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State and Unknown Input Estimation using a Left-Invertibility Constrained NeuralEstimator in Delayed Autonomic Cardiac Dynamics
No full textInternational audienceUnderstanding brain–heart interaction (BHI) requires models that capture how thecentral nervous and cardiovascular systems co-regulate under stressors to preserve homeostasis and generate macroscopic states such as sleep, arousal, or vigilance. At the core of this loop are interoceptive variables, latent autonomic control signals that drive cardiac adjustments; however, these variables are not directly measurable. Recovering these hidden drives from peripheral cardiac recordings is confounded by nonlinear dynamics, physiological delays, and limited measurement data. This work proposes a physics-informed neural estimator for joint state estimation and unknown autonomic input reconstruction in a delayed nonlinear model of autonomic cardiac regulation. The framework derives left-invertibility conditions from the delay-free system and determines a system-intrinsic bound on physiological delay driven only by heart-rate dynamics, preserving constraint validity for the delayed system within that bound.Validation on stress-evoked cardiac recordings shows accurate recovery of heart rate, blood pressure state estimation, and input reconstruction (the blood-pressure setpoint), enabling identifiable, physiology-consistent inference of interoceptive autonomic control dynamics
Moderating Effect of NICTs on Marketing Effectiveness and Export Performance of African Firms: The Impact of Gender and Manager Experience
No full textInternational audienc
A glitch in the millisecond pulsar J09003144
No full textInternational audienceWe report the detection of a glitch in the millisecond pulsar (MSP) PSR J09003144, which is included in the European, MeerKAT and Parkes pulsar timing array experiments. The dataset combines observations from the MeerKAT, Nançay, Lovell, and Murriyang telescopes, spanning a total baseline of approximately 14 years. The glitch occurred on MJD~59942(17), with a measured fractional spin frequency step of . This event represents the third glitch detected in a MSP, following those in PSRs B182124A and J06130200. Although smaller in amplitude than the previous two, the glitch in PSR J09003144 is of a comparable order of magnitude. The updated MSP glitch rate is glitches per pulsar per year, which suggests it is likely current PTAs will detect another MSP glitch within five years. Using simulations, we demonstrate that such small glitches can go undetected, especially in short datasets such as those from new PTAs, and can bias the inferred achromatic noise model parameters, potentially leading to the down-weighting of the pulsar in gravitational wave background searches
Shapiro Delay Measurements from Fifteen Years of PSR J12311411 Radio Observations
No full textInternational audienceWe present 15 years of Nançay and Green Bank radio telescope timing observations for PSR J12311411. This millisecond pulsar is a primary science target for the Neutron Star Interior Composition Explorer telescope (NICER, which discovered its X-ray pulsations), has accumulated near-continuous -ray data since the Fermi-Large Area Telescope's launch, and has been studied extensively with the Green Bank and Nançay radio telescopes. We have undertaken a campaign with the Green Bank Telescope targeting specific orbital phases designed to improve our constraint on the pulsar's mass through the detection of a relativistic Shapiro delay. Both frequentist and Bayesian techniques -- the latter incorporating priors from white dwarf binary evolution models -- are applied to fifteen years of radio observations, yielding relatively weak constraints on the companion and pulsar masses of M and M, respectively (68.3% CI from Bayesian fits); however, the orbital inclination is measured to better relative precision ( degrees). Restricting the maximum allowed pulsar mass to 3 M while simultaneously sampling the noise and timing models improves the constraint and lowers the measured mass to M. While our radio-derived inclination result has informed recent NICER X-ray studies of PSR J12311411, the lessons learned from this troublesome pulsar will also bolster future high-precision mass measurement campaigns and resulting constraints on the neutron star interior equation of state
LIM kinase/inhibitor binding study in cell lysates using microscale thermophoresis in the red spectrum
No full textInternational audienceBackground: Cellular function depends on complex molecular interactions that activate signaling pathways - central to drug discovery projects. LIM kinases (LIMKs) are attractive therapeutic targets implicated in various diseases, yet no clinically approved LIMK inhibitors exist, likely due to limited understanding of their molecular behavior under near-physiological conditions. This breach stems in part from the difficulty in purifying these proteins. To address this, there is a crucial need for a simple and rapid method to determine LIMK-inhibitor binding affinities (Kd values) directly in cell lysates, bypassing challenging purification and immobilization steps.Results: The monomeric near-infrared fluorescent protein miRFP670 (excitation/emission: 640/680 nm) is an advantageous fluorescent tag for microscale thermophoresis (MST) assays in cell lysates. The miRFP670-tagged LIMKs were successfully overexpressed in HEK293 cells, characterized, and validated by western blotting. MST assay conditions - including MST buffer composition and target storage - were carefully optimized and negative controls were consistently used to ensure data reproducibility as