Science & Mathematics

This study deals with experimental methods dedicated to the determination of the liquid chemical potential in heterogeneous media. Various measurement techniques are proposed including a new mechanical method based on the expansion of the air-vapor atmosphere surrounding a sample. From the large range of materials under investigation (soil, wood, gel, agro-product, biological tissue), various micro-structures are investigated. Thus, liquid/solid interactions occurring at the interface scale involve several physico-chemical phenomena that can all be interpreted through the concept of chemical potential. The dependence of the liquid chemical potential on the liquid content is established over the whole range of energy. Eventually, extrapolation of the results towards the low values of chemical potential is analyzed and a modeling approach is proposed. Even if the results presented concerns essentially a water phase, the principles are applicable to several other fluids.

Both preclinical and clinical studies have shown that immune activation and inflammation during the early stages of neurodevelopment increase the risk of neurodevelopment disorders and behaviour abnormalities in adults. While the underlying mechanisms have only been partially elucidated, experiments in the maternal immune activation mouse model (MIA) – in which pregnant dams are injected with the viral mimic poly(I:C) – have demonstrated the critical role of two cytokines: interleukin (IL)-6 and IL-17A. However, the vast majority of the studies performed to date have used behavioural tests in adult mice as a read out to study the impact of cytokines on neurodevelopment. Therefore, it is not clear whether altered levels of other cytokines during the perinatal period could impact neurodevelopment and behaviour in infant mice. To address this issue, we have analysed the progeny of several cohorts of poly(I:C)- and saline-injected mothers for behaviour between postnatal day 5 (P5) and P15 and serum cytokine levels at P15. Because both perinatal neurodevelopment and cytokine production are known or believed to be impacted by many environmental variables, we analysed our data using a multivariable statistical model to identify features associated with being born to a poly(I:C)-injected mother (as opposed to being born to a saline-injected mother). We found that the drop of body weight and temperature of the mother after poly(I:C) injection, the litter size, the pup weight at P15, the number of ultrasonic vocalizations (USV) emitted by the pup at P6, the distance travelled by the pup and the time it spent mobile at P13, as well as serum levels of Tumour Necrosis Factor (TNF), IL-5, IL-15 and C-X-C motif chemokine (CXCL)10 were all associated with altered odds of being born to a poly(I:C)-injected mother. To further explore the role of TNF during the early postnatal period, we injected mouse pups daily from P1 to P5 and assessed these animals for both developmental milestones and behaviour from P8 to P15. Unexpectedly, injection of recombinant TNF did not have a detrimental impact on neurodevelopment but rather promoted sensorimotor reflexes acquisition and exploratory behaviour. Altogether, our results confirm that cytokines play a critical role during neurodevelopment and that altered levels of specific cytokines, and in particular TNF, could regulate the acquisition of developmental milestones and behaviour in infant mice. While we have only obtained preliminary insights into underlying mechanisms, the protocols that we have developed provide a framework for further studies.

This paper discusses several issues of evaluation and comparison of anomaly detection algorithms, namely lack of publicly available implementations and annotated data sets. Another problem of many methods is a detection delay caused by operating on data binned to a long time intervals. The paper presents a library under development which aims to tackle the comparison and evaluation issues. Further, the paper proposes a novel anomaly detection approach that can contribute to anomaly detection in real-time.

Background: Many important evolutionary adaptations originate in the modification of gene regulatory circuits to produce new gene activity phenotypes. How do evolving populations sift through an astronomical number of circuits to find circuits with new adaptive phenotypes? The answer may often involve phenotypic plasticity. Phenotypic plasticity allows a genotype to produce different - alternative - phenotypes after non-genetic perturbations that include gene expression noise, environmental change, or epigenetic modification. Results: We here analyze a well-studied model of gene regulatory circuits. A circuit's genotype encodes the regulatory interactions among circuit genes, and its phenotype corresponds to a stable gene activity pattern the circuit forms. For this model, we study how genotypes are arranged in genotype space, where the distance between two genotypes reflects the number of regulatory mutations that set those genotypes apart. Specifically, we address whether this arrangement favors adaptive evolution mediated by plasticity. We find that plasticity facilitates the origin of genotypes that produce a new phenotype in response to non-genetic perturbations. We also find that selection can then stabilize the new phenotype genetically, allowing it to become a circuit's dominant gene expression phenotype. These are generic properties of the circuits we study here. Conclusions: Taken together, our observations suggest that phenotypic plasticity frequently facilitates the evolution of novel beneficial gene activity patterns in gene regulatory circuits.

The study of the mathematics and geometry of ancient civilizations is a task which seems to be very difficult or even impossible to fulfil, if few written documents, or none at all, had survived from the past. However, besides the direct information that we can have from written documents, we can gain some indirect evidence on mathematics and geometry also from the analysis of the decorations we find on artifacts. Here, for instance, we will show that ancient Egyptians were able of making geometric constructions using compass and straightedge, quite before the Greek Oenopides of Chois, who lived around 450 BC, had declared some of their basic principles. In fact, a wood panel covered by an overlapping circles grid pattern, found in the tomb of Kha, an architect who served three kings of 18th Dynasty (1400-1350 BC), evidences that some simple constructions with compass and straightedge were used in ancient Egypt about nine centuries before Oenopides' time.

