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International audience; The purpose of this note is to present the effects induced on the dynamics of a linear system using a derivative operator which is implemented by means of a delay-difference approximation. In this sense, a linear time-invariant (LTI) single-input/single-output (SISO) system is considered, subject to a PD-type controller for which the derivative action was implemented by considering the aforementioned mechanism. The use of such a methodology leads to a characteristic function with coefficients that explicitly depend on the delay parameter. This note presents sufficient conditions under which the approximation leads to unstable (real) roots, showing explicitly the sensitivity of the approximation with respect to "small" delays. Several illustrative examples complete the presentation.

International audience; This paper focuses on the study of the behavior of critical roots when a dynamical system is stabilized by a PD-controller, for which the derivative action has been approximated by using two commensurate delays. The use of such an approximation leads to a characteristic quasipolynomial whose coefficients depend explicitly on the delay parameter. The aim of the paper is to address the way the delay parameter may affect the location of the roots of the corresponding characteristic function, and in particular the cases when "small" delays induce instability in the closed-loop systems. Such an analysis is performed by expressing the critical solution of the system as a delay-dependent power series. Illustrative examples complete the presentation.

International audience; Virtual Reality (VR) applications are employed in engineering situation to simulate real and artificial situations where the user can interact with 3D models in real time. Within theseapplications the virtual environment must emulate real world physics such that the system behaviour and interaction are as natural as possible and to support realistic manufacturing applications. As a consequence of this focus, several simulation engines have beendeveloped for various digital applications, including VR, to compute the physical response and body dynamics of objects. However, the performance of these physics engines within haptic-enabled VR applications varies considerably. In this study two third party physics engines - Bullet and PhysXtm- are evaluated to establish their appropriateness for haptic virtual assembly applications. With this objective in mind five assembly tasks were created with increasing assembly and geometry complexity. Each of these was carried out using the two different physics engines which had been implemented in a haptic-enabled virtual assembly platform specifically developed for this purpose. Several physics-performance parameters were also defined to aid the comparison. This approach and the subsequent results successfully demonstrated the key strengths, limitations, and weaknesses of the physics engines in haptic virtual assembly environments.

International audience; Virtual assembly platforms (VAPs) provide a means to interrogate product form, fit and function thereby shortening the design cycle time and improving product manufacturability while reducing assembly cost. VAPs lend themselves to training and can be used as offline programmable interfaces for planning and automation. Haptic devices are increasingly being chosen as the mode of interaction for VAPs over conventional glove-based and 3D-mice, the key benefit being the kinaesthetic feedback users receive while performing virtual assembly tasks in 2D/3D space leading to a virtual world closer to the real world. However, the challenge in recent years is to understand and evaluate the addedvalue of haptics. This paper reports on a haptic enabled VAP with a view to questioning the awareness of the environment and associated assembly tasks. The objective is to evaluate and compare humanperformance during virtual assembly and real-world assembly, and to identify conditions that may affect the performance of virtual assembly tasks. In particular, the effect of weight perception on virtual assembly tasks is investigated.

The human default mode network (DMN) is engaged at rest and in cognitive states such as self-directed thoughts. Interconnected homologous cortical areas in primates constitute a network considered as the equivalent. Here, based on a cross-species comparison of the DMN between humans and non-hominoid primates (macaques, marmosets, and mouse lemurs), we report major dissimilarities in connectivity profiles. Most importantly, the medial prefrontal cortex (mPFC) of non-hominoid primates is poorly engaged with the posterior cingulate cortex (PCC), though strong correlated activity between the human PCC and the mPFC is a key feature of the human DMN. Instead, a fronto-temporal resting-state network involving the mPFC was detected consistently across non-hominoid primate species. These common functional features shared between non-hominoid primates but not with humans suggest a substantial gap in the organization of the primate's DMN and its associated cognitive functions.

Hydrothermal carbonization (HTC) of Agave Salmiana bagasse was investigated to assess the potential of hydrochar as an energy resource. The effect of operating conditions on the mass yield and the energy quality of hydrochar was examined by varying the temperature and the holding time over the ranges of 180–250 ℃ (T) and 0–60 min (t), respectively. These parameters were screened using the response surface methodology through a Doehlert design. Performances of HTC were assessed on the basis of the hydrochar mass yield higher heating value ultimate and proximate analyses. In the studied domain, the modeling results indicated that the hydrochar mass yield varies between 45% and 86% and higher heating valuesfrom18 to 23 MJ.kg-1, which is similar to that of peat. In addition, the volatile matter and fixed carbon fractions of hydrochars ranged from 54 to 80% and between 12 and 36%, respectively. Energy yield modeling indicated that the mass yield is the most influent parameter. The maximal energy yield value was obtained at 180 ℃ with time equal to 0 min. Globally, the evolution of H/C ratio is amplified for temperatures greater than 215 ℃ by increasing the holding time from 30 to 60 min. For O/C ratio the maximal variation is below these conditions. It is concluded that increased hydrothermal carbonization conditions favor dehydration reactions, while decarboxylation reactions are favored in mild HTC conditions. The combustion characteristics such as ignition peak and burnout temperatures were significantly modified for hydrochars. The model results indicated that lowest ignition and peak temperature values are obtained at both low-temperature and low-holding time, and high-temperature and high-holding time zones. An increase in the burnout temperature was correlated with the increase of the fixed carbon content in hydrochars.

In this paper, we introduce a codification of the paths towards synchronization for synchronizing flows defined over a network. The collection of paths toward synchronization defines a combinatorial structure: the transition diagram. We describe the transition diagram corresponding to the Laplacian flow over the completely connected graph. This applies to the Kuramoto flow over the same graph when initial conditions close to the diagonal are considered. We present as well some results concerning the Laplacian and Kuramoto flows over the complete bipartite graph.

