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Less is More: some Computational Principles based on Parcimony, and Limitations of Natural Intelligence
No full textNatural intelligence (NI) consistently achieves more with less. Infants learn language, develop abstract concepts, and acquire sensorimotor skills from sparse data, all within tight neural and energy limits. In contrast, today's AI relies on virtually unlimited computational power, energy, and data to reach high performance. This paper argues that constraints in NI are paradoxically catalysts for efficiency, adaptability, and creativity. We first show how limited neural bandwidth promotes concise codes that still capture complex patterns. Spiking neurons, hierarchical structures, and symboliclike representations emerge naturally from bandwidth constraints, enabling robust generalization. Next, we discuss "chaotic itinerancy", illustrating how the brain transits among transient attractors to flexibly retrieve memories and manage uncertainty. We then highlight reservoir computing, where random projections facilitate rapid generalization from small datasets. Drawing on developmental perspectives, we emphasize how intrinsic motivation, along with responsive social environments, drives infant language learning and discovery of meaning. Such active, embodied processes are largely absent in current AI. Finally, we suggest that adopting "less is more" principles -energy constraints, parsimonious architectures, and realworld interaction -can foster the emergence of more efficient, interpretable, and biologically grounded artificial systems
Prediction of Late Ventricular Arrhythmias in Patients with Left Ventricular Assist Device: Insights from the VT-LVAD Consortium
No full textInternational audienceNo abstract availabl
Pure Red Cell Aplasia Associated With Thymic Tumors, a Nationwide Retrospective Study
No full textInternational audiencePure red cell aplasia (PRCA) is the most frequent autoimmune cytopenia associated with thymic tumors (TTs). In a nationwide retrospective study, we included 41 patients (22 women, median age 62 years). At PRCA diagnosis, the mean hemoglobin level was 6.6 ± 2.1 g/dL, and the reticulocyte count was 6 ± 5 × 10 9 /L. PRCA was diagnosed before TT (8%, median delay 52 months), simultaneously (46%) or after TT (46%, median delay 34 months). Fourteen patients (34%) had definite Good syndrome. Thymectomy without immunosuppressive treatment provided a single sustainable PRCA response. Twenty‐two patients (54%) experienced multiple PRCA relapses (Median 2). When PRCA was present at TT diagnosis, the risk of PRCA relapse was higher ( p < 0.01), while TT staging, TT relapse, and Good syndrome were not associated with PRCA relapses. Corticosteroids led to a 77% initial response rate with frequent relapses during taper or at discontinuation. Cyclosporine A provided a 71% response rate. Overall response rates and time to response were similar with corticosteroids and cyclosporine A. Sirolimus led to a 50% response rate in refractory cases. Severe infectious events requiring hospitalizations were frequent (44%). After a mean follow‐up of 50 months, five patients (12%) died, three of whom died from TT relapse. Good syndrome was not significantly associated with an increased risk of infection, PRCA relapse, or death. Our findings highlight the severe phenotype of the association of TT and PRCA. While most patients achieve PRCA response under immunosuppressive therapy, high infection incidence and thymoma relapse are responsible for severe morbidity
Quantitative measurement of benthic foraminifera sediment reworking using a three-dimensional sensor
No full textInternational audienceDespite their worldwide distribution and very high densities, the contribution of benthic meiofaunal species to sediment reworking has largely been neglected in bioturbation research. This is partly due to the challenge in obtaining reliable measurements of these minute size organisms. So far, only a handful of studies have investigated the influence of these microbioturbators on particle transport processes at the sediment surface. These studies most often used the surface image analysis (SIA) method, which indirectly estimates surface sediment reworking rate (SSRR) by tracking the position of individuals at the sediment surface over time. Here, focusing on benthic foraminifera, we demonstrate that successive assessments of sediment microtopography mapping using a three-dimensional (3D) sensor can provide direct and accurate quantifications of meiofaunal SSRR, with high spatial and temporal resolutions. This new method is thus particularly suitable to investigating the as-yet-unknown influence of the meiobenthic fauna, such as foraminifera, on particle transport at the sediment–water interface and more generally on the functioning of benthic soft-bottom ecosystems
First measurement of reactor neutrino oscillations at JUNO
