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Dynamical system approach to the spectral (in)stability of black holes under localised potential perturbations
No full textThe aim of this work is to improve understanding of the resonant spectra of black holes under perturbations arising from e.g. compact objects or accretion disks in their vicinity. It is known that adding a weak perturbation to the radial potential can strongly disrupt the spectrum of quasinormal modes and Regge poles of a black hole spacetime. Here we examine the effect of (weak or strong) localised delta-function perturbations on the resonant spectra of spherically-symmetric systems, to address fundamental questions around linear and non-linear spectral stability. We examine two cases: the Nariai spacetime with a Poschl-Teller potential and the Schwarzschild spacetime. We show that, in either case, the spectrum deforms in a smooth and continuous manner as the position and strength of the perturbation is varied. As the strength of the perturbation is increased, resonances migrate along trajectories in the complex plane which ultimately tend towards attracting points determined by a hard-wall scenario. However, for weak perturbations the trajectory near the unperturbed resonance is typically strongly influenced by a set of repelling points which, for perturbations far from the system, lie very close to the unperturbed resonances; hence there arises a non-linear instability (i.e. the failure of a linearised approximation). Taking a dynamical systems perspective, the sets of attracting and repelling spectral points follow their own trajectories as the position of the perturbation is varied, and these are tracked and understood
Cost-optimal hydrogen refueling scheduling for bus fleet in a grid-connected hybrid renewable energy system
No full textInternational audienceThis study presents a cost-optimal sizing and energy management approach for a grid-integrated hybrid renewable energy system—comprising solar PV, wind turbines, and hydrogen production via electrolyzers with compressed storage—to meet both the electricity demand of Dijon, France, and hydrogen demand for mobility. To better plan the refueling of the hydrogen bus fleet, two case scenarios are analyzed: (i) refueling is flexibly scheduled over 24 h and (ii) refueling is optimally scheduled but restricted to 3–7 h, both for cost optimization. A Mixed-Integer Linear Programming (MILP) model is formulated and solved in the developed tool KLMS-OPT using the Pyomo modeling interface in Python with the objective of minimizing total annual cost. In the flexible scenario compared to the restricted scenario, the optimal configuration reduces the number of electrolyzers and refueling points from three to one. The hydrogen storage capacity remains below 100 kg, avoiding the need for legal authorization required in France for larger installations. This configuration yields a 0.35 % reduction in annual cost. Ultimately, the formulated problem in KLMS-OPT demonstrates strong computational efficiency, solving all scenarios in less than 20 min
Does the ecological transition pose a threat to the cultural worldview of the responsibilized consumer?: An exploration of social justice concerns within national sustainability policies.
No full textInternational audienceIn line with the European Green Deal, national governments across Europe have introduced a wide array of regulatory, incentive-based and facilitative measures to accelerate the ecological transition. These policies have substantial implications for household consumption. This research investigates how such national sustainability measures impact the cultural worldview of the responsibilised consumer—a central figure in neoliberal approaches to sustainability, defined by a moral agency oriented toward informed climate-friendly choices. While prior studies show that even environmentally concerned consumers can experience psychological and social tensions when adopting particular prescribed conduct, consumer research has rarely examined how individuals interpret ecological measures holistically and relate them to the broader cultural standards that