International audience; Here, we unveil the great potential of metal-organic framework (MOF) composite fibers produced by the electrospinning method to remove D4 siloxane from gaseous solutions. The fibers are based on polyacrylonitrile (PAN) and a microporous aluminum-based MOF known as DUT-4. The electrospinning configuration and DUT-4:PAN ratio in the precursor solutions play an important role in the textural properties of the fibers. Characterizations of morphology and textural properties demonstrated that the best dispersion on the fiber surface was achieved using coaxial electrospinning with a relationship of 1:1.4 of DUT-4:PAN. The Al-MOF fiber composite was evaluated as a D4 siloxane adsorbent, reaching over 85% of the D4 siloxane uptake capacity of individual DUT-4 crystals but with faster adsorption kinetics (effective diffusion coefficient 3.31 times higher). In addition, the synthesis of the composite showed a lower environmental impact and better thermal stability than that observed for DUT-4. This work shows the novel DUT-4 fibers have an outstanding potential for siloxane removal from biogas streams.

International audience; This paper presents a guided tour of some specific problems encountered in the stability analysis of linear dynamical systems including delays in their systems' representation. More precisely, we will address the characterization of multiple roots of the corresponding characteristic function with a particular emphasis on the way these roots are affected by the system's parameters and the way that they can be used to control. The paper covers several approaches (perturbation techniques, hypergeometric functions) leading to some methods and criteria (frequency-sweeping, multiplicity-induced-dominancy) that can be implemented (software toolboxes) for analyzing the qualitative and quantitative properties induced by the delays and other parameters on the system's dynamics. A particular attention will be paid to the so-called partial pole placement method based on the multiplicity-induced-dominancy property. The presentation is as simple as possible, focusing more on the main intuitive ideas and appropriate mathematical reasoning by analogy in the presentation of the theoretical results as well as their potential use in practical applications. Illustrative examples complete the paper.

International audience; This article focuses on the root behavior of the characteristic function of some LTI SISO systems controlled by a PD-control when a delay-difference operator is used to approximate the derivative action. We will focus on the cases when the corresponding stability problem is improperly posed for “small” delay values. In this context, we will express the solutions of the corresponding characteristic function as power series and exploit their structure in deriving the asymptotic behavior of the characteristic roots. This analysis will allow detecting and explicitly characterizing the cases when delay-difference approximations lead to improperly posed stability problems. Furthermore, in the case when the derivative approximation guarantees the properly posedness of the closed-loop system, the robustness of the scheme with respect to the delay margin of the delay-difference approximation and control gains parameters are explicitly addressed. More precisely, upper bounds on the delays as well as the robustness of the corresponding controller are computed. Some illustrative examples complete the presentation.

International audience; Mean and diam-mean equicontinuity are dynamical properties that have been of use in the study of non-periodic order. We show that the Pacman automaton is not almost diam-mean equicontinuous (it is already known that it is almost mean equicontinuous).

Despite cobalt and iron−carbon interactions playing an important role in environmental chemistry activities, major questions are still unresolved on the prevailing mechanism, surface state, required structure, and the origin of apparent particle size dependence in carbon nanotube synthesis or other heterogeneous catalytic process such as Fischer−Tropsch (F−T) synthesis. In this paper, we focus our attention on well-defined bimetallic FeCo clusters embedded in a carbon matrix to study separately size, alloy, and interface effects on physical properties. First the size-dependent evolution of the intrinsic structural and magnetic properties was estimated by using density-functional ab initio calculations for relaxed B2 (CsCl-like) FeCo nanoclusters. Then, assemblies of mass-selected clusters preformed in the gas phase by using the low-energy cluster beam deposition (LECBD) technique and coated with a carbon film were investigated by use of various experimental techniques that include transmission electron microscopy (TEM) and superconducting quantum interference device (SQUID) magnetometry as well as synchrotron techniques such as extended Xray absorption fine structure (EXAFS) and X-ray magnetic circular dichroism (XMCD). All these results show that the carbon solubility is a size-dependent process and that annealing allows us to reach the chemically ordered B2 phase only for FeCo nanoparticles larger than 5 nm in diameter., Support is acknowledged from the International Research Network (IRN)/Groupement de Recherche International (GDRI) on Nanoalloys.

International audience; This work focus on the asymptotic behavior of critical roots of linear time-delay systems with delay-dependent coefficients. Our main goal is to derive a simple methodology to characterize some ill-posed cases from the open literature. In order to accomplish such a task, our main tool will be to express the solutions as a convergent power series. More specifically, by means of an appropriate change of variable, the expansion of unbounded solutions is obtained, which allows to derive an appropriate auxiliary solution that serves to analyze the behavior of such solutions. One of the main benefits in adopting such an approach, is that stability analysis in the ill-posed cases can also be covered.

International audience; Model-free and model-fitting kinetic approaches were used to investigate the hydrothermal carbonization (HTC) of avocado stone. The total solid mass yield was used to estimate the kinetic parameters and reaction mechanism. The results obtained show that the HTC process for avocado stones could be divided into four temperature zones. Up to 160 °C, the initial induction period where the reaction rate is relatively slow. The second zone (160 to 200 °C) corresponds to the maximum decomposition rate. The third zone between 200 and 220 °C corresponds to the stabilization zone; in this zone, the total solids yield is practically constant, and finally, the polymerization zone, between 220 and 250 °C, where an increase in total solid yield was observed. The kinetic parameters and reaction mechanism were determined in two temperature zones, from 150 to 210 °C and 210 to 250 °C. In the first zone, the decomposition of avocado stone during the HTC process followed a random nucleation reaction mechanism (Avrami-Erofeev-1) with the activation energy of 87.84 ± 3.28 kJ/mol. In contrast, in the second zone, it followed a first-order reaction model, and the activation energy was 230.96 ± 28.84 kJ/mol. Analysis of PAHs with gas chromatography-mass spectrometry showed that the number of PAHs in the hydrochar increases with an increase in temperature from 190 to 250 °C. The 3–4 rings PAHs were dominant in the hydrochars prepared at temperatures between 230 and 250 °C, while two rings were largely prevalent in the hydrochar obtained at low temperatures.

