Science & Mathematics

Two new species of Paraplonobia Wainstein and Eurytetranychus Oudemans are described from Iran: Paraplonobia (Paraplonobia) flechtmanni n. sp. from Russian knapweed Rhaponticum repens (Asteraceae) and Eurytetranychus aminii n. sp. from gum bushes Astragalus gossypinus (Fabaceae). We describe all life stages of Eutetranychus orientalis (Klein) and discuss variation within this polyphagous pest species. A key to all known species of the genus Paraplonobia (Paraplonobia) is given.

Il s'agit d'un groupe de trois hommes.

Glasses are commonly described as disordered counterparts of the corresponding crystals; both usually share the same short-range order, but glasses lack long-range order. Here, a quantification of chemical bonding in a series of glasses and their corresponding crystals is performed, employing two quantum-chemical bonding descriptors, the number of electrons transferred and shared between adjacent atoms. For popular glasses like SiO 2 , GeSe 2 , and GeSe, the quantum-chemical bonding descriptors of the glass and the corresponding crystal hardly differ. This explains why these glasses possess a similar short-range order as their crystals. Unconventional glasses, which differ significantly in their short-range order and optical properties from the corresponding crystals are only found in a distinct region of the map spanned by the two bonding descriptors. This region contains crystals of GeTe, Sb 2 Te 3 , and GeSb 2 Te 4 , which employ metavalent bonding. Hence, unconventional glasses are only obtained for solids, whose crystals employ theses peculiar bonds.

Pour tenter une nouvelle fois de résoudre les difficultés des entreprises d'Etat, les représentants du Parti, réunis en 15ème Congrès à Pékin à la mi-septembre 1997, ont affirmé le principe de l'ouverture de leur capital. Ce principe était déjà à l'œuvre dans de nombreuses villes. Les départements et administrations dont dépendaient les entreprises pouvaient décider de mettre en vente tout ou partie de leur capital pour financer la modernisation technologique ou pour se débarrasser des plus déficitaires. Cette vente d'actifs de l'Etat prend place dans un processus de transformation des entreprises d'Etat en sociétés par actions. Cette politique marque une accélération des réformes, mais s'inscrit aussi dans le prolongement des précédentes...

