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Finite frequency Fault detection Observer Design for Takagi-Sugeno fuzzy systems
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Field-theoretic versus data-driven evaluations of electromagnetic corrections to hadronic vacuum polarization in
No full textInternational audienceThe Standard Model prediction of the muon increasingly depends on lattice QCD computations of the hadronic vacuum polarization (HVP), where the isospin-breaking (IB) effects remain a significant source of uncertainty. To complement the lattice QCD evaluations, the data-driven approach to HVP has been used to assess some of the electromagnetic IB effects, in particular from the channels with a photon in the final state, e.g., . Here we argue that such contributions are largely canceled by virtual electromagnetic corrections to the purely hadronic channels: , , etc. We identify these leading corrections by performing a field-theoretical calculation in a vector-meson dominance model, thereby reconciling the timelike and spacelike approaches to electromagnetic effects. Although these virtual corrections are more difficult to extract in a systematic manner, addressing them is essential for the data-driven method to consistently complement the lattice QCD program
Chromaticity of stellar activity in radial velocities: Anti-correlated families of lines on the M dwarf EV Lac with SPIRou and SOPHIE
No full textInternational audienceContext. In the search for exoplanets using radial velocities (RV), stellar activity has become one of the main limiting factors for detectability. Fortunately, activity-induced RV signals are wavelength-dependent or chromatic, unlike planetary signals. This study exploits the broad spectral coverage provided by the combined use of SOPHIE and SPIRou velocimeters to investigate the chromatic nature of the activity signal of the highly active M dwarf EV Lac.Aims. We aim to understand the origin of the strong wavelength dependence (chromaticity) observed in the RV signal of EV Lac by selecting spectral lines based on physical properties. In particular, we explore the impact of starspots by defining the contrast effect at the level of individual lines. The Zeeman effect is also considered in this study.Methods. SPIRou and SOPHIE spectra were reduced using the line-by-line (LBL) method. We performed custom RV calculations, using groups of spectral lines selected for their sensitivity to either the spot-to-photosphere contrast or the Zeeman effect. The sensitivity of each line to the spot is defined using a two-temperature model based on PHOENIX spectra, while Landé factors were used to quantify Zeeman sensitivity.Results. We find that the spectral lines are distributed in two distinct families of contrasts, producing anti-correlated RV signals. This leads to a partial cancellation of the total RV signal, especially at longer wavelengths and provides a natural explanation for the strong chromaticity observed in EV Lac. This sign-reversal effect is demonstrated here, for the first time, on empirical data. Building on this discovery, we propose a new approach to constraining spot temperatures and to mitigating stellar activity. This will open up promising avenues for improving activity corrections and enhancing the detection of exoplanets around active M dwarfs
Analysing vocal complexity in relation to sociality in orcas of British Columbia: An application of long-term computational passive acoustics
No full textInternational audienceOrcas are both highly social and highly vocal animals. In coastal waters of the North-Eastern Pacific Ocean, the Northern Resident orca population is well monitored, providing a great opportunity to learn about their social and communicative behaviour. Here, we report a series of acoustic analyses that lead to the empirical assessment of factors that might impact vocal complexity.Automatically processing long-term passive acoustic data, we detected and classified calls to transcribe vocal activity. Detailed post-hoc analyses show that the detection model is imperfect, especially in detecting calls of low energy. Also, diarisation is not possible with this data and transcriptions might gather a mixture of several emitters. Taking these limitations into account, we measured communicative complexity considering the groups' vocal production as a whole. Acoustic and visual cues also enabled the identification of specific groups with estimated numbers of individuals.Results highlight a positive correlation between vocal and social complexity, which could be due to the mere effect of having more potential emitters. Nonetheless, this brings a first demonstration of the non-trivial link between the number of emitters and complexity in the composition of sequences. We also demonstrate significant impacts of other proximate factors such as behaviour on vocal complexity measurements, and advocate for multi-factor considerations when evaluating communicative complexity.This work demonstrates the pertinence of joint efforts between passive acoustics, visual observations and machine learning to enhance the scale of behavioural studies and assess the validity of evolutionary hypotheses of communication systems.</div