This thesis studies the use of delay-based controllers for dynamical systems. Applications, experimentation, and theoretical problematics are addressed. The main focus of the study is the conception of delay-based controllers inspired by the well-known PID controllers. Also, and equally important, we study the design of such controllers. More precisely, we develop methods to find the proper choice of the controller's parameters assuring stability for different types of controllers. To this end, the thesis embraces the use of linear differential models and analysis due to its elegant frequency-based interpretation. In this regard, the stability properties of these systems are governed by their characteristic equation, which for time-delay systems are the so-called quasi-polynomials or polynomials with constant coefficients. Thus, this thesis studies the behavior of the roots of these functions with respect to variations of their parameters (coefficients and time delay values) through well-known roots crossing stability. Numeric methods and analytical observations are developed in this sense. In particular, we study applications, dc/dc converters, the Furuta pendulum, haptic devices, and the MPPT-PV (maximum power point tracking - photovoltaic) problem. Through the use of the proportional-delayed, proportional-delay-based derivative, proportional-delayed integral, and proportional-delayed-integral controllers. Also, we propose a solution to the classical delay-based control problem of stabilizing a chain of any number of oscillators by applying a single delay block.; Cette thèse étudie l'utilisation de contrôleurs basés sur le retard pour les systèmes dynamiques. Quelques applications, quelques expériences, ainsi que des problèmes et des solutions théoriques sont abordés. L'accent principal de l'étude est mis sur la conception de contrôleurs basés sur le retard inspirés des contrôleurs PID. Plus précisément, nous développons des méthodes pour trouver le bon choix des paramètres du contrôleur assurant la stabilité pour différents types de contrôleurs. À cette fin, la thèse embrasse l'utilisation de modèles et d'analyses différentielles linéaires en raison de son élégante interprétation basée sur la fréquence. À cet égard, les propriétés de stabilité de ces systèmes sont régies par leur équation caractéristique, qui pour les systèmes à retards sont des quasi-polynômes. Ainsi, cette thèse étudie le comportement des racines de ces fonctions par rapport aux variations de leurs paramètres (coefficients du système et valeurs de retard) à travers des racines bien connues croisant la stabilité. Des méthodes numériques et des observations analytiques sont développées dans ce sens. En particulier, nous étudions les applications, les convertisseurs cc/cc, le pendule de Furuta, les dispositifs haptiques, et le problème MPPT-PV (maximum power point tracking - photovoltaic). Grâce à l'utilisation des régulateurs proportionnel-retard, proportionnel- dérivé basé sur retard, proportionnel-intégral retardé et proportionnel-retard-intégral. Nous proposons également une solution au problème classique de contrôle basé sur le retard, qui consiste à stabiliser une chaîne d'un nombre quelconque d'oscillateurs en appliquant un seul bloc de retard.

This thesis studies the use of delay-based controllers for dynamical systems. Applications, experimentation, and theoretical problematics are addressed. The main focus of the study is the conception of delay-based controllers inspired by the well-known PID controllers. Also, and equally important, we study the design of such controllers. More precisely, we develop methods to find the proper choice of the controller's parameters assuring stability for different types of controllers. To this end, the thesis embraces the use of linear differential models and analysis due to its elegant frequency-based interpretation. In this regard, the stability properties of these systems are governed by their characteristic equation, which for time-delay systems are the so-called quasi-polynomials or polynomials with constant coefficients. Thus, this thesis studies the behavior of the roots of these functions with respect to variations of their parameters (coefficients and time delay values) through well-known roots crossing stability. Numeric methods and analytical observations are developed in this sense. In particular, we study applications, dc/dc converters, the Furuta pendulum, haptic devices, and the MPPT-PV (maximum power point tracking - photovoltaic) problem. Through the use of the proportional-delayed, proportional-delay-based derivative, proportional-delayed integral, and proportional-delayed-integral controllers. Also, we propose a solution to the classical delay-based control problem of stabilizing a chain of any number of oscillators by applying a single delay block., Cette thèse étudie l'utilisation de contrôleurs basés sur le retard pour les systèmes dynamiques. Quelques applications, quelques expériences, ainsi que des problèmes et des solutions théoriques sont abordés. L'accent principal de l'étude est mis sur la conception de contrôleurs basés sur le retard inspirés des contrôleurs PID. Plus précisément, nous développons des méthodes pour trouver le bon choix des paramètres du contrôleur assurant la stabilité pour différents types de contrôleurs. À cette fin, la thèse embrasse l'utilisation de modèles et d'analyses différentielles linéaires en raison de son élégante interprétation basée sur la fréquence. À cet égard, les propriétés de stabilité de ces systèmes sont régies par leur équation caractéristique, qui pour les systèmes à retards sont des quasi-polynômes. Ainsi, cette thèse étudie le comportement des racines de ces fonctions par rapport aux variations de leurs paramètres (coefficients du système et valeurs de retard) à travers des racines bien connues croisant la stabilité. Des méthodes numériques et des observations analytiques sont développées dans ce sens. En particulier, nous étudions les applications, les convertisseurs cc/cc, le pendule de Furuta, les dispositifs haptiques, et le problème MPPT-PV (maximum power point tracking - photovoltaic). Grâce à l'utilisation des régulateurs proportionnel-retard, proportionnel- dérivé basé sur retard, proportionnel-intégral retardé et proportionnel-retard-intégral. Nous proposons également une solution au problème classique de contrôle basé sur le retard, qui consiste à stabiliser une chaîne d'un nombre quelconque d'oscillateurs en appliquant un seul bloc de retard.

Computational Fluid Dynamics simulation was used to study hydrothermal carbonization of avocado stone (AS) in a batch stirred reactor, using an open-loop controller system. The corresponding simulations were carried out in COMSOL Multiphysics 5.2. The different biomass-to-water ratio was investigated. The hydrodynamic study shows that the ideal stirring speed to obtain a homogeneous mixture inside the reactor is 550 rpm, due to the high density of AS particles (1547.64 ± 27.33 kg/m3). However, a stagnant zone was observed just below the impeller. To validate the CFD simulations temperature profiles with experimental data, the heat transfer coefficient of the insulator was determined (11.66 W/m2.K), this value was used to set the heat loss in the CFD simulation. According to the model, the difference between the thermal properties of biomass and water under hydrothermal carbonization conditions is negligible. However, experimentally, an increase in temperature was observed with increasing biomass to-water-ratio; this is due to the global hydrothermal carbonization of AS is exothermic reaction. The heat released during 8 h, including heat-up time, was −7.25 ± 0.32 MJ/kg of feedstock. Finally, a kinetic model was proposed taking into account the influence of temperature, heat-up time, reactor volume, and biomass concentration.