Mars is a hyperarid, global cryosphere, and likely has been for over 3 Gyr. Contrastingly, during the so-called early Mars period 4-3.5 Gyr go, water flowed within thousands of valleys, in crater lakes, producing ancient deltas, building ice sheets, and possibly ponding in oceans [1]. However, this early benign climate collapsed with the continued loss of Mars’ atmosphere in the Hesperian period, ~3.5-3 Gyr ago. Activity in most outflow channels has been dated from this period [1-3], with some channels displaying younger [2] and/or later [3] erosive episodes. Within the channels there are landforms indicative of the flow of massive amounts of fluid, including streamlined islands and longitudinal grooves and ridges, often seen diverging around obstacles. Among the outflow channels, Kasei Valles is of particular interest because of its large size, as the volume of water involved in its formation could have contributed substantially to the existence of a northern ocean [2-3] (figure 1c). Owing to the similar landforms carved by the Missoula megafloods observed in the Channeled Scablands on Earth [1,4] (figure 2, c and f), Kasei Valles along with other martian outflow channels is analogously interpreted to be the result of ancient massive outburst floods [1-4]. Support for this hypothesis includes the presence and morphology of streamlined islands, the presence of regularly spaced longitudinal ridges, and the presence of hanging valleys and U-shaped valleys [1,4,5]. Debate ensues, however, regarding the near surface stability and availability of liquid water during the Hesperian period required to produce repeated erosion at the scales of observed in Kasei Valles. Alternative hypotheses that could explain outflow channel formation include ice streaming [5-6] or regional construction and local erosion by turbulent lava flows [7].Figure 1. (a) Global topography of Mars with outflow channel distribution. (b) Timeline of Earth (top) and Mars (bottom) highlighting the origin of life on Earth (green star) and the evolution of Mars’ climate and hydrology through time, and the moment of outflow channel incision coinciding the collapse of the early water-bearing climate. (c) Kasei Valles, the largest outflow channel. (d) Hesperian outflow channels, marking the landing site of ESA’s ExoMars Rosalind Franklin Rover, which will search of evidences of life (red circle on Oxia Planum).This project aims to explore the contrasting hypothesis that Kasei Valles was eroded by an ice stream [5-7], a region of channelized, fast-flowing ice within an ice sheet, and reinvestigate the origin of other outflow channels under this perspective. Drawing from fluid dynamic simulations, analogue field work, geological mapping, and climate modelling, the objective is to test the ice sculpture hypothesis first raised by Baerbel Lucchitta (1982) [5-6], which if correct, would substantially impact our understanding of Mars’ transitional Hesperian climate, the nature of its hydrological cycle, and the possibility of a Hesperian ocean.Our preliminary observations and results tentatively support this hypothesis [8]. In terms of geomorphology, we show that bedforms such as grooves and streamlined islands, spatial scales, cross-section geometry, and planform morphology all are consistent with terrestrial ice streams, even more so than with the classical analogue of the Channeled Scablands (figure 2, compare a&d with b&e and c&f). Moreover, Kasei Valles demonstrates a lack of significant landforms associated with turbulent flow, such as kolks, turbulent eddie marks, or labyrinthine terrain, which are well visible and reported for the Channeled Scablands as well as other megaflood-type landscapes [4].Fig 2. Overview and comparative of Kasei Valles and analogue sites and processes. (a) Kasei Valles (MOLA elevation on hillshade). (b) Graphic outline of the northeast Greenland ice stream. (c) Outline of the Channeled Scablands (US) adapted from the USGS. (d) Longitudinal grooves in Kasei Valles (CTX mosaic). (e) Megascale glacial lineations and megagrooves, Dubawnt Lake ice stream bed (ArcticDEM hillshade). (f) Grooves carved by Missoula megaflood, Channeled Scablands (Maxar, Google Earth, contrast-stretched). We use fluid dynamic simulations to analyze, explain, and interpret the scale and bedforms that are observable within and around Kasei Valles, and then consider comparisons with relevant terrestrial analogues beyond the classic Channeled Scablands site as well as geomorphological characteristics of fast-flowing glacial bodies, to draw conclusions regarding the origin of Kasei Valles, and implications for other outflow channels [8]. Finally, we will contextualize its climatic implications during the time of climate collapse (figure 1) at the end of the Hesperian period, following previous work [10].Acknowledgements. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon Europe research and innovation programme (Grant agreement No. 101165197 - ICEFLOODS).References: [1] Carr M.H. (2007) C.U.P (Vol.6). [2] Chapman M.G. et al. (2010a) EPSL, 294 (3-4). [3] Chapman M.G., et al. (2010b). [4] Baker, V.R. and Milton, D.J., (1974) Icarus, 23(1), 27-41. [5] Lucchitta B.K. (1982) JGR: Solid Earth 87(B12). [6] Lucchitta B. K. (2001) GRL, 28(3), 403-406. [7] Leverington D.W. (2011) Geomorphology 132(3-4) [8] Grau Galofre et al., 2023, LPSC. [9] Stokes C.R. and Clark, C.D. (2001) Quaternary Sci. Rev. 20(13). [10] Turbet et al., 2017 Icarus 288, 10–36.

Each day, accidents involving hazardous materials are managed by Emergency Services. In order to bring the best adapted operational answer, it is necessary to determine with accuracy the concentrations of the gas to which people will be exposed. The expert in charge of modeling is facing a major difficulty: few (or no) information. Therefore, for a given situation, the generation of different effect distances is possible. A sensitivity analysis was carried out in order to determine the most influential parameters on the estimation of safety distances. The goal is to identify the parameters for which it is necessary to pay a very detailed attention. The first step of the study was to define the system to be analyzed. The second step consisted in working out a complete model of evaluation of safety distances in emergency situation. This was done by combining an existing dispersion model (SLAB) with a specifically developed application for the calculation of input parameters. The input data are operational data which can be collected from the accident site and the output data are safety distances. The third step consisted in selecting two test cases representative of an accident situation involving hazardous chemicals (leak on a wagon of ammonia and a wagon of propane). After that, it was characterizing the range of possible values of the whole input parameters. A fourth step consisted in applying two methods of sensitivity analysis: a screening method (MORRIS's method) and a local sensitivity analysis. Finally, the application of these methods, on the same case study, made it possible to highlight the points of convergence of the methods and their advantages. Finally, the parameters for which it is useless / useful to initiate considerable efforts to recover a reliable value were highlighted.