well as assay specificity. The MST conditions were as follows: miRFP670-kinases at a fixed concentration of a few tens of nM in cell lysate supplemented with 30 % (v/v) glycerol for convenient storage; 0.005 % (v/v) DMSO in the MST buffer; 37 ◦C; 20 % LED power; medium MST power; and standard capillaries. The presence of 0.1 % Triton X-100 in the MST buffer was essential to prevent protein aggregation, as evidenced by smooth MST time traces. The reproducibility and stability of signals across all capillaries attest to the optimality of the incubation conditions and the attainment of a stable binding equilibrium. This consistency also validates the robustness of the assay. MST analysis of cell lysates yielded Kd values for full-length and kinase domains and show strong agreement with literature where available. Notably, sub-micromolar Kd values were confirmed for the reference inhibitors LX7101, BMS-5, and TH-257, with slight differences observed between full-length LIMKs and their kinase domains - differences often overlooked in the literature.Significance and novelty: This work establishes the first detailed production, characterization, and use of miRFP670 in MST-based evaluation of biomolecular interactions under near-native conditions. miRFP670 operates in a spectral region (red) with minimal cellular autofluorescence, enhancing signal specificity and sensitivity. This approach offers a straightforward and broadly applicable, purification-free platform for early-stage drug discovery
Combustion of NH3/CH4 mixtures in a swirl burner: Study of non-premixed flames with radial fuel injection
No full textInternational audienceThe transition to renewable energy is essential in addressing climate change. While natural gas plays a significant role in this transition, it still produces CO2 emissions. Ammonia (NH3) is being investigated as a promising alternative fuel. However, ammonia combustion presents several technical challenges, such as low flame velocity, limited calorific value, difficulties with flame stabilization, and high NOx emissions. This study examines the impact of ammonia addition to methane, equivalence ratio, and swirl number on pollutant emissions (NO, CO, CH4, and CO2), exhaust gas temperature, and flame stability. Experiments are carried out using a swirl burner with a radial fuel injection in a 1-meter high combustion chamber. The burner consists of two concentric tubes, with the inner tube supplying fuel and the outer tube supplying air. The fuel is injected radially through eight holes at the burner exit. The ammonia fraction ranges from 0 to 100 %, the equivalence ratio from 0.8 to 1.0, and the swirl number from 0.8 to 1.4, with a constant flame power of 10 kW. Emissions of NO, CO, CH4, and CO2 are measured in the dry exhaust gases using a multi-gas analyzer, inside chamber temperatures are measured and the flame structure is analyzed via OH* and NH2* chemiluminescence and velocity measurements by LDA technique. The results show that both the swirl number and equivalence ratio significantly alter flame geometry, affecting combustion zones and flame height. Axial velocity measurements indicate that the recirculation zone shrinks with ammonia addition, while a high swirl number increases axial velocity, promoting ammonia combustion and upstream flame propagation. Up to 30 % ammonia, the flame remains stable, but higher ammonia levels lead to fluctuations in stabilization. High ammonia content in the fuel mixture results in reductions of NO, CO, and CO2 emissions, though there is a potential increase in unburned gases. As expected, the inside chamber temperatures decrease as the ammonia fraction increases
Stroke rate and arm coordination management in swimming in a double Paralympic triathlete champion
No full textInternational audienceThe 2024 Paris Paralympic triathlon required swimming with and against the current which requested to adapt stroke mechanics. To understand how a Paralympic triathlete champion might adapt his stroke mechanics under varying current conditions, this study aimed to 1) determine the range and optimal stroke rate (SR) and index of coordination (IdC); 2) examine the flexibility of SR, IdC and associated total energy expenditure. The para triathlete performed two front crawl tests: 10 times 25m incremented in swimming speed (S), from which S-SR and S-IdC relationships have been modelled to detect two regimes of functioning and the most effective SR; then, 6 times 50 m at the speed of the 800 m freestyle using 6 different SR conditions: spontaneous SR (SRs), SRs imposed by tempo trainer, SRs+3, SRs+6, SRs-3 and SRs-6 cycles. Total energy expenditure was computed from post-exercise oxygen uptake and blood lactate measurements. In test 1, the highest effective SR equals 44 cycle.min-1, which corresponds to the preferred SR in 800 m freestyle competition. In test 2, the para triathlete struggled to perform the high SR conditions, which was associated to higher total energy expenditure; conversely, the para triathlete naturally decreased SR. It is advised to modulate SR around the preferred SR to optimise efficiency under varying current conditions.</p
Detailed assessment of combustion risk and PAR efficiency in the late phase of a severe accident within the European AMHYCO project