International audience

We consider a basic one-dimensional model which allows to obtain a diversity of diffusive regimes whose speed depends on the moments of a per-site trapping time. This models a discrete subordinated random walk, closely related to the continuous time random walks widely studied in the literature. The model we consider lends itself to a detailed elementary treatment, based on the study of recurrence relation for the time-[Formula: see text] dispersion of the process, making it possible to study deviations from normality due to finite time effects.

International audience; Vertically aligned multiwalled carbon nanotubes synthetized by catalytic chemical vapor deposition are irradiated with low kinetic energy oxygen ions to graft oxygen functional groups at their surface. Subsequently, the thermal stability of these functional groups is investigated by heating the sample progressively to 200, 300, 400 and 500 °C. X-Ray photoelectron spectroscopy (XPS) is used to analyze the atomic concentration and chemical configuration at the sample surface after each stage. Scanning and transmission electron microscopies are used to observe the morphology of the nanotubes after the thermal treatment. The solvent-free functionalization is carried out in 10 min reaching an oxygen atomic concentration of 17.2 at.%, with no impurities introduced. At the end of the thermal treatment, the relative oxygen content drops to 5.6 at.%. XPS analysis indicates that four oxygen groups produced by the ion irradiation: epoxide, hydroxyl, carbonyl, and carboxyl groups, with the epoxides being the least stable and the carbonyls the most stable. Combining low kinetic energy ion-irradiation with a post-thermal anneal is shown to be an effective route to simultaneously control both sample oxygen content and the ratio of different oxygenated functional groups.

International audience; Aims: Monocytes and macrophages express cell-surface markers indicative of their inflammatory and activation status. In this study, we investigated whether these markers are affected or correlated in non-obese T2D subjects, or glycemic/metabolic control variables. Methods: Clinical data was recorded, and peripheral blood drawn from T2D patients (n = 28) and control subjects (n = 27). Isolated monocytes were evaluated by flow cytometry for the expression of CD14, CD16, and the phenotypic markers for the different states of activation spectrum, such as pro-inflammatory (M1) (HLA-DR, CD86), antiinflammatory/pro-resolving (M2) (CD163, CD206, MERTK, PD-L1) and metabolically-activated (MMe) (CD36, ABCA-1). From a subset of individuals, monocytes-derived macrophages (MDM) were obtained and evaluated for phenotypic markers. A correlation analysis was performed between the clinical variables and the marker expression. Results: The frequency of CD14 ++ CD16 − monocytes was lower in T2D patients and it correlates negatively with poor control in glycemic and metabolic variables. T2D monocytes expressed lower levels of HLA-DR, CD86, PD-L1, and CD163, which correlated negatively with poor metabolic control. In MDM from T2D patients, HLA-DR, CD86 and CD163 expression was lower and it inversely correlated with deficient glycemic or metabolic control parameters. Conclusion: The glycemic/metabolic control associated with T2D influences monocyte and MDM phenotypes toward an immune-suppressive phenotype.

International audience; The results presented in this paper deal with the design of a current sensorless delay–based controller for the closed–loop stabilization of a photovoltaic system under an MPPT scheme using a boost dc/dc converter. Some applications of such topology are dc microgrids, solar vehicles, or stand-alone systems, to mention a few. The basis of this control scheme relies on the feedback linearization control technique coupled with a delay–based low-order controller. In order to study the stability, the proposed approach uses a geometric point of view which allows the partitioning of the controller parameters space into regions with similar stability characteristics (same number of unstable characteristic roots). The most important contribution of the paper relies on providing practical guidelines to tune the gains of the proposed delay–based controller, ensuring asymptotic stability of the closed–loop system and fulfilling the requirements for photovoltaic applications. In addition, the proposed approach allows the design a non-fragile controller with respect to the controller gains. Furthermore, in order to test the effectiveness of the control scheme presented, experimental results evaluating the closed–loop system performance under set-point changes and abrupt irradiance disturbances are addressed using a solar array simulator and a battery bank as load.

International audience; Nowadays, an adequate design of wastewater treatment plants taking into consideration ail sustainability dimensions- economic, environmental and social- is fundamental. This can be achieved by implementing systematic methodologies where conceptual and mathematical tools can be used together. This contribu­tion proposes a framework that uses total cost, consumed energy, and reclaimed wastewater as sustain­ability metrics. A mixed-integer nonlinear programming problem arises from a general superstructure for wastewater treatment plants. A case study from Mexico City is solved by a hybrid multiobjective opti­mization approach that combines lexicographie and e-constraint methods. Solutions are provided in the form of a Pareto front. A modified technique for order of preference by similarity to ideal solution (M­TOPSIS) analysis is used as a multiple criteria decision-making tool to find the best trade-off solution. The optimal sustainable configuration resulted consists of three levels of treatment and 100% of treated water reuse.

The local current flow through three small aromatic carbon molecules, namely benzene, naphthalene and anthracene, is studied. Applying density functional theory and the non-equilibrium Green’s function method for transport, we demonstrate that pronounced current vortices exist at certain electron energies for these molecules. The intensity of these circular currents, which appear not only at the anti-resonances of the transmission but also in vicinity of its maxima, can exceed the total current flowing through the molecular junction and generate considerable magnetic fields. The π electron system of the molecular junctions is emulated experimentally by a network of macroscopic microwave resonators. The local current flows in these experiments confirm the existence of current vortices as a robust property of ring structures. The circular currents can be understood in terms of a simple nearest-neighbor tight-binding Hückel model. Current vortices are caused by the interplay of the complex eigenstates of the open system which have energies close-by the considered electron energy. Degeneracies, as observed in benzene and anthracene, can thus generate strong circular currents, but also non-degenerate systems like naphthalene exhibit current vortices. Small imperfections and perturbations can couple otherwise uncoupled states and induce circular currents.