Bioacoustic fundamental frequency estimation: a cross-species dataset and deep learning baseline
No full textInternational audienceThe fundamental frequency (F0) is a key parameter for characterising structures in vertebrate vocalisations, for instance defining vocal repertoires and their variations at different biological scales (e.g. population dialects, individual signatures). However, the task is too laborious to perform manually, and its automation is complex. Despite significant advancements in the fields of speech and music for automatic F0 estimation, similar progress in bioacoustics has been limited. To address this gap, we compile and publish a benchmark dataset of over 250,000 calls from 14 taxa, each paired with ground truth F0 values. These vocalisations range from infra-sounds to ultra-sounds, from high to low harmonicity, and some include non-linear phenomena. Testing different algorithms on these signals, we demonstrate the potential of neural networks for F0 estimation, even for taxa not seen in training, or when trained without labels. Also, to inform on the applicability of algorithms to analyse signals, we propose spectral measurements of F0 quality which correlate well with performance. While current performance results are not satisfying for all studied taxa, they suggest that deep learning could bring a more generic and reliable bioacoustic F0 tracker, helping the community to analyse vocalisations via their F0 contours
Beneficial influence of in-context predictability when young adults read with a simulated central scotoma
No full textInternational audienceConflicting results have been reported regarding the effect of word predictability when reading with eccentric vision. The present study aims to shed light on these discrepancies by investigating how in-context word predictability influences reading performance with a simulated scotoma, while considering the visual and lexical features of words. Thirty-five healthy young people read aloud sentences presented using the self-paced reading paradigm. A group of 22 participants practiced reading with a 10°diameter, gaze-contingent simulated central scotoma, with the other group serving as controls. Each participant underwent two in-lab sessions, reading 304 sentences (2-4 hours, depending on their group). Reading time, fixation number, and duration were analyzed for each target word using mixed-effect models. When reading with a simulated scotoma, in-context predictability shows a significant effect on performance, with a 35% decrease in reading time for highly predictable words compared with unpredictable ones (2.5 seconds vs. 1.6 seconds). This effect is modulated by practice, with the decrease dropping to 22% (1.3 seconds vs. 1.0 seconds) after only few hours of scotoma exposure. This effect seems to be driven by the total number of fixations required to identify words and is absent in the control group. These results support the hypothesis that reading with eccentric vision, which limits visual access to text, results in a stronger in-context predictability advantage. Moreover, this effect has a greater impact early in eccentric reading practice. This suggests greater reliance on linguistic inferences to compensate for impaired visual input, compared with central reading, at least until functional adaptation occurs.</div
NanoDSF Screening for Anti-tubulin Agents Uncovers New Structure–Activity Insights
No full textInternational audienceMicrotubule targeting agents (MTAs) constitute a vital category of tubulin-binding compounds deployed across anticancer therapies. Despite the array of MTA drugs developed by pharmaceutical entities, the quest for novel efficacious molecules continues unabated. We unveil an innovative in vitro MTA screening methodology employing nano-differential scanning fluorimetry (nanoDSF), presenting distinct advantages over known assays. This novel approach not only assesses compound-tubulin binding but also quantitatively analyzes its impact on tubulin polymerization, facilitating structure-activity relationship discovery. The proposed nanoDSF assay was rigorously validated using the Prestwick Chemical Library, which encompasses 1520 approved compounds, successfully identifying all previously known MTAs. This screening has unearthed potential antitubulin agents among drugs currently utilized for unrelated medical conditions, offering insights into their mechanisms of action in inhibiting cancer cell proliferation and/or inducing cytotoxicity. Finally, we have identified a previously unrecognized structure-activity relationship within the carbendazim and phenothiazine drug clusters, providing valuable insights for the rational optimization of compounds from these families. These discoveries open new opportunities for drug repositioning of the newly identified MTAs and significantly streamline the screening process of large chemical libraries for MTAs with novel chemical scaffolds.</div
