Showing papers by "University of Rennes published in 2023"
TL;DR: In this article , the authors examine the sanctuary spaces and practices in the Roya Valley, at the border between Italy and France, and more particularly the journey of its most well-known activist, the farmer Cédric Herrou.
Abstract: Sanctuary cities have experienced a strong political and theoretical revival in the last decade. However, the focus on cities and their policies restricts the idea of sanctuary to its urban, legal and – to a certain extent – North American enactments, leaving dispersed and rural forms of sanctuary understudied. In this paper, I examine the sanctuary spaces and practices in the Roya Valley, at the border between Italy and France, and more particularly the journey of its most well-known activist, the farmer Cédric Herrou. Although Herrou’s first actions could be best described as humanitarian and hospitable help towards migrants, they gradually evolved into more structured solidarity actions. These led to a decision by the Constitutional Council that strengthened the French constitutional value of fraternity to better distinguish disinterested support from human smuggling motivated by profit. I argue that these three concepts of fraternity, hospitality and solidarity identify different repertoires of sanctuary that respectively fulfil functions of signalling, protecting and community-building. These different functions, when articulated together, constitute a sanctuary or network of safety. By reconstructing this series of practices and justifications, I aim to clarify the conceptual vocabulary and normative appeal of sanctuary.
5 citations
TL;DR: In this article , the size-dependent trion and biexciton binding energies of all-inorganic lead-halide perovskite (LHP) quantum dots were investigated.
Abstract: All-inorganic lead-halide perovskite (LHP) (CsPbX3, X = Cl, Br, I) quantum dots (QDs) have emerged as a competitive platform for classical light-emitting devices (in the weak light–matter interaction regime, e.g., LEDs and laser), as well as for devices exploiting strong light–matter interaction at room temperature. Many-body interactions and quantum correlations among photogenerated exciton complexes play an essential role, for example, by determining the laser threshold, the overall brightness of LEDs, and the single-photon purity in quantum light sources. Here, by combining cryogenic single-QD photoluminescence spectroscopy with configuration-interaction (CI) calculations, the size-dependent trion and biexciton binding energies are addressed. Trion binding energies increase from 7 to 17 meV for QD sizes decreasing from 30 to 9 nm, while the biexciton binding energies increase from 15 to 30 meV, respectively. CI calculations quantitatively corroborate the experimental results and suggest that the effective dielectric constant for biexcitons slightly deviates from the one of the single excitons, potentially as a result of coupling to the lattice in the multiexciton regime. The findings here provide a deep insight into the multiexciton properties in all-inorganic LHP QDs, essential for classical and quantum optoelectronic devices.
4 citations
TL;DR: In this article , the authors evaluated the effectiveness of percutaneous transcatheter PFO closure with Amplatzer™ (Abbott Laboratories, Abbott Park, IL, USA) devices, from a large single-center experience.
Abstract: Patent foramen ovale (PFO) has a high estimated prevalence (25% of the general population) and has been implicated in the pathogenesis of cryptogenic stroke and transient ischemic attack (TIA), as well as in the pathogenesis of migraine headache. This study evaluated the effectiveness of percutaneous transcatheter PFO closure with Amplatzer™ (Abbott Laboratories, Abbott Park, IL, USA) devices, from a large single-center experience.From January 1998 to December 2014, 577 patients (243 males and 334 females, mean age 50 years, range 11-82 years) with documented PFO and history of at least one episode of cryptogenic stroke/TIA (N.=356) or occasional finding of previous ischemic lesions on MRI (N.=221) underwent percutaneous transcatheter closure of PFO using an Amplatzer™ Occluder (Abbott Laboratories). All the procedures were performed under general anesthesia or mild sedation and were assisted by transesophageal or intracardiac echocardiography.Procedural success was 100%. After a median follow-up period of 2.7 years with echocardiographic evaluations, the rate of recurrent adverse cerebral events was 0.4%. Two patients (0.4%) required a secondary procedure for significant residual shunt. Of 36 patients with minor residual shunt, 30 (83%) showed spontaneous shunt regression at follow-up. There was a consistent decrease after procedure in headache migraine, platypnea-orthodeoxia, fainting episodes, syncope, and coenesthesia phenomena.Transcatheter PFO closure is an effective and safe therapy for the prevention of thromboembolic events in the patients with cryptogenic stroke/TIA or an occasional finding of a positive cerebral MRI. Late follow-up shows device stability and clinical improvement in the majority of patients.