International audience; This paper addresses the classification of multiple critical roots of dynamical continuous linear time-invariant systems including two constant delays in their mathematical representation. By considering the associated Weierstrass polynomial and its algebraic properties, we investigate the splitting behavior of such critical roots when the delays are subject to small variations. Some degenerate cases are also considered. The effectiveness of the proposed approach is illustrated through several numerical examples.

International audience; In this paper, the stability of a class of marginally stable SISO systems is studied by applying one delay block as a feedback controller. More precisely, we consider an open-loop system with no zeros and whose poles are located exactly on the imaginary axis. Furthermore, a control law formed uniquely by a proportional gain and a delayed behavior is proposed for its closed-loop stabilization. The main ideas are based on a detailed analysis of the characteristic quasi-polynomial of the closed-loop system as the controller parameters (gain, delay) are varied. More precisely, by using the Mikhailov stability criterion, for a fixed delay value, we compute some gain margin guaranteeing the closed-loop stability. The particular case when the characteristic roots of the open-loop system are equidistantly distributed on the imaginary axis is also addressed. Finally, an illustrative example shows the effectiveness of the approach.

International audience

Background Obesity is a major public health concern worldwide. A sedentary life and a nutritional transition to processed foods and high-calorie diets are contributing factors to obesity. The demand for nutraceutical foods, such as herbal weight-loss products, which offer the potential to counteract obesity, has consequently increased. We hypothesised that Opuntia cladodes consumption could assist weight management in an obesity prevention context. Methods This study was designed to explore the anti-adipogenic effects of lyophilised Opuntia cladode powders (OCP) in an in vitro cellular model for adipocyte differentiation and an in vivo high-fat-diet (HFD)-induced obesity rat model. Two OCP were tested, one from wild species O. streptacantha and the second from the most known species O. ficus-indica. Results Pre-adipocytes 3 T3-F442A were treated by OCP during the differentiation process by insulin. OCP treatment impaired the differentiation in adipocytes, as supported by the decreased triglyceride content and a low glucose uptake, which remained comparable to that observed in undifferentiated controls, suggesting that an anti-adipogenic effect was exerted by OCP. Sprague–Dawley rats were fed with a normal or HFD, supplemented or not with OCP for 8 weeks. OCP treatment slightly reduced body weight gain, liver and abdominal fat weights, improved some obesity-related metabolic parameters and increased triglyceride excretion in the faeces. Taken together, these results showed that OCP might contribute to reduce adipogenesis and fat storage in a HFD context, notably by promoting the faecal excretion of fats. Conclusions Opuntia cladodes may be used as a dietary supplement or potential therapeutic agent in diet-based therapies for weight management to prevent obesity. Graphical abstract

We consider equilibrium states (that is, shift-invariant Gibbs measures) on the configuration space $S^{\mathbb{Z}^d}$ where $d\geq 1$ and $S$ is a finite set. We prove that if an equilibrium state for a shift-invariant uniformly summable potential satisfies a Gaussian concentration bound, then it is unique. Equivalently, if there exist several equilibrium states for a potential, none of them can satisfy such a bound., Comment: 24 pages. Accepted for publication in J. Stat. Phys. (2020). Some typos have been corrected. Proposition 2.2 has been strengthened: if a Gaussian concentration bound holds then the measure is mixing, not only ergodic

Metagenomic sequencing has greatly improved our ability to profile the composition of environmental and host-associated microbial communities. However, the dependency of most methods on reference genomes, which are currently unavailable for a substantial fraction of microbial species, introduces estimation biases. We present an updated and functionally extended tool based on universal (i.e., reference-independent), phylogenetic marker gene (MG)-based operational taxonomic units (mOTUs) enabling the profiling of >7700 microbial species. As more than 30% of them could not previously be quantified at this taxonomic resolution, relative abundance estimates based on mOTUs are more accurate compared to other methods. As a new feature, we show that mOTUs, which are based on essential housekeeping genes, are demonstrably well-suited for quantification of basal transcriptional activity of community members. Furthermore, single nucleotide variation profiles estimated using mOTUs reflect those from whole genomes, which allows for comparing microbial strain populations (e.g., across different human body sites)., Nature Communications, 10 (1), ISSN:2041-1723

International audience; Vertically aligned multiwalled carbon nanotubes (v-CNTs) were functionalized with oxygen groups using low kinetic energy oxygen ion irradiation. X-ray photoelectron spectroscopy (XPS) analysis indicates that oxygen ion irradiation produces three different types of oxygen functional groups at the CNTs surface: epoxide, carbonyl and carboxyl groups. The relative concentration of these groups depends on the parameters used for oxygen ion irradiation. Scanning electron microscopy (SEM) shows that the macroscopic structure and alignment of v-CNTS are not affected by the ion irradiation and transmission electron microscopy (TEM) proves tip functionalization of v-CNTs. We observed that in comparison to oxygen plasma treatment, oxygen ion irradiation shows higher functionalization efficiency and versatility. Ion irradiation leads to higher amount of oxygen grafting at the v-CNTs surface, besides different functional groups and their relative concentration can be tuned varying the irradiation parameters.

International audience; In this paper, the influence of etching depth on the dark current and photo-response of a mid-wave infrared Ga-free T2SL XBn pixel detector is investigated. Two wet chemical etching depths have been considered for the fabrication of a non-passivated individual pixel detector having a cut-off wavelength of 5 µm at 150 K. This study shows the strong influence of the lateral diffusion length of a shallow-etched pixel on the electro-optical properties of the device. The lowest dark current density was recorded for the deep-etched detector, on the order of 1 × 10−5 A/cm2 at 150 K and a bias operation equal to −400 mV. The corresponding quantum efficiency was measured at 60% (without anti-reflection coating) for a 3 µm thick absorbing layer. A comparison of experimental results obtained on the two kinds of etched pixels demonstrates the need for a deep-etching process combined with efficient passivation for FPA manufacturing.

