRACT FROM AUTHOR]

We introduce two finite element formulations to approximate magneto-static problems with discontinuous electric potential based respectively on the electrical scalar potential and the magnetic field. This work is motivated by our interest in Liquid Metal Batteries (LMBs), a promising technology for storing intermittent renewable sources of energy in large scale energy storage devices. LMBs consist of three liquid layers stably stratified and immiscible, with a light liquid metal on top (negative electrode), a molten salt in the middle (electrolyte) and a heavier liquid metal on bottom (positive electrode). Energy is stored in electrical potential differences that can be modeled as jumps at each electrode-electrolyte interface. This paper focuses on introducing new finite element methods for computing current and potential distributions, which account for internal voltage jumps in liquid metal batteries. Two different formulations that use as primary unknowns the electrical potential and magnetic field, respectively, are presented. We validate them using various manufactured test cases, and discuss their applications for simulating the current distribution during the discharge phase in a liquid metal battery. [ABSTRACT FROM AUTHOR]

Soft bending actuators show high adaptability for applications such as rehabilitation or grasping. Although constant curvature assumption has been extensively used for free motion modeling, these actuators do not bend circularly when interacting with the environment. In such situation, conventional bending sensors cannot provide useful information on their shape. In this paper, the Finite Rigid Elements approach is utilized to model the behavior of a soft pneumatic bending actuator in free motion and contact. With this method, the variable curvature configuration under different external loads can be modeled. Then, the contact force between the actuator and an object located in a specific position is estimated utilizing the Gradient Descent optimization method. Experimental results verified the combinatorial proposed approach for both force estimation and structure deformation. [ABSTRACT FROM AUTHOR]

This paper aims at providing exact expressions for the mechanical fields induced by Laser Shock Peening and comparing them to their numerical estimations. We use a uniaxial strain field hypothesis with an elastic perfectly plastic behavior to derive the stress wave equation. An exact solution to this equation is given using the method of characteristics for a step time profile for the pressure loading, and numerically using finite differences schemes adapted for this hyperbolic equation. An additional residual stress modeling is used, providing the residual stress distribution assuming a planar infinite plate with a finite thickness. Results are presented for three loading pressures, each one corresponding to a different structure in the exact solution. The exact and numerical results present a good match, allowing either the use of the exact solution for an initial estimation of the mechanical fields, or to test the accuracy of other numerical methods. [ABSTRACT FROM AUTHOR]