2 citations
TL;DR: In this paper , the authors examined how sensitive the results of EEG analyses are to variations in preprocessing with different software tools and found that there is a good degree of convergence in terms of the general profile of EEG waveforms, peak latencies and effect size estimates related to specific signal features.
1 citations
TL;DR: In this paper , it was shown that it is possible to construct a Schnorr signature scheme on a module lattice, assuming the intractability of well-studied problems on lattice.
Abstract: Abstract The Fiat-Shamir with Aborts paradigm of Lyubashevsky has given rise to efficient lattice-based signature schemes. One popular implementation is Dilithium, which has been selected for standardization by the US National Institute of Standards and Technology (NIST). Informally, it can be seen as a lattice analog of the well-known discrete-logarithm-based Schnorr signature. An interesting research question is whether it is possible to combine several unrelated signatures, issued from different signing parties on different messages, into one single aggregated signature. Of course, its size should be significantly smaller than the trivial concatenation of all signatures. Ideally, the aggregation can be done offline by a third party, called public aggregation. Previous works have shown that it is possible to half-aggregate Schnorr signatures, but it was left open if the underlying techniques can be adapted to the lattice setting. In this work, we show that, indeed, we can use similar strategies to obtain a signature scheme allowing for public aggregation whose hardness is proven assuming the intractability of well-studied problems on module lattices. Unfortunately, our scheme produces aggregated signatures that are larger than the trivial solution of concatenating. This is due to peculiarities that seem inherent to lattice-based cryptography. Its motivation is thus mainly pedagogical.
TL;DR: In this paper , the authors explored the FM residents' perspectives about patient partner in teaching's participation in co-facilitated PEGs and how they changed over time, and showed the good acceptance of patient partners in teaching by FM residents in the context of PEG.
Abstract: The patient partner in teaching method is progressively developing for clinical training in France. Practice exchange groups (PEG) co-facilitated by patient partners in teaching are used during the training of family medicine (FM) residents. This study explored the FM residents' perspectives about patient partner in teaching's participation in co-facilitated PEGs and how they changed over time.In 2020, qualitative focus groups were carried out with 26 FM residents before and after a 5-month intervention based on monthly PEGs co-facilitated by patient partners in teaching. A reflective thematic analysis of the focus group interviews was performed according to Braun and Clarke's approach.FM residents supported patient partners in teaching's facilitation role and had high expectations concerning their contribution to the development of their skills and competencies. They expected patient partners in teaching to bring their individual experience and also a collective knowledge. Some limitations mentioned by FM residents disappeared over time, such as the loss of the medical group feeling among physicians, while others persisted and required pedagogical support targeted to FM residents before PEG initiation.This study shows the good acceptance of patient partners in teaching by FM residents in the context of PEGs. Attention should be paid to make FM residents aware of patient partners in teaching's missions before their introduction.
01 Jan 2023
01 Jan 2023
01 Jan 2023
TL;DR: In this article , the authors propose a model architecture that combines a predictor and a counterfactual generator that are jointly trained for regression or classification tasks, which is able to both generate predictions and to generate counter-factual explanations without having to solve another minimisation problem.
Abstract: Counterfactual explanation is a common class of methods to make local explanations of machine learning decisions. For a given instance, these methods aim to find the smallest modification of feature values that changes the predicted decision made by a machine learning model. One of the challenges of counterfactual explanation is the efficient generation of realistic counterfactuals. To address this challenge, we propose VCNet – Variational Counter Net – a model architecture that combines a predictor and a counterfactual generator that are jointly trained, for regression or classification tasks. VCNet is able to both generate predictions, and to generate counterfactual explanations without having to solve another minimisation problem. Our contribution is the generation of counterfactuals that are close to the distribution of the predicted class. This is done by learning a variational autoencoder conditionally to the output of the predictor in a join-training fashion. We present an empirical evaluation on tabular datasets and across several interpretability metrics. The results are competitive with the state-of-the-art method.
