Gustave Eiffel University

Our research challenges the prevailing notion that immobility only occurs in exceptional circumstances. Our work shows instead a close link with individuals’ activity levels and constraints on their schedules. We find that retirees exhibit higher immobility levels than workers, influenced by factors such as poor health, old age, low income, lack of access to a car, or rural residency. Analyzing data from last French National Transport Survey, we use structural equation models to examine the impact of various factors on immobility. Driving and walking difficulties are significant contributors to immobility, with age being a primary explanatory factor. However, living in dense urban areas tends to reduce immobility levels across household categories. Difficulties with public transport, as such, do not trigger immobility, but they are entangled with walking difficulties. Implications for public action include targeting vulnerable populations, considering age-specific interventions for reducing car dependency, and approaching policies aimed at curbing older adults’ car use cautiously. Implementing universal design measures to enhance physical accessibility also helps to make mobility smoother and decrease perceived walking difficulties. Finally, this paper underlines the entanglement of mobility and social isolation, emphasizing the need for qualitative and quantitative research in this area.

The need for highly integrated system design for Analog Radio over Fiber (ARoF) architecture has long been identified as a solution to improve its noise figure and dynamic range. While silicon photonics has been the major technology driving this solution with several demonstrations of integrated filters, photodiodes, and amplifiers, etc., effective laser integration with silicon photonics has only recently found a way out through heterogeneous integration of III-V materials on Silicon (III-V/Si) substrate. With the laser integration access on this technology, an optimised design is needed to ensure its compliance with sensitive applications such as ARoF in both static and dynamic behaviours. In view of this, the path to better performance of heterogeneous III-V/Si laser through integrated extended cavity and enhanced optical mode confinement factor are highlighted in this paper. Four laser chips are characterized and compared to study how differences in confinement factor and extended cavity configuration could influence the output power, wavelength tunability and Relative Intensity Noise (RIN). Two different configurations of integrated extended cavities, achieved with Sagnac mirrors and micro-ring resonators based Vernier filter, are presented and the confinement factor variation was achieved by changing the Si waveguide width. The presented measurement results show that a small integrated laser diode with an output power of $\sim \rm{5}~\rm{mW}$ and tunable wavelength range up to $\rm{48}~\rm{nm}$ , has reduced RIN property below $-140~dB/Hz$ which is a key performance index for ARoF applications.

Entropy comparison inequalities are obtained for the differential entropy h ( X + Y ) of the sum of two independent random vectors X , Y , when one is replaced by a Gaussian. For identically distributed random vectors X , Y , these are closely related to bounds on the entropic doubling constant, which quantifies the entropy increase when adding an independent copy of a random vector to itself. Consequences of both large and small doubling are explored. For the former, lower bounds are deduced on the entropy increase when adding an independent Gaussian, while for the latter, a qualitative stability result for the entropy power inequality is obtained. In the more general case of non-identically distributed random vectors X , Y , a Gaussian comparison inequality with interesting implications for channel coding is established: For additive-noise channels with a power constraint, Gaussian codebooks come within a snr/3snr+2 factor of capacity. In the low-SNR regime this improves the half-a-bit additive bound of Zamir and Erez (2004). Analogous results are obtained for additive-noise multiple access channels, and for linear, additive-noise MIMO channels.

Calibration transfer techniques aim to standardize secondary instruments to a primary instrument, enabling the utilization of the primary instrument’s calibration model with minimal additional experiments. While widely employed in spectroscopic datasets, their application in environmental sensors and sensor arrays is less common despite the pressing need due to issues like sensor batch variability and time drift. This study assesses 10 calibration transfer techniques on three experimental gas sensor datasets that have a small number of transfer standards. Model-based (linear regression) and model-free (K-nearest-neighbour) calibration methods are also compared. Results unexpectedly show that, despite the reduced data availability, direct recalibration of the secondary sensor (eg. without transfer) may be sufficient for the secondary sensor to reach the same performance as the primary one. In the other cases, Partial-Least-Square Standardization and Direct Standardization are the most robust transfer methods across the use cases, and they can outperform direct recalibration. Other methods, such as Single Sensor Standardization, Mean Correction, Principal Component Standardization, and Procrustes Transform, have consistently lower performance in this small data context.