No full textInternational audienceNeutrino oscillations, a quantum effect manifesting at macroscopic scales, are governed by lepton flavor mixing angles and neutrino mass-squared differences that are fundamental parameters of particle physics, representing phenomena beyond the Standard Model. Precision measurements of these parameters are essential for testing the completeness of the three-flavor framework, determining the mass ordering of neutrinos, and probing possible new physics. The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid-scintillator detector located 52.5 km from multiple reactor cores, designed to resolve the interference pattern of reactor neutrinos with sub-percent precision. Here we report, using the first 59.1 days of data collected since detector completion in August 2025, the first simultaneous high-precision determination of two neutrino oscillation parameters, and for the normal mass ordering scenario, improving the precision by a factor of 1.6 relative to the combination of all previous measurements. These results advance the basic understanding of neutrinos, validate the detector's design, and confirm JUNO's readiness for its primary goal of resolving the neutrino mass ordering with a larger dataset. The rapid achievement with a short exposure highlights JUNO's potential to push the frontiers of precision neutrino physics and paves the way for its broad scientific program
Interplay between cohesin and TORC1 links chromosome segregation and gene expression to environmental changes
No full textInternational audienceCohesin is a DNA tethering complex essential for chromosome structure and function. In fission yeast, defects in the cohesin loader Mis4 result in chromosome segregation defects and dysregulated expression of genes near chromosome ends. A genetic screen for suppressors of the thermosensitive growth defect of mis4-G1487D identified several hypomorphic mutants of the Target of Rapamycin Complex 1 (TORC1), a conserved kinase that integrates cellular signals to regulate growth and metabolism through substrate-specific phosphorylation. Here, we demonstrate that the TORC1 pathway modulates cohesin functions in chromosome segregation and gene expression. In the context of compromised cohesin loading, the incidence of chromosome segregation defects was modulated by the growth medium in a TORC1-dependent manner. Pharmacological or genetic down-regulation of TORC1 activity restored cohesin binding to its chromosomal sites and improved mitotic chromosome segregation. Notably, reduced TORC1 activity also increased cohesin binding and chromosome transmission fidelity in wild-type cells. These results suggest that environmental cues influence chromosome stability via TORC1. Biochemically, TORC1 co-purified with cohesin and reduced TORC1 activity correlated with decreased phosphorylation of specific residues on Mis4 and cohesin. Mutations in cohesin that mimic the non-phosphorylated state mirrored the effects of TORC1 downregulation, showing that TORC1 is part of the network that controls cohesin phosphorylation to modulate its functions. Finally, we show that the functional interaction between TORC1 and Mis4 extends to the regulation of stress-responsive genes. Our findings reveal a TORC1-cohesin link that may facilitate cellular adaptation to environmental changes. Given that TORC1 inhibitors and calorie restriction extend lifespan in diverse species, this connection raises the intriguing possibility that cohesin-mediated changes in chromosome structure contribute to these effects
Solid-state NMR observation of chitin in whole cells by indirect 15N detection with NC, NCC, CNC and CNCC polarization transfers
No full textInternational audienceChitin is the most important nitrogen-containing polysaccharide found on Earth. This polysaccharide is a polymer of an N-acetylglucosamine and it is a crucial structural component of fungal cell walls and crustaceans. Magic-angle spinning solid-state NMR is emerging as a powerful analytical approach to study polysaccharides in the context of intact cell walls and whole cells. The presence of an acetamido group in chitin is attractive for 15N solid-state NMR. Here we investigate the use of various multi-step polarization transfer experiments incorporating indirect 15N detection at moderate spinning frequency, adapted from pulse sequences commonly employed for residue resonance assignment in biosolid proteins. The 13C,15N chitin spin topology slightly differs from amino acids, and we discussed the use of frequency-selective 15N-13C cross-polarization transfers followed by broadband or frequency-selective homonuclear 13C–13C transfers to detect chitin resonances. Demonstrated here for chitin found in the cell wall of the fungus Aspergillus fumigatus, the use of indirect 15N detection through multi-step polarization transfers could be advantageous to investigate more complex nitrogen-containing polysaccharides found in whole cells and peptidoglycan samples