Although the alien Impatiens glandulifera successfully invades riparian habitats and is visited by native insects, knowledge of its impact on native bees is limited. We assessed pollinator abundance in field sites where I. glandulifera was absent, present or had been experimentally removed. We measured insect visitation to flowers of potted native plants and to I. glandulifera. Bombus spp. comprised the highest proportion of visitors in invaded sites, whereas solitary bees made up the highest proportion in sites where I. glandulifera was removed. More bees, especially medium- and long-tongued Bombus spp. (B. pascuorum and B. hortorum), foraged on I. glandulifera than the native plant species (possibly because the alien was more abundant). We detected no impact of invasion on standardised pollinator abundance, B. pascuorum abundance, nor functional insect diversity, which may be due to variable climatic conditions. We suggest that future studies focus on impacts on rare or specialised pollinator taxa.

L’étude archéothanatologique de près de 700 tombes au sein de la civitas de Forum Iulii a engendré une nouvelle réflexion sur la typo-chronologie. Cette analyse révèle certaines spécificités au regard de la documentation de la Gaule Narbonnaise, en lien avec l’histoire locale. En effet, dans un premier temps, l’apparition de certains dispositifs de manière relativement précoce témoigne d’une pratique spécifique introduite par des groupes nouvellement installés par Rome dès le ier s. av. J.-C. (déductions viritanes ou colons). Ce n’est ensuite que dans un second temps, qu’il est possible d’aborder la diffusion de ces dispositifs au sein du territoire. L’analyse typochronologique des tombes contribue ainsi à une meilleure connaissance de l’histoire socio-culturelle des populations du Haut-Empire.

This note shows that there are close connections between the determinacy of a stationary state equilibrium and its stability under learning whenever agents try to estimate both the law of motion of the state variable and the stationary state value.

13x18 cm, plaque de verre

Introduction : la stéatopathie métabolique est une des atteintes hépatiques chroniques les plus fréquentes dans les pays développés. Il existe un débat dans la littérature concernant le rôle de la stéatopathie métabolique en tant que facteur indépendant de risque cardiovasculaire. La relation entre la stéatose hépatique non alcoolique et l’athérosclérose n’est pas encore éclaircie. Objectif : dans cette étude, nous avons voulu déterminer si la stéatopathie métabolique était associée à l’athérosclérose chez les patients présentant plusieurs facteurs de risques cardiovasculaires. Matériel et méthodes : nous avons étudié un total de 80 patients avec au moins deux facteurs de risques cardiovasculaires, 39 patients atteints de stéatopathie métabolique, diagnostiquée via l’élastométrie impulsionnelle associée au « controlled attenuation parameter (CAP) » et 41 patients sans stéatopathie métabolique qui était comparable pour l’âge et le sexe. Nous avons comparé chez les deux groupes plusieurs marqueurs d’athérosclérose (épaisseur intima-média (EIM), plaques athéromateuses carotidiennes, diamètre de l’aorte et index de pression systolique (IPS)). Résultats : les deux groupes étaient comparables pour les différentes caractéristiques, cliniques et biochimiques, seule la présence de la stéatopathie métabolique permettait de les distinguer. Il n’y a pas de différence significative entre les deux groupes concernant la valeur des EIM droite et gauche, concernant le degré de sténose des plaques athéromateuses carotidiennes, concernant le diamètre de l’aorte ou les mesure d’IPS. Conclusion : cette étude suggère qu’il n’y a pas de lien entre la stéatopathie métabolique et les différents marqueurs de l’athérosclérose chez les patients présentant plus de deux facteurs de risques cardiovasculaires.

At the demand of SNCF, an experimental study of electrical circuit shunting phenomenon has been led together by LGEP-Supelec and IFSTTAR on a scaled rolling test bench. The electrical measurements have shown a non linear behavior identified as a Branly effect.

More than 15 years after the launch of the Abdali project, many buildings are empty and signs "for lease" abound.

Equipment condition monitoring of nuclear power plants requires to optimally group the usually very large number of signals and to develop for each identified group a separate condition monitoring model. In this paper we propose an approach to optimally group the signals. We use a Genetic Algorithm (GA) for the optimization of the groups; the decision variables of the optimization problem relate to the composition of the groups (i.e., which signals they contain) and the objective function (fitness) driving the search for the optimal grouping is constructed in terms of quantitative indicators of the performances of the condition monitoring models themselves: in this sense, the GA search engine is a wrapper around the condition monitoring models. A real case study is considered, concerning the condition monitoring of the Reactor Coolant Pump (RCP) of a Pressurized Water Reactor (PWR). The optimization results are evaluated with respect to the accuracy and robustness of the monitored signals estimates. The condition monitoring models built on the groups found by the proposed approach outperform the model which uses all available signals, whereas they perform similarly to the models built on groups based on signal correlation. However, these latter do not guarantee the robustness of the reconstruction in case of abnormal conditions and require to a priori fix characteristics of the groups, such as the desired minimum correlation value in a group.