This second segment of a two-part study investigates the numerical modeling of the Navier slip boundary condition at the contact line at the junction of free and solid surfaces, a key element in many natural and technological processes. The first segment introduced a method based on the cut-cell formalism. This second segment demonstrates how this simple formulation can be used to flexibly mix Navier, no-slip and free-surface boundary conditions near sharp interfaces described using a levelset representation. The study emphasizes a unified treatment of boundaries and interfaces that retains the simplicity of the original methodology without requiring further simplifying assumptions. To that end, a two-levelset approach is employed, with one levelset defining the solid wall and the other defining the free-surface. The spreading of a droplet over straight and circular walls for different contact angles is used as validation cases. The expected first-order accuracy in mass loss/gain is achieved, with the maximum error in mass conservation reaching 10% in the worst-case scenario.

The VENoL analytical model was developed to reproduce the nonlinear viscoelastic behaviour of asphalt concrete in dynamic analysis. In this paper, it is integrated as a contact law in a 2D model using the Discrete Element Method. The asphalt concrete is modelled on a macroscopic scale. The VENoL model is applied in the numerical code without any recalibration of its analytical parameters. Particular attention is paid to modelling variations in the Poisson's ratio as a function of test conditions. This integration is checked by comparing the results of the numerical model with those extracted from the literature for complex modulus tests in direct tension-compression. Despite the use of a macroscopic scale, it appears that the model can reproduce porosity effects through the mechanisms of DEM. Using the same set of parameters, two-point bending tests are also conducted to ensure their compliance in the characterisation of bituminous mixes.

Bituminized waste products (BWPs) were produced by conditioning in bitumen the co‐precipitation sludge resulting from the industrial reprocessing of nuclear spent fuel. For some intermediate level long‐lived (ILW‐LL) classified BWPs, a long‐term disposal solution in France is underground geological disposal. One of the challenges for BWPs in geological disposal conditions is their swelling behavior due to water uptake. This swelling, if sufficiently important, could lead to mechanical coupling with the host rock, resulting in the application of pressure that could damage it. Consequently, the swelling behavior of BWPs must be considered in safety studies for the underground storage facility after site closure. The present work is a continuation of a previous one and focuses on investigating both experimentally and numerically the BWPs’ swelling behavior due to water uptake under confined leaching conditions. The swelling of simplified BWPs was experimentally monitored for about 2.5 years during leaching tests under constant counterpressure. The numerical model is extended from a previous work that incorporates coupled homogenization of transport terms (diffusion, permeation, osmosis) with mechanics via Maxwell's viscoelastic model. An original nonlinear poro‐viscoelastic model taking into account large strains is proposed in this paper to better model the BWPs leaching behavior under confined conditions. The experimental results of leaching tests under constant counterpressure are generally well predicted by the resulting numerical model. The role of the poorly soluble salts BaSO 4 within the solid BWP matrix is investigated.

This communication presents the results of four static load tests carried out on Soil-Cement columns realized using the wet Deep Mixing Method. After a short introduction, the geological and geotechnical context is presented, as well as the tool used to execute the columns. The instrumentation is then described into details. Then, the main results of the four load tests are presented, such as the bearing capacity and creep load. The base resistances and shaft resistances derived from the extensometers installed in the columns are then pared to each other. Finally, results are compared to past experiences realized in soils of comparable nature, and to calculated values according to different standards.

Studies have shown that adaptation to a virtual reality driving simulator takes time and that individuals differ widely in the time they need to adapt. The present study examined the relationship between attentional capacity and driving-simulator adaptation, with the hypothesis that individuals with better attentional capacity would exhibit more efficient adaptation to novel virtual driving circumstances. To this end, participants were asked to steer in a driving simulator through a series of 100 bends while keeping within a central demarcated zone. Adaptation was assessed from changes in steering behavior (steering performance: time spent within the zone, steering stability, steering reversal rate) over the course of the bends. Attentional capacity was assessed with two dynamic visual attention tasks (Multiple Object Tracking, MOT; Multiple Object Avoidance, MOA). Results showed effective adaptation to the simulator with repetition, as all steering-behavior variables improved. Both MOT and MOA scores significantly predicted adaptation, with MOT being a stronger predictor. Further analyses revealed that higher-capacity participants, but not their lower-capacity counterparts, produced more low-amplitude steering-wheel corrections early in the task, resulting in finer vehicle control and better performance later on. These findings provide new insights into adaptation to virtual reality simulators through the lens of attentional capacity. Supplementary Information The online version contains supplementary material available at 10.1038/s41598-024-79392-1.