The work reported here demonstrates that it is possible to accurately determine surface gravities of $\delta$ Sct stars using the frequency content from high precision photometry and a measurement of the parallax. Using a sample of 10 eclipsing binary systems with a $\delta$ Sct component and the unique $\delta$ Sct star discovered with a transiting planet, WASP-33, we were able to refine the $\Delta\nu-\bar\rho$ relation. Using this relation and parallaxes, we obtained independent values for the masses and radii, allowing us to calculate the surface gravities without any constraints from spectroscopic or binary analysis. A remarkably good agreement was found between our results and those published, extracted from the analysis of the radial velocities and light curves of the systems. This reinforces the potential of $\Delta\nu$ as a valuable observable for $\delta$ Sct stars and settles the degeneracy problem for the $\log g$ determination through spectroscopy., Comment: 5 pages, 2 figures, 1 table

National audience; Le module interactif « Les réacteurs polyphasiques » permet de : comprendre les processus couplés de transfert et de réactions, observés dans les réactions hétérogènes ; décrire et modéliser ces phénomènes, à partir de grandeurs mesurables ; choisir et dimensionner des réacteurs, pour la mise en œuvre de ces réactions hétérogènes.La première partie permet de revoir ou d'aborder les notions nécessaires pour appréhender les réactions et réacteurs polyphasiques : milieux poreux et granulaires ; catalyse ; phénomènes de transfert ; réacteurs idéaux ; bilans. Les trois parties suivantes concernent chacune un type de réactions et réacteurs hétérogènes (à solide consommable ; à catalyseur solide ; gaz/liquide), avec à chaque fois une partie détaillant les phénomènes à l'échelle de la réaction, puis la présentation des différents types de réacteurs et la modélisation de certains d'entre eux.Ce module comporte : une vidéo animée « 5 min pour comprendre : le réacteur piston », un jeu sérieux « à la dérive », un TP immersif sur la mesure de kL.a, des quiz et des exercices. Il est illustré par différents schémas, graphiques ou dessins et par de nombreuses vidéos. Il propose également une nomenclature interactive, un glossaire et une liste des références bibliographiques majeures.L’objet de ce poster est de présenter le module et toutes ses composantes, mais aussi le déroulement de ce projet collaboratif (avec les difficultés rencontrées et les retours d’expérience avec les élèves) et enfin les perspectives pour des travaux futurs.Remerciements : Jérôme DUPIRE, Christophe LE NOUAIL, Stéphanie MADER et Guillaume VATAN (le Cnam) ; Henri DELMAS, Franck DUNGLAS, Carine JULCOUR et Hugues VERGNES (Ensiacet) ; Veronica AVALOS ROBERTTI (Université Pierre et Marie Curie)Prestataires : Loïc ALEJANDRO (Odigi) ; Gaël BOURHIS, Simon CHAUVIN et Romain ENSELME (Le Chant du cygne) ; Gabriela GARCIA COVA (traductrice espagnol)

International audience; In this chapter, the analysis of the behavior of multiple critical roots with respect to the delay parameters for a class of quasi-polynomials is addressed. The analysis is based on the construction of the so-called Weierstrass polynomial. Several numerical examples encountered in the control literature are considered to illustrate the proposed approach.

International audience; This paper focuses on the design of two different delay-based control schemes. These two low-complexity controllers are proposed as alternatives for the classical PD and PI controllers. More precisely, first, we study a PD controller using the Euler approach for approximating the derivative action. Second, we analyze the implications of imposing a delay in the error signal on the integral action of the PI controller for closed-loop response manipulation purposes. Our main contribution lies in proposing some practical guidelines for the tuning of these delayed control schemes such that the closed-loop system is stable. To this end, the criteria developed in this work makes use of the well-known D—partition method, with the difference that we propose a simple criterion to detect stabilizing regions, avoiding in this way the crossing direction analysis. Several numerical examples illustrate the effectiveness of the proposed approach.

Today, surface acoustic waves (SAWs) and bulk acoustic waves are already two of the very few phononic technologies of industrial relevance and can been found in a myriad of devices employing these nanoscale earthquakes on a chip. Acoustic radio frequency filters, for instance, are integral parts of wireless devices. SAWs in particular find applications in life sciences and microfluidics for sensing and mixing of tiny amounts of liquids. In addition to this continuously growing number of applications, SAWs are ideally suited to probe and control elementary excitations in condensed matter at the limit of single quantum excitations. Even collective excitations, classical or quantum are nowadays coherently interfaced by SAWs. This wide, highly diverse, interdisciplinary and continuously expanding spectrum literally unites advanced sensing and manipulation applications. Remarkably, SAW technology is inherently multiscale and spans from single atomic or nanoscopic units up even to the millimeter scale. The aim of this Roadmap is to present a snapshot of the present state of surface acoustic wave science and technology in 2019 and provide an opinion on the challenges and opportunities that the future holds from a group of renown experts, covering the interdisciplinary key areas, ranging from fundamental quantum effects to practical applications of acoustic devices in life science.

Human Parainfluenza viruses (HPIV) type 1 and 3 are important causes of respiratory tract infections in young children globally. HPIV infections do not confer complete protective immunity so reinfections occur throughout life. Since no effective vaccine is available for the two virus subtypes, comprehensive understanding of HPIV-1 and HPIV-3 genetic and epidemic features is important for diagnosis, prevention, and treatment of HPIV-1 and HPIV-3 infections. Relatively few whole genome sequences are available for both HPIV-1 and HPIV-3 viruses, so our study sought to provide whole genome sequences from multiple countries to further the understanding of the global diversity of HPIV at a whole-genome level. We collected HPIV-1 and HPIV-3 samples and isolates from Argentina, Australia, France, Mexico, South Africa, Switzerland, and USA from the years 2003-2011 and sequenced the genomes of 40 HPIV-1 and 75 HPIV-3 viruses with Sanger and next-generation sequencing with the Ion Torrent, Illumina, and 454 platforms. Phylogenetic analysis showed that the HPIV-1 genome is evolving at an estimated rate of 4.97 × 10-4 mutations/site/year (95% highest posterior density 4.55 × 10-4 to 5.38 × 10-4) and the HPIV-3 genome is evolving at a similar rate (3.59 × 10-4 mutations/site/year, 95% highest posterior density 3.26 × 10-4 to 3.94 × 10-4). There were multiple genetically distinct lineages of both HPIV-1 and 3 circulating on a global scale. Further surveillance and whole-genome sequencing are greatly needed to better understand the spatial dynamics of these important respiratory viruses in humans.