TL;DR: In this article , the characteristics and survival of patients transplanted for refractory electrical storm (ES) were evaluated in 11 French centers and the primary endpoint was in-hospital mortality.
Abstract: Abstract BACKGROUND Heart transplantation (HT) can be proposed as a therapeutic strategy for patients with severe refractory electrical storm (ES). Data in the literature are scarce and based on case reports. We aimed at determining the characteristics and survival of patients transplanted for refractory ES. METHODS Patients registered on HT waiting list during the following days after ES and eventually transplanted, from 2010 to 2021, were retrospectively included in 11 French centers. The primary endpoint was in-hospital mortality. RESULTS 45 patients were included (82% men; 55.0 (47.8-59.3) years old; 42.2% and 26.7% non-ischemic dilated or ischemic cardiomyopathies, respectively). Among them, 42 (93.3%) received amiodarone, 29 (64.4%) betablockers; 19 (42.2%) required deep sedation, 22 (48.9%) mechanical circulatory support, and 9 (20.0%) had radiofrequency catheter ablation. Twenty-two patients (62%) were in cardiogenic shock. Inscription on wait list and transplantation occurred 3.0 (1.0-5.0) days and 9.0 (4.0-14.0) days after ES onset, respectively. After transplantation, 20 patients (44.4%) needed immediate hemodynamic support by extracorporeal membrane oxygenation (ECMO). In-hospital mortality rate was 28.9%. Predictors of in-hospital mortality were serum creatinine/urea levels, need for immediate post-operative ECMO support, post-operative complications, and surgical re-interventions. One-year survival was 68.9%. CONCLUSION ES is a rare indication of HT but may be lifesaving in those patients presenting intractable arrhythmias despite usual care. Most patients can be safely discharged from hospital, although post-operative mortality remains substantial in this context of emergency transplantation. Larger studies are warranted to precisely determine those patients at higher risk of in-hospital mortality.
TL;DR: In this article , a correlation-based method for local diffusion estimation is proposed to analyze and estimate diffusion in local small areas at the scale of a single diffusing spot within cells.
Abstract: Abstract The dynamics and fusion of vesicles during the last steps of exocytosis are not well established yet in cell biology. An open issue is the characterization of the diffusion process at the plasma membrane. Total internal reflection fluorescence microscopy (TIRFM) has been successfully used to analyze the coordination of proteins involved in this mechanism. It enables to capture dynamics of proteins with high frame rate and reasonable signal-to-noise values. Nevertheless, methodological approaches that can analyze and estimate diffusion in local small areas at the scale of a single diffusing spot within cells, are still lacking. To address this issue, we propose a novel correlation-based method for local diffusion estimation. As a starting point, we consider Fick’s second law of diffusion that relates the diffusive flux to the gradient of the concentration. Then, we derive an explicit parametric model which is further fitted to time-correlation signals computed from regions of interest (ROI) containing individual spots. Our modeling and Bayesian estimation framework are well appropriate to represent isolated diffusion events and are robust to noise, ROI sizes, and localization of spots in ROIs. The performance of BayesTICS is shown on both synthetic and real TIRFM images depicting Transferrin Receptor proteins.
TL;DR: The first hydride-containing 2-electron palladium/copper alloys were synthesized from the reaction of trifluoroacetic acid (TFA) as discussed by the authors .