This work reports the fabrication of p‐type Si micropillar (MP) substrates decorated with AgxCu100−x bimetallic nanoparticles and their application as photocathodes for CO2 photoelectrochemical reduction. Metal deposition by metal‐assisted chemical etching is chosen as the nanoparticle synthesis method, to explore for the first time its capabilities for 3D structures. It is found to be applicable, allowing a good control of the composition, with nanoparticles distributed along the entire MP, but with a coverage gradient from top to bottom. The AgxCu100−x decorated Si MPs photocathodes show enhanced light trapping compared to flat Si, with 45 % lower reflectance values in the visible and significantly higher catalytic activity, in terms of photocurrent density, overpotential and power savings (4.7 % for Ag50Cu50/Si MPs vs. 3 % for Ag50Cu50/flat‐Si). Si MPs coated with Ag50Cu50 and Ag20Cu80 provide the highest gain in potential (440 and 600 mV vs. bare Si MPs) and an increased selectivity towards high energy density products (i. e., CH4) compared to monometallic photocathodes. These are promising features for efficient light‐driven CO2 conversion. However, a significant metal loss is observed during photoelectrolysis, especially for Cu‐rich compositions. Suggestions to improve the photocathode performance in terms of metal coating homogeneity and catalyst stability are presented.

Objective Reporting the reinsertion of the triceps brachii onto the proximal ulna as a salvage procedure in a dog with nonreconstructible olecranon fracture. Case Description A Labrador Retriever was presented with a comminuted olecranon fracture. Initial fracture stabilization was unsuccessful, resulting in implant failure and a nonreconstructible comminuted fracture, thus preventing triceps tendon reattachment. Revision surgery was performed after the implants and bone fragments were removed. A synthetic implant was sutured onto the triceps tendon and fixed on the proximal ulna by an interference screw (IS) in a bone tunnel. A transarticular Jean-Alphonse Meynard external fixator was applied for 3 weeks. Results After 3 weeks, the dog had moderate lameness with a painless elbow. At 1.5 months, it had severe lameness with a painful elbow and mild osteoarthritis (OA). Nonsteroidal anti-inflammatory drugs were prescribed, and intensive physical therapy was initiated. Lameness improved at 2.5 and 3.5 months despite mild OA. At 9 months, the dog had mild lameness and a swelling of the elbow. Radiographs showed moderate OA and lucency around the IS. Bacteriologic examination was positive. The implants and infected tissues were removed, and antibiotics were prescribed for 1 month. At 18 months, the dog had mild lameness with no pain. At 33 months, it had intermittent mild lameness with no pain, yet severe OA. Conclusion Triceps tendon re-insertion onto the proximal ulna yielded satisfactory long-term outcome in this dog with nonreconstructible olecranon fracture.

Miniature and low‐cost light sources are highly desirable for numerous optical microsystems. Among these, devices based on blackbody radiation of a filament heated at a few hundred degrees, perfectly fit with the requirements of producing a broad spectral range falling in the infrared range, owing to Planck's law. These light sources are of primary interest for Fourier transform infrared (FTIR) spectroscopy. Although thermal light production is simple, achieving precise light intensity is not a trivial task. Herein, the impact of the inhomogeneous temperature on the emitted radiation is studied. Blackbody radiation formulae are revisited for miniature sources, taking into account the temperature distribution and using the principle of superposition of non‐coherent sources. A theoretical model is formulated by dividing the source into multiple annular elementary sources of different temperature. This results in effective, corrected blackbody emission. Analytical formulae are derived in the case of a quadratic temperature distribution. For the experimental validation, a silicon‐based source, made of a platinum resistive micro‐heater on top of heavily doped silicon, is fabricated and experimentally characterized at temperatures ranging from 300 to 520 K. The experimental results show good agreement with the model predictions in the explored wavelength range of (λ = 2.5–4.8 µm).

