HAL Université de Tours
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Cold vs. CO₂: anaesthetic effects on insect antennal functionality
No full textInternational audienceAnaesthesia methods play a crucial role in ensuring the integrity of the animal during experimental studies. This study investigates the impact of two anaesthesia methods, CO₂ and cold treatment, on an insect antennal response to synthetic alarm pheromone compounds. Adult worker hornets were anesthetised, and their antennae excised and tested using an electroantennography set-up with controlled stimulation of alarm pheromone components. Results showed that CO₂-anesthetised hornets exhibited robust antennal responses, while cold-anesthetised individuals displayed none. This result suggests that freezing may impair the functionality of olfactory receptors. In contrast, CO₂ anaesthesia preserves receptor integrity, offering reliable and interpretable results. This study highlights the importance of selecting appropriate anaesthesia techniques to avoid artefacts in insect sensory physiology research and underscores the ecological relevance of studying Vespa velutina nigrithorax alarm signalling
Impact of high CO2 concentration at the beginning of egg incubation on chicken metabolism and meat defects
No full textInternational audienceIn practice, hatcheries let CO2 concentration reach 1% at the beginning of egg incubation, limiting energy costs and improving hatching rates. However, the long-term consequences of this practice on the meat-type chicken metabolism, health and meat quality were scarcely explored. Therefore, this study aimed to analyse the effects of high CO2 concentration between days (I) I3 and I11 of incubation (up to 1%, CO2 group) compared to 0.1% CO2 concentration (Controls) on the embryo and chicken growth, chicken plasma metabolites and meat quality, especially meat defects related to muscle oxygen supply, depending on the animal sex. The 300 control eggs and 300 eggs treated with a transitory increase in %CO2 were incubated together before I3 and after I11 and separately between I3 and I11 of incubation. Embryo tissue and body weights (BW) were measured at I11 and I15. After hatching, 80 males and 80 females per group were reared together, before being weighted and laughtered at 40 days of age. After slaughter, meat processing quality and meat defects were evaluated. Embryo and tissue sampling during incubation showed that CO2 embryos were heavier at I11 than controls, which was still found at I15, with a trend for greater heart relative weight at this age (p=0.07). Hatching rates were high and did not differ between groups (93%). No apparent health issue was detected throughout the growth period. At 33 days of age, glycaemia and lactatemia of CO2 males only were greater than those of control ones. Finally, at slaughter, BW did not differ between groups, but the breast muscle of CO2 chickens was redder compared to controls. The incidence of the meat defect wooden breast was lower in CO2 males (76%) than in control males (88%), but greater in CO2 females (76%) than in control ones (51%). These results suggest that embryo hypercapnia has short-term and sex-dependent long-term physiological and metabolic effects impacting health and meat quality, for which the underlying mechanisms remain to be explored
The single machine adversarial bilevel total tardiness problem with job selection
No full textInternational audienceBilevel scheduling problems emerge in a variety of domains, including manufacturing and information systems. In these contexts, local schedulers interact with global decision centers in a system characterized by asymmetric information and self-interested behavior. Our study focuses on a particular case where a local scheduler aims to minimize total tardiness by assigning jobs to a single machine. The scheduler first submits the jobs to a dispatching center, which selects only a subset of them. Assuming that the selection criteria are unknown and do not take into account the scheduler’s objective, we consider the adversarial analysis, which evaluates the worst-case situation for the localscheduler, i.e., the case where the minimum total tardiness is the maximum among all possible job selections. From a computational perspective, this setting poses significant challenges in developing tight bounds and identifying partial job selections that yield suboptimal solutions. This is because the final schedule heavily depends on the full job selection. Nonetheless, in instances where the partial job selection exhibits specific characteristics, it is possible to derive an upper bound. Moreover, powerful job dominance conditions can be applied during the search process, and properties of optimal solutions can be used to rapidly identify good solutions. We propose an exact algorithm, derived from these results, that efficiently solves instances with more than a hundred jobs
Thermal sensing characteristics of Nd0.06Bi0.94FeO₃ NPs for thermistor applications