International audience; This paper focuses on the design of a P-δ I controller for the stabilization of a buck dc/dc converter. The basis of this work is a geometric approach which allows to partition the parameters space of the controllers gain into regions in which the characteristic equation of the closed-loop system has a constant number of unstable roots. The main contribution of the paper is that it provides an explicit tool to find P-δ I gains ensuring the stability of the closed-loop system. In addition, the proposed methodology allows the design of a controller with a desired exponential decay rate σ. In order to illustrate the effectiveness of the proposed controller, several numerical examples are presented. © 2019 IEEE.

The present work deals with a consensus control for a multi-agent system composed by a mini Vertical Take-off and Landing (VTOL) rotorcrafts by means of a controller based on time-delay parametrization. The VTOL system modeling is presented using the quaternion parametrization to develop the attitude-stabilizing law of the aerial robots. The vehicle position dynamics are extended to the multi-agent case where a time-delayed PID control is designed in order to achieve general consensus in terms of formation control of the system. Finally, a detailed simulation study is presented to validate the effectiveness of the proposed control strategy, where it also considered a collective interaction.

The actual paper provides a detailed comparative study of two rotorcraft configurations in terms of their stability with time-delay in the control loop of the system. These configurations correspond to the tilt-rotor (fully-actuated) and fixed-rotor (underactuated) rotorcraft. Such analysis considers the coupling between translation (slow dynamics) and rotational (fast dynamics) motions as a delayed system. Thus, a set of stability charts are presented to illustrate the stability profile for each configuration. We have carried out numerical models that captures essential dynamics of such aerial robots.

The main goal of this paper is to introduce a new non-holonomic model and control of a tilt-rotor aerial robot for interactive operations via a 1DOF robotic manipulator. The modeling is derived by means of the Euler-Lagrange formulation, providing couplings between the robotic manipulator and the rotorcraft. The aerial robot is fully actuated and features thrust vector control, having a more flexible aerial profile. In terms of control, the Immersion and Invariance (I&I) control technique is applied in order to achieve the control objective (trajectory tracking). Finally, preliminary simulation results were conducted to evaluate and validate the control strategy for an interactive tilt-rotor micro aerial vehicle (MAV).

A series of activated carbons (ACs) were prepared by modifying a commercial AC by physical activation using CO2 during different activation times. The ACs were designated as F, F12, F24, and F40 corresponding to the activation times of 0, 12, 24, and 40 h, respectively. The surface area, total pore volume, micropore volume, and mean micropore width were determined for all the ACs. The textural properties of the modified ACs increased substantially with the activation time, and the capacity of the ACs for adsorbing diclofenac (DCF) was almost linearly dependent upon the surface area of the ACS. The maximum adsorption capacities of F, F12, F24, and F40 carbons towards diclofenac (DCF) from aqueous solution were 271, 522, 821, and 1033 mg/g, respectively. Hence, the adsorption capacities of ACs were considerably enhanced with the activation time, and F12, F24, and F40 carbons presented the highest adsorption capacities towards DCF reported in the technical literature. The F40 adsorption capacity was at least twice those of other carbon materials. The adsorption capacities decreased by raising the pH from 7 to 11 due to electrostatic repulsion between the ACs surface and anionic DCF in solution. The removal of DCF from a wastewater treatment plant (WWTP) effluent was effectively carried out by adsorption on F40. Hence, the capacity of ACs for adsorbing DCF can be optimized by tailoring the porous structure of ACs., This work was supported by Consejo Nacional de Ciencia y Tecnologia, CONACyT, Mexico (grants numbers INFR-2012-01-188381 and CB-2012-02-182779). COA and JBP thank the support of the Spanish MINECO (grant number CTM2014/56770-R).

This paper focuses on the analysis of the behavior of characteristic roots of time-delay systems, when the delay is subject to small parameter variations. The analysis is performed by means of the ...

This article is contribution number 94 of Tara Oceans.-- 37 pages, 20 figures, 1 table, supplementary information https://doi.org/10.1016/j.cell.2019.10.014.-- All raw reads are available through ENA at https://www.ebi.ac.uk/ena using the identifiers listed in https://doi.org/10.5281/zenodo.3473199. Processed data are accessible at https://www.ebi.ac.uk/biostudies/studies/S-BSST297, and additional information is provided in https://doi.org/10.5281/zenodo.3473199 and at the companion website: https://www.ocean-microbiome.org. Scripts used in this manuscript are available through a Github repository at https://github.com/SushiLab/omrgc_v2_scripts, Ocean microbial communities strongly influence the biogeochemistry, food webs, and climate of our planet. Despite recent advances in understanding their taxonomic and genomic compositions, little is known about how their transcriptomes vary globally. Here, we present a dataset of 187 metatranscriptomes and 370 metagenomes from 126 globally distributed sampling stations and establish a resource of 47 million genes to study community-level transcriptomes across depth layers from pole-to-pole. We examine gene expression changes and community turnover as the underlying mechanisms shaping community transcriptomes along these axes of environmental variation and show how their individual contributions differ for multiple biogeochemically relevant processes. Furthermore, we find the relative contribution of gene expression changes to be significantly lower in polar than in non-polar waters and hypothesize that in polar regions, alterations in community activity in response to ocean warming will be driven more strongly by changes in organismal composition than by gene regulatory mechanisms, Tara Oceans (that includes both the Tara Oceans and Tara Oceans Polar Circle expeditions) would not exist without the leadership of the Tara Expeditions Foundation and the continuous support of 23 institutes (https://oceans.taraexpeditions.org). We further thank the commitment of the following sponsors: CNRS (in particular Groupement de Recherche GDR3280 and the Research Federation for the study of Global Ocean Systems Ecology and Evolution, FR2022/Tara Oceans-GOSEE); European Molecular Biology Laboratory (EMBL); Genoscope/CEA; the French Ministry of Research; the French Government “Investissements d’Avenir” programmes OCEANOMICS (ANR-11-BTBR-0008), FRANCE GENOMIQUE (ANR-10-INBS-09-08), MEMO LIFE (ANR-10-LABX-54), and PSL∗ Research University (ANR-11-IDEX-0001-02); Gordon and Betty Moore Foundation (award 3790); the US National Science Foundation (OCE#1536989 and OCE#1829831 to M.B.S.); the European Union’s Horizon 2020 research and innovation programme (grant agreement 686070); and the Ohio Supercomputer and the EMBL and ETH Zürich HPC facilities for computational support. Funding for the collection and processing of the TARA data set was provided by NASA Ocean Biology and Biogeochemistry program under grants NNX11AQ14G, NNX09AU43G, NNX13AE58G, and NNX15AC08G to the University of Maine and Canada Excellence Research Chair on Remote sensing of Canada’s new Arctic frontier Canada Foundation for Innovation. C.B. acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement 835067). S.G.A. thanks the Spanish Ministry of Economy and Competitiveness (CTM2017-87736-R). S. Sunagawa. is supported by the ETH and the Helmut Horten Foundation and by funding from the Swiss National Foundation (205321_184955)