Unlocking sugar subcellular dynamics: The crucial function and regulation of tonoplast sugar transporters in plant response to climate change
No full textInternational audienceAbstract Tonoplast sugar transporters are key regulators of intracellular sugar partitioning, mediating sugar flux between the cytosol and vacuole—an essential process for plant development and stress adaptation. Recent advances have deepened our understanding of well-characterized transporters such as TSTs and SWEETs, while also expanding the transporter repertoire with newly identified members including SWEET2, ERDL4, and SFP1/SAST1 across diverse plant species, including crops. Despite these insights, the regulatory mechanisms controlling transporter activity remain largely unresolved. This review aims to consolidate this expanding body of knowledge and explore in greater depth the molecular regulatory mechanisms controlling tonoplast sugar transporters. Additionally, we also analyze publicly available expression datasets to evaluate the potential of these transporters as targets for improving plant resilience under climate change conditions, particularly in response to elevated atmospheric CO₂. Ultimately, this review presents a new perspective on the significance of studying tonoplast sugar transporters, aiming to develop innovative strategies that enhance plant resilience to environmental challenges
Coordination between endodermal barriers and arbuscular mycorrhizae for nutrient exchange
No full textInternational audienceDuring arbuscular mycorrhizal symbiosis, fungal structures called arbuscules develop inside of plant cortical cells. Arbuscules are a site of intense nutrient exchange between both partners. However, the way these nutrients are transported to and from the vascular tissues is not known. This transport could involve the apoplastic, transcellular and symplastic pathways. The endodermis, being located between the cortical and vascular tissues, can affect this transport through the deposition of lignin and suberin, which block the apoplastic and transcellular pathways respectively. To understand the role of the endodermis in the development and functioning of arbuscular mycorrhizae, we used the model legume Medicago truncatula and the arbuscular mycorrhizal fungus Rhizophagus irregularis. The role of the apoplastic pathway was studied using Casparian strip mutants showing reduced lignin deposition. We observed that the absence of this barrier does not prevent mycorrhizal colonisation, and are now investigating the impacts of these mutations on plant and fungal nutrition through mass spectrometry approaches. For the transcellular pathway, we developed image analysis protocols to determine if suberin deposition is correlated with arbuscule formation. Furthermore, we created transgenic lines showing an induced or repressed suberin deposition. Results point to a negative correlation existing between suberisation and mycorrhizal colonisation. Last, the symplastic pathway is being studied using diffusible reporters allowing for the quantification of symplastic connectivity between the vascular and cortical tissues. This work aims to determine the involvement of each transport pathway in plant-fungi nutrient exchange, and how the modification of these pathways can affect global plant nutrition
Noradrenergic modulation of pheromone-induced odor learning and brain activation in newborn rabbits
No full textInternational audienceLearning maternal odors is crucial for mammalian newborns, who must locate the mother’s nipples to survive. In the newborn rabbit, the mammary pheromone (MP) present in the milk not only allows the pups to locate the nipples, but also promotes associative memory of neutral odorants. The noradrenergic system modulates neonatal learning in humans and rodents, but its role in newborn rabbits has never been investigated. Intraperitoneal injection of propranolol, a β-adrenoceptors antagonist, blocked acquisition, but not memory consolidation or retrieval, of MP-induced odor memory. Moreover, gene expression analyses revealed that propranolol attenuated c-Fos neuronal activation induced by odor learning in the olfactory bulb and to a lesser extent in the anterior piriform cortex, but not in the hippocampus, of rabbit pups. Interestingly, propranolol had no effect on c-Fos activation induced by MP alone indicating a specific effect of propranolol on neuronal activation induced by associative learning. These effects were not associated with a change in β-adrenoceptors expression in these brain areas. This highlights the crucial role of noradrenergic system in neonatal odor learning in mammals and suggest that the MP promotes odor learning by activating β-adrenoceptors in olfactory brain areas in rabbit pups. This pheromone-induced memory provides a great opportunity to explore the neurobiology of neonatal learning