No full textInternational audienceHighly sensitive negative temperature coefficient (NTC) thermistors were developed using innovative and stable materials, including perovskites. This study explored the application of bismuth ferrite nanoparticles doped with 6 % neodymium in thermistors. These nanoparticles were synthesized using the Sol-gel method. X-ray diffraction analysis suggests that the Nd0.06Bi0.94FeO₃ NPs materials have a rhombohedral structure with an R3c space group. The crystallite sizes were determined using Scherrer's equation, yielding values of approximately 52 nm. Furthermore, the morphological characterization was performed through SEM and TEM analysis, revealing the formation of well-defined grain nanoparticles with an average size of 195 nm. Semi-quantitative energy-dispersive spectroscopy (EDS) analysis confirmed the presence of the anticipated elements Bi, Fe, Nd, and O, while no secondary elements were detected. The Raman analysis confirmed the structural stability of the Nd-modified BiFeO₃ nanoparticles. By studying the dielectric properties, the prepared material showed a negative temperature coefficient of resistance (NTCR) across various temperatures. Calculations of the thermistor constant (β) and sensitivity factor (α) confirmed its suitability as an NTC thermistor
Un programme d’accompagnement thérapeutique de la personne âgée vers l’entrée en EHPAD : protocole à cas unique
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Un programme d’accompagnement thérapeutique de la personne âgée vers l’entrée en EHPAD : protocole à cas unique
No full textInternational audienc
Water–energy–food–ecosystem nexus: how to frame and how to govern
No full textInternational audienceThe food, energy, and water domains are strongly interrelated. The body of literature investigating these interlinkages developed into water–energy–food and, more recently, ecosystem (WEFE) nexus thinking. The WEFE nexus is concerned with cross-sectoral resource management requiring dedicated WEFE governance approaches. Among the existing WEFE nexus conceptualizations, the one that places the ecosystem at the center emphasizes the importance of ecosystem services for human well-being and as the basis for the functioning of the water, energy, and food domains. Such conceptualization, however, lacks clear definition and explanation of implications for WEFE nexus governance as well as practical tools for implementation. Accordingly, based on an in-depth analysis of WEFE nexus interlinkages, associated governance challenges, and practical experience, we propose the WEFE Nexus Governance Approach as an operationalization of the ecosystem-centric WEFE nexus conceptual framework. This approach takes policy coherence and stakeholder co-creation at its core, integrated with quantitative modeling of WEFE nexus interlinkages, and is organized in four steps: problem identification; formulation of substantive ambitions through stakeholder dialogue; embedding of ambitions and action into a stakeholder agreement; and implementation of actions. The approach is oriented to practical application and can be implemented by any actor (e.g., research institutes, governments, non-governmental organizations) having the ambition to initiate a stakeholders co-creation process toward nexus governance in a specific context. Furthermore, it can be applied to different scales and nexus domains depending on the identified nexus problems, while accounting for the vital role of ecosystem services. The approach’s applicability and needs for future research are discussed
Quand la com’ s’emballe : le feu de paille du « starter pack »
No full textInternational audienceAdoptés par de nombreuses marques, les visuels de figurines sous starter pack ont rapidement envahi les réseaux sociaux. Derrière cette stratégie virale en apparence efficace se cache une communication mimétique, simplificatrice qui s’est rapidement trouvée en situation d’essoufflement. Une tendance qui en dit long sur les dérives de la communication à l’ère de l’instantanéité
Analyse du vieillissement cognitive dans l’autisme à travers les performances et le ressenti de difficultés
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A Beam Search for the Rolling Stock Corrective Maintenance Scheduling
No full textInternational audienceFor railway companies, rolling stocks are critical resources that need to be exploited at their maximum potential in order to respond to the transportation demand. Maintaining such fleets of trains is a very difficult task as their availabilities are very constrained. The moment and the place to fix a detected malfunction, while keeping the transportation plan stable for the users, is not an easy task, given that there may be multiple problems throughout the network. Deciding of the maintenance requests the resolution of a scheduling problem. The goal of this research is to provide an efficient solution to this problem. To achieve this, we develop a beam search, a fast tree search based heuristic able to provide quality solutions while having computation times compatible with the operational planning phas