Abstract: The first hydride-containing 2-electron palladium/copper alloys, [PdHCu11{S2P(OiPr)2}6(C≡CPh)4] (PdHCu11) and [PdHCu12{S2P(OiPr)2}5{S2PO(OiPr)} (C≡CPh)4] (PdHCu12), are synthesized from the reaction of [PdH2Cu14{S2P(OiPr)2}6(C≡CPh)6] (PdH2Cu14) with trifluoroacetic acid (TFA). X-ray diffraction reveals that the PdHCu11 and PdHCu12 kernels consist of a central PdH unit encapsulated within a vertex-missing Cu11 cuboctahedron and complete Cu12 cuboctahedron, respectively. DFT calculations indicate that both PdHCu11 and PdHCu12 can be considered as axially-distorted 2-electron superatoms. PdHCu11 shows excellent HER activity, unprecedented within metal nanoclusters, with an onset potential of −0.05 V (at 10 mA cm−2), a Tafel slope of 40 mV dec−1, and consistent HER activity during 1000 cycles in 0.5 M H2SO4. Our study suggests that the accessible central Pd site is the key to HER activity and may provide guidelines for correlating catalyst structures and HER activity.
TL;DR: In this paper , it was shown that both of these methods can be generalized to the case of partial differential equations, this is, one can go either with the solution of tropicalized systems, or test monomial-freeness of the ideal generated by the initials when looking for supports of power series solutions of systems of differential equations.
TL;DR: In this article , the impact of the size of the nanohoop on the electronic and charge transport properties of [5]- and [4]-cyclo-N-butyl-2,7-carbazoles is reported.
Abstract: The impact of the hoop size on the electronic and charge transport properties of [5]- and [4]-cyclo-N-butyl-2,7-carbazoles is reported. In these examples, a small nanohoop is beneficial for good organization of the molecules into thin films, whereas a large one increases the density of structural defects. More information can be found in the Research Article by C. Poriel and co-workers (DOI: 10.1002/chem.202300934).
TL;DR: The PETRAW challenge as discussed by the authors included a data set of 150 peg transfer sequences performed on a virtual simulator, which described the workflow at three levels of granularity: phase, step, and activity.
TL;DR: In this paper , the authors characterize the countable groups of automorphisms of X for which the Koopman representation of X has a spectral gap and show that such groups can be characterized by a finite-dimensional, connected, compact abelian group.
Abstract: Abstract Let $S=\{p_1, \ldots , p_r,\infty \}$ for prime integers $p_1, \ldots , p_r.$ Let X be an S -adic compact nilmanifold, equipped with the unique translation-invariant probability measure $\mu .$ We characterize the countable groups $\Gamma $ of automorphisms of X for which the Koopman representation $\kappa $ on $L^2(X,\mu )$ has a spectral gap. More specifically, let Y be the maximal quotient solenoid of X (thus, Y is a finite-dimensional, connected, compact abelian group). We show that $\kappa $ does not have a spectral gap if and only if there exists a $\Gamma $ -invariant proper subsolenoid of Y on which $\Gamma $ acts as a virtually abelian group,
15 May 2023
TL;DR: In this paper , the authors present field measurements dedicated to the future calibration of a computational fluid dynamics model (PALM) involving an actuator disk to simulate a wind machine operating during radiative frost conditions.
Abstract: Spring frost has been recognized as the most harmful weather hazard for agriculture. One way to fight it back is using a wind machine - a 6-m diameter blowing fan atop a 10-m mast. It rotates on itself in approximately 4min30s and blows a slightly positive air using the strength of the nocturnal thermal inversion to mix cold air near the ground with warmer air above. Previous studies have focused on the protection area of the wind machine under different weather conditions or propeller designs. However, while weather conditions are undergone and field measurements are sparse, effects like the topography, the synergy between devices, or the addition of a burner are hard to catch and separate and are, therefore, not yet well understood.In this study, we present field measurements dedicated to the future calibration of a computational fluid dynamics model (PALM) involving an actuator disk to simulate a wind machine operating during radiative frost conditions. This numerical model will aim to understand better such tower's external effects, for which field measurements are challenging to implement.To characterize the jet of the propeller at the onset, vertical profiles were measured with a 3D sonic anemometer at high frequency (100Hz) 10 m away from the wind machine every meter between 3 and 15 m heights. Mass flow and momentum rates of about 500m3/s and 5000N were deduced for some different designs of wind machines.To characterize how the jet interacts with the ground regarding the distance from its source, 2D sonic anemometers were placed in a row in front of the wind machine. Results highlight three different zones where the jet behaved distinctively:A dead zone, where the jet passed over the ground (0 to 30 m away from the WM); An impact zone where the jet directly hit the ground with maximum velocity (40 to 60m away from the WM); A spreading zone where the protection mixing was due to eddies spreading in the inter-rows and breaking into smaller eddies in contact with posts and vine plants (70m away from the WM and beyond). As the distance from the machine increased, the jet velocity decreased before vanishing. From these results about the onset condition and development of the jet, it will be possible to tune the rotating actuator disk to reproduce with PALM (an LES meteorological-oriented modeling system) an acceptable behavior of the flows (gust and weather interacting with the ground) despite several simplifications of the underlying physics.While calibrations are still ongoing, the first results are encouraging, whether it be on a wind machine in a free environment or with the reproduction of a radiative night situation. The primary analysis will focus on the animation of state variables to assist in analyzing statistical results on field measurements. As little knowledge is available about the combined use of a burner with a wind machine, several strategies for a burner location will be tested in order to initiate a research topic that the authors believe is currently unexplored.