Recent theories of creative thinking propose that the generation of creative ideas by design novices and experts is restricted by the emergence of intuitive cognitive biases. To overcome these biases and explore expansive solutions, biased ideas must be discriminated from those with creative potential. Although studies in the field of reasoning have shown that biased participants tend to detect an incongruency between their provided solutions and the expected solution, the use of conflict detection in creativity has never been studied. Two experiments were conducted to determine the extent to which conflict detection occurs during creative idea generation and whether this mechanism is available for design novices (Experiment 1) and/or experts (Experiment 2). The results indicated that both groups of participants detected their fixation bias and managed to overcome it by switching from intuitive to deliberate thinking. In addition, we discussed implications for popular current (dual process) models.

Sonic Kinesthetic Forest is an interdisciplinary research project that explores novel methodologies for studying trees and forests through embodied sound, movement and drawing practices. Our video article reflects on this interdisciplinary research through the lens of a performance piece in which embodied sound, movement and drawing practices were intricately interwoven with a forest landscape. The process of developing this artistic work has strengthened our conviction that embodied interdisciplinary knowledge is urgently needed to support and bring new dimensions to the wide array of nature-based climate action initiatives happening around the world today.

The integration of Global Satellite Navigation System (GNSS) and Pedestrian Dead Reckoning (PDR) is one of the widely adopted solutions for smartphone-based pedestrian navigation. Due to the effects of multipath and Non-Line of Sight (NLOS) signals, low-cost GNSS chips embedded in smartphones face significant challenges in complex environments such as urban canyons, thereby threatening the availability of positioning information in integrated navigation systems. To address this problem, a GNSS/PDR integration navigation method enhanced by measurements resilient adjustment is proposed. Initially, an augmented GNSS/PDR model is established that leverages GNSS velocity to estimate step length, which serves as an additional GNSS measurement. Due to the poor measurement redundancy, GNSS measurements are then categorized and processed accordingly in the loosely-coupled model. For attaining position solutions, a resilient adjustment algorithm assisted by fault repair is proposed to correct GNSS measurements. For step length measurements, a step length test statistic is constructed, and anomalous step lengths estimated with GNSS are appropriately excluded. Experimental results demonstrate that the proposed method can effectively utilize GNSS observational data and perform targeted processing, thereby significantly enhancing the availability and continuity of positioning information in pedestrian navigation.

Marketing research targeting poor consumers has been developing recently. The specific characteristics of these consumers make it difficult to conduct empirical research. This difficulty has raised the question of how to adapt the methods and techniques usually used in marketing. This article provides a multidisciplinary review of the difficulties encountered in addressing people living in poverty and enables researchers to assess this population and anticipate their needs. In addition, based on a literature review of the methods used in 83 empirical marketing studies published between 1990 and 2021, our study provides researchers with a vade-mecum to guide them in their choice of research design. Concrete and detailed recommendations are provided to facilitate their involvement in the field of poor consumers.

Two‐dimensional analysis of tunnel design based on the convergence–confinement method, although commonly used in tunnel design, may not always be applied. For example, in squeezing grounds, if the support is installed very close to the tunnel face, three‐dimensional numerical modeling is required but is computationally expensive. Therefore, it is usually performed before or after tunnel excavation. A machine learning approach is presented here as an alternative to costly computations. Two surrogate models are developed based on synthetic data. The first model aims to assess the support pressure and the radial displacement at equilibrium in the lining and the radial displacement occurring close to the face at the installation distance of the support. The second model is intended to compute the extrusion of the core considering an unlined gallery. It is assumed a circular tunnel excavated in a Mohr–Coulomb elastoplastic perfectly plastic ground under an initial isotropic stress state. In particular, the bagging method is applied to neural networks to enhance the generalization capability of the models. A good performance is obtained using relatively scarce datasets. The modeling of the surrogate models is explained from the creation of the synthetic datasets to the evaluation of their performance. Their limitations are discussed. In practice, these two machine learning tools should be helpful in the field during the excavation phase.