La technologie IP autrefois utilisée uniquement dans le cadre d'Internet est de nos jours le support de nombreuses autres applications dé-corrélées telle que la téléphonie ou encore la télévision. Cette multi-utilisation du standard a entraîné une volonté de mutualisation au sein du coeur de réseau. Aujourd'hui, les fonctionnalités apportées par MPLS permettent une virtualisalisation des infrastructures de réseau IP sur un unique coeur , entraînant une complexification de la gestion de la ressource. Dans cette thèse, nous étudierons les possibilités actuelles de gestion de ce réseau mutualisé et nous proposerons l'adjonction d'un mécanisme de gestion appelé TDCN. Nous démontrerons les nombreuses possibilités offertes par ce nouveau système pour ainsi optimiser l'utilisation du réseau.

Majority voting aggregates individual preference profiles into a binary relation on the set of alternatives. Condorcet cycles are cycles of the aggregated binary relation. We show that the relative volume of the subset of the (n!−1)-simplex that represents profile distributions such that the aggregated preferences display Condorcet cycles is a decreasing function of the super majority levelτbounded by the expressionThis expression shows that Condorcet cycles become rare events for super majority rules larger than 53%.

24x36 mm, gélatine plan-film.

Mechanically improved polymeric membranes with high ionic conductivity (IC) and good permeability are highly desired for next-generation anion exchange membranes (AEMs) in order to reduce Ohmic losses and enhance water management in alkaline membrane fuel cells. To move towards the fabrication of such high-performance membranes, the creation of hydrophilic ion-conducting double gyroid (DG) nanochannels within block copolymer (BCP) AEMs is a promising approach. However, this attractive solution remains difficult to implement due to the complexity of constructing a well-developed ion-conducting DG morphology across the entire membrane thickness. To deal with this issue, water permeable polystyrene-block-poly(2-vinylpyridine)-block-poly(ethylene oxide) membranes with ion-conducting DG nanochannels were produced by combining a solvent vapor annealing (SVA) treatment with a methylation process. Here, the SVA treatment enabled the manufacture of DG-forming BCP AEMs while the methylation process allowed for the conversion of pyridine sites to N-methylpyridinium (NMP+) cations via a Menshutkin reaction. Following this SVA-methylation method, the IC value of water-permeable (~384 L h−1 m−2 bar−1) DG-structured BCP AEMs in their OH−counter anion form was measured to be of ~2.8 mS.cm−1 at 20 °C while a lower IC value was probed, under the same experimental conditions, from as-cast NMP+-containing analogs with a non-permeable disordered phase (~1.2 mS.cm−1).

Understanding the behaviors and intentions of humans is still one of the main challenges for vehicle autonomy. More specifically, inferring the intentions and actions of vulnerable actors, namely pedestrians, in complex situations such as urban traffic scenes remains a difficult task and a blocking point towards more automated vehicles. Answering the question "Is the pedestrian going to cross?" is a good starting point in order to advance in the quest to the fifth level of autonomous driving. In this paper, we address the problem of real-time discrete intention prediction of pedestrians in urban traffic environments by linking the dynamics of a pedestrian's skeleton to an intention. Hence, we propose SPI-Net (Skeleton-based Pedestrian Intention network): a representation-focused multi-branch network combining features from 2D pedestrian body poses for the prediction of pedestrians' discrete intentions. Experimental results show that SPI-Net achieved 94.4% accuracy in pedestrian crossing prediction on the JAAD data set while being efficient for real-time scenarios since SPI-Net can reach around one inference every 0.25 ms on one GPU (i.e., RTX 2080ti), or every 0.67 ms on one CPU (i.e., Intel Core i7 8700K).