26 Mar 2023
TL;DR: In this article , the terahertz and infrared range diffraction radiation (DR) of a modulated beam of electrons flowing near two graphene-covered dielectric nanorods is analyzed.
Abstract: We analyze the terahertz and infrared range diffraction radiation (DR) of a modulated beam of electrons flowing near two graphene-covered dielectric nanorods. In our treatment, we assume that the velocity of the charged particles beam is fixed and use the Kubo formalism and resistive-type boundary conditions for the graphene cover description. To satisfy the boundary conditions, we apply the separation of variables in the local coordinates and the addition theorem for the cylindrical functions. This transforms the DR problem to a Fredholm second-kind matrix equation for the field expansion coefficients. As a result, the scattering and absorption characteristics and the near and far field patterns are determined with controlled accuracy. The obtained data show the resonance effects related to the excitation of the plasmon supermodes of four different classes of symmetry. Our work could be used in design of elementary cells of dielectric laser accelerators.
TL;DR: In this article , the authors conducted a series of twenty interviews with customers to understand how consumers react to retail offers of both types of businesses (i.e., franchised or independent), mainly in terms of the profiles of the entrepreneurs, their retailing mix, and their customer relationship management.
Abstract: Franchising is growing in most countries and most industries worldwide. Some people fear that chain-based businesses, including franchised businesses, will soon eliminate totally independent businesses. However, whatever the industry and the location, a coexistence of both franchised businesses and totally independent businesses is often noted. Our aim is thus to understand how consumers react to retail offers of both types of businesses (i.e., franchised or independent), mainly in terms of the profiles of the entrepreneurs, their retailing mix, and their customer relationship management. Our empirical study is based on a qualitative approach with a series of twenty interviews with customers. Our findings show that consumers have a very different store image of franchised and independent stores.
TL;DR: In this paper , the authors describe the clinical outcomes of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) therapy in their institution considering clinical context and pH at cannulation.
Abstract: We aimed to describe the clinical outcomes of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) therapy in our institution considering clinical context and pH at cannulation. All patients treated by VA-ECMO during the 2005-2020 period with 1 year complete follow-up were included. Our cohort was divided in three groups according to the pH level at cannulation: pH <7 (group 1), pH 7-7.2 (group 2), and pH>7.2 (group 3). Survival was analyzed using Kaplan-Meier method. Association between pH group and survival was estimated using a Cox model. A total of 572 patients were included: 60 patients in group 1, 115 in group 2, and 397 in group 3. Refractory cardiogenic shock (36%) was the main indication. One year survival rates were 13%, 36%, and 43% in groups 1, 2, and 3, respectively ( p < 0.001). Death mainly occurred within the first month. The strong correlation between pH and lactates led to propose a simple "three seven rule": pH <7 and lactate >7 was associated with <7% survival. Veno-arterial extracorporeal membrane oxygenation should be considered with caution in patients with pH <7. Lactates and pH might be important parameters to elaborate a new score to predict survival in this population. The "three seven rule" can be very relevant when facing emergency situations.