63 research outputs found
Decentralized model predictive control for smooth coordination of automated vehicles at intersection
International audienceWe consider the problem of coordinating a set of automated vehicles at an intersection with no traffic light. The priority-based coordination framework is adopted to separate the problem into a priority assignment problem and a vehicle control problem under fixed priorities. This framework ensures good properties like safety (collision-free trajectories, brake-safe control) and liveness (no gridlock). We propose a decentralized Model Predictive Control (MPC) approach where vehicles solve local optimization problems in parallel, ensuring them to cross the intersection smoothly. The proposed decentralized MPC scheme considers the requirements of efficiency, comfort and fuel economy and ensures the smooth behaviors of vehicles. Moreover, it maintains the system-wide safety property of the priority-based framework. Simulations are performed to illustrate the benefits of our approach
Nonlinear response of a gallium phosphide nanopatterned photonic waveguide in the CW regime
International audienceThe third-order Kerr nonlinear response in gallium phos-phide nanoscale waveguides is measured through continuous wave (CW) four-wave mixing. The extracted nonlinear coefficient ranges from about 800 W −1 m −1 to 1400 W −1 m −1 , consistently with an estimated material nonlinearity n 2 3.5 × 10 −18 W −1 m 2. The roles of the residual absorption and the related thermal effects are discussed
Reducing two-level system dissipations in 3D superconducting Niobium resonators by atomic layer deposition and high temperature heat treatment
Superconducting qubits have arisen as a leading technology platform for
quantum computing which is on the verge of revolutionizing the world's
calculation capacities. Nonetheless, the fabrication of computationally
reliable qubit circuits requires increasing the quantum coherence lifetimes,
which are predominantly limited by the dissipations of two-level system (TLS)
defects present in the thin superconducting film and the adjacent dielectric
regions. In this paper, we demonstrate the reduction of two-level system losses
in three-dimensional superconducting radio frequency (SRF) niobium resonators
by atomic layer deposition (ALD) of a 10 nm aluminum oxide Al2O3 thin films
followed by a high vacuum (HV) heat treatment at 650 {\deg}C for few hours. By
probing the effect of several heat treatments on Al2O3-coated niobium samples
by X-ray photoelectron spectroscopy (XPS) plus scanning and conventional high
resolution transmission electron microscopy (STEM/HRTEM) coupled with electron
energy loss spectroscopy (EELS) and (EDX) , we witness a dissolution of niobium
native oxides and the modification of the Al2O3-Nb interface, which correlates
with the enhancement of the quality factor at low fields of two 1.3 GHz niobium
cavities coated with 10 nm of Al2O3
Antimicrobial Susceptibility Profile of Several Bacteria Species Identified in the Peritoneal Exudate of Cows Affected by Parietal Fibrinous Peritonitis after Caesarean Section
peer reviewedAbstract: The aim of this study was to identify the species and antimicrobial susceptibility of
bacteria involved in parietal fibrinous peritonitis (PFP).We studied 156 peritoneal fluid samples from
cows presenting PFP after caesarean section. Bacteria were cultured in selective media and their
antimicrobial susceptibility was tested by disk diffusion assay. Bacteria were isolated in the majority
(129/156; 83%) of samples. The majority (82/129; 63%) of positive samples contained one dominant
species, while two or more species were cultured in 47/129 (36%) samples. Trueperella pyogenes (T.
Pyogenes) (107 strains) was the most identified species, followed by Escherichia coli (E. coli) (38 strains),
Proteus mirabilis (P. mirabilis) (6 strains), and Clostridium perfringens (C. perfringens) (6 strains). Several
other species were sporadically identified. Antimicrobial susceptibility was tested in 59/185 strains,
predominantly E. coli (38 strains) and P. mirabilis (6 strains). Antibiotic resistance, including resistance
to molecules of critical importance, was commonly observed; strains were classified as weakly drug
resistant (22/59; 37%), multidrug resistant (24/59; 41%), extensively drug resistant (12/59; 20%), or
pan-drug resistant (1/59; 2%). In conclusion, extensive antibiotic resistance in the isolated germs
might contribute to treatment failure. Ideally, antimicrobial therapy of PFP should be based upon
bacterial culture and susceptibility testing
Electrical spinal cord stimulation must preserve proprioception to enable locomotion in humans with spinal cord injury
Epidural electrical stimulation (EES) of the spinal cord restores locomotion in animal models of spinal cord injury but is less effective in humans. Here we hypothesized that this interspecies discrepancy is due to interference between EES and proprioceptive information in humans. Computational simulations and preclinical and clinical experiments reveal that EES blocks a significant amount of proprioceptive input in humans, but not in rats. This transient deafferentation prevents modulation of reciprocal inhibitory networks involved in locomotion and reduces or abolishes the conscious perception of leg position. Consequently, continuous EES can only facilitate locomotion within a narrow range of stimulation parameters and is unable to provide meaningful locomotor improvements in humans without rehabilitation. Simulations showed that burst stimulation and spatiotemporal stimulation profiles mitigate the cancellation of proprioceptive information, enabling robust control over motor neuron activity. This demonstrates the importance of stimulation protocols that preserve proprioceptive information to facilitate walking with EES
Opposite role of Bax and BCL-2 in the anti-tumoral responses of the immune system
BACKGROUND: The relative role of anti apoptotic (i.e. Bcl-2) or pro-apoptotic (e.g. Bax) proteins in tumor progression is still not completely understood. METHODS: The rat glioma cell line A15A5 was stably transfected with human Bcl-2 and Bax transgenes and the viability of theses cell lines was analyzed in vitro and in vivo. RESULTS: In vitro, the transfected cell lines (huBax A15A5 and huBcl-2 A15A5) exhibited different sensitivities toward apoptotic stimuli. huBax A15A5 cells were more sensitive and huBcl-2 A15A5 cells more resistant to apoptosis than mock-transfected A15A5 cells (pCMV A15A5). However, in vivo, in syngenic rat BDIX, these cell lines behaved differently, as no tumor growth was observed with huBax A15A5 cells while huBcl-2 A15A5 cells formed large tumors. The immune system appeared to be involved in the rejection of huBax A15A5 cells since i) huBax A15A5 cells were tumorogenic in nude mice, ii) an accumulation of CD8+ T-lymphocytes was observed at the site of injection of huBax A15A5 cells and iii) BDIX rats, which had received huBax A15A5 cells developed an immune protection against pCMV A15A5 and huBcl-2 A15A5 cells. CONCLUSIONS: We show that the expression of Bax and Bcl-2 controls the sensitivity of the cancer cells toward the immune system. This sensitization is most likely to be due to an increase in immune induced cell death and/or the amplification of an anti tumour immune respons
Priority-based coordination of autonomous and legacy vehicles at intersection
Recently, researchers have proposed various autonomous intersection
management techniques that enable autonomous vehicles to cross the intersection
without traffic lights or stop signs. In particular, a priority-based
coordination system with provable collision-free and deadlock-free features has
been presented. In this paper, we extend the priority-based approach to support
legacy vehicles without compromising above-mentioned features. We make the
hypothesis that legacy vehicles are able to keep a safe distance from their
leading vehicles. Then we explore some special configurations of system that
ensures the safe crossing of legacy vehicles. We implement the extended system
in a realistic traffic simulator SUMO. Simulations are performed to demonstrate
the safety of the system.Comment: put in other preprint serve
Immersive Data Exploration and Analysis
International audienceThis paper belongs to the emerging immersive analytics research field. It presents a system for exploratory analysis of multi-dimensional data focusing on providing freedom of locomotion while remaining comfortable for long user session. The solution allows to investigate temporal traces through a 3D scatterplot using a cylindrical coordinate system. Users are free to move inside the tracked area either standing up or seated in a mobile chair. A limited user study (n=6) has been conducted to investigate if the designed solution was deemed appropriate for mobility and user comfort
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