No full textInternational audienceThe European AMHYCO project aims at enhancing the understanding of H2/CO combustion risk within the containment of a light water reactor nuclear power plant during the in- and ex-vessel phase of a severe accident. The goal is to incorporate this knowledge into severe accident management guidelines (SAMG) and give recommendations for long-term operation upgrades. Based on a critical review of established methodologies and practices related to combustion risk assessment, as well as the identification of accident sequences where the containment integrity may get challenged, experimental investigations were conducted to close knowledge gaps related to combustion characteristics and the operation of passive autocatalytic recombiners under late phase conditions. To prepare the basis for the further assessment and refinement of existing SAMGs, systematic and detailed analyses of the most challenging scenarios and possible mitigative measures were conducted for three generic European pressurized water reactor (PWR) containment designs, namely KWU, Westinghouse, and VVER. For each reactor type, one Loss of Coolant Accident and one Station Blackout scenario were selected for detailed analyses with a variety of different numerical codes. Both scenarios cover a range of in-containment atmospheric conditions from potentially flammable at medium pressure to a steam-inerted atmosphere at high pressure, including the late phase with an active filtered containment venting system (FCVS). This paper outlines the employed methodology using a consecutive analysis chain consisting of three levels with increasing level of detail (system codes, 3D GOTHIC™ and CFD) to assess containment pressurization, efficiency and/or options of individual mitigation measures regarding H2/CO combustion risk and equipment and instrumentation survivability. As a common basis, the system code nodalization schemes and 3D models are developed from detailed CAD geometries. On the basis, the paper summarizes the outcome of the work with a focus on the comparative assessment of the impact and effectiveness of mitigative measures (passive autocatalytic recombiner, containment sprays, FCVS) on the combustion risk in the accident. The analyses highlight that without combustible gas mitigation, containment atmospheres develop combustible pockets and may even become globally flammable, highlighting the need for control systems to preserve integrity. PARs proved effective across all scenarios in preventing large clouds with flame acceleration conditions, with their capacity mainly influencing depletion rates and timing. Oxygen removal by PARs also enables safe operation of containment and core cooling systems without increasing combustion risk in the late phas
Turbulence-Driven Corrugation of Collisionless Fast-Magnetosonic Shocks
No full textInternational audienceCollisionless fast-magnetosonic shocks are often treated as smooth, planar boundaries, yet observations point to organized corrugation of the shock surface. A plausible driver is upstream turbulence. Broadband fluctuations arriving at the front can continually wrinkle it, changing the local shock geometry and, in turn, conditions for particle injection and radiation. We develop a linear-MHD formulation that treats the shock as a moving interface rather than a fixed boundary. In this approach the shock response can be summarized by an effective impedance determined by the Rankine-Hugoniot base state and the shock geometry, while the upstream turbulence enters only through its statistics. This provides a practical mapping from an assumed incident spectrum to the corrugation amplitude, its drift along the surface, and a coherence scale set by weak damping or leakage. The response is largest when the transmitted downstream fast mode propagates nearly parallel to the shock in the shock frame, which produces a Lorentzian-type enhancement controlled by the downstream normal group speed. We examine how compression, plasma , and obliquity affect these corrugation properties and discuss implications for fine structure in heliospheric and supernova-remnant shock emission
Convergence vers les lois stables pou des produits de matrices aléatoires
No full textUnder reasonable algebraic assumptions and under an infinite second order moment assumption, we show that the logarithm of the norm (log-norm) of a product of random i.i.d. matrices with entries in or in any other local field satisfies a generalized Central Limit Theorem (GCLT) in the sense of Paul Lévi.The proof is based on a weak law of large number for the difference between the log-norm of the product of the first matrices and the sum of their log-norms. This weak law of large numbers morally says that behaves like a sum of i.i.d. random variables that have a finite moment of order as long as the log-norm of each matrices has a finite moment of order q for a given .This gain of moment is the central result of the present paper and is based on the construction of pivotal times. Moreover, these results admit a nice higher rank extension when one looks at the full Cartan projection instead of the log-norm.Sous de hypothèses algébriques raisonnables et une condition de moment d'ordre infini, on démontre que le logarithme d'un produit de matrices aléatoires indépendantes et de même loi, à coefficients réelles ou dans un corps localement compact, satisfait un théorème central limite généralisé au sens de Lévi.La preuve fait intervenir une loi faible des grands nombres pour la différence entre le log de la norme du produit de matrices et la somme de leurs log-normes. Cette loi faible des grand nombres diten gros que se comporte comme une somme de variables aléatoires indépendantes dont la loi commune a un moment d'ordre fini là où le log-norme de chacune des matrices a un moment d'ordre fini pour un certain q > 0.Ce gain de moment est central dans le résultat du présent article et est obtenu via la construction de temps pivots. De plus, ces résultats admettent une généralisation en rang supérieur dès qu'on regarde la projection de Cartan totale au lieu du log-norme