The use of nanoparticles, in combination with ionizing radiation, is considered a promising method to improve the performance of radiation therapies. In this work, we engineered mono- and bimetallic core-shell gold–platinum nanoparticles (NPs) grafted with poly (ethylene glycol) (PEG). Their radio-enhancing properties were investigated using plasmids as bio-nanomolecular probes and gamma radiation. We found that the presence of bimetallic Au:Pt-PEG NPs increased by 90% the induction of double-strand breaks, the signature of nanosize biodamage, and the most difficult cell lesion to repair. The radio-enhancement of Au:Pt-PEG NPs were found three times higher than that of Au-PEG NPs. This effect was scavenged by 80% in the presence of dimethyl sulfoxide, demonstrating the major role of hydroxyl radicals in the damage induction. Geant4-DNA Monte Carlo simulations were used to elucidate the physical processes involved in the radio-enhancement. We predicted enhancement factors of 40% and 45% for the induction of nanosize damage, respectively, for mono- and bimetallic nanoparticles, which is attributed to secondary electron impact processes. This work contributed to a better understanding of the interplay between energy deposition and the induction of nanosize biomolecular damage, being Monte Carlo simulations a simple method to guide the synthesis of new radio-enhancing agents., This work was jointly supported by the European Union Seventh Framework Program (PEOPLE-2013 ITN-ARGENT Marie Curie project), under grant agreement no. 608163, and the Spanish Ministerio de Economía y Competitividad, project no. FIS2016-80440. Authors express their gratitude to the Mexican National Council for Science and Technology (CONACyT) for supporting the work of Daniela Salado-Leza through the Ph.D. CONACyT–Gobierno Francés scholarship 216823/312283.

International audience; We present superfactorial and exponential lower bounds on the number of Hamiltonian cycles passing through any edge of the basis graph of generalized Catalan, uniform, and graphic matroids. All lower bounds were obtained by a common general strategy based on counting appropriated cycles of length four in the corresponding matroid basis graph.

International audience; This paper proposes an analytical method to characterize the behavior of multiple critical roots of a retarded system with two delays. Expressing locally the related characteristic function, as a Weierstrass polynomial, we derive several results to analyze the stability behavior of such characteristic roots with respect to small variations on the delay parameters. The proposed results are illustrated by considering several numerical examples.

This paper proposes an analytical method to characterize the behavior of critical multiple roots for quasi-polynomials with two delays. The proposed approach is based on the Weierstrass polynomial, that is employed as a tool to analyze the stability behavior of such characteristic roots with respect to small variations on the delay parameters. A numerical example illustrates the proposed results.

Environmental mercury (Hg) contamination is an urgent global health threat. The complexity of Hg in the environment can hinder accurate determination of ecological and human health risks, particularly within the context of the rapid global changes that are altering many ecological processes, socioeconomic patterns, and other factors like infectious disease incidence, which can affect Hg exposures and health outcomes. However, the success of global Hg-reduction efforts depends on accurate assessments of their effectiveness in reducing health risks. In this paper, we examine the role that key extrinsic and intrinsic drivers play on several aspects of Hg risk to humans and organisms in the environment. We do so within three key domains of ecological and human health risk. First, we examine how extrinsic global change drivers influence pathways of Hg bioaccumulation and biomagnification through food webs. Next, we describe how extrinsic socioeconomic drivers at a global scale, and intrinsic individual-level drivers, influence human Hg exposure. Finally, we address how the adverse health effects of Hg in humans and wildlife are modulated by a range of extrinsic and intrinsic drivers within the context of rapid global change. Incorporating components of these three domains into research and monitoring will facilitate a more holistic understanding of how ecological and societal drivers interact to influence Hg health risks. Dartmouth College Toxic Metals Superfund Research Program through National Institute of Environmental Health [R13 ES028077-01, P42ES007373]; USGS Environmental Health Mission Area, Contaminant Biology Program; IUF (Institut Universitaire de France) The paper was written as part of the synthesis effort for the 13th International Conference on Mercury as a Global Pollutant, Providence, Rhode Island, July 16-21, 2017. It was supported by Dartmouth College Toxic Metals Superfund Research Program through funds from the National Institute of Environmental Health under Award Number R13 ES028077-01 and Award Number P42ES007373. Funding was also provided by the USGS Environmental Health Mission Area, Contaminant Biology Program. The IUF (Institut Universitaire de France) is thanked for its support to PB. We appreciate the technical comments and supports of Celia Chen and Charley Driscoll, and the insightful comments and editing of Stacey Tobin and two anonymous reviewers. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Public domain – authored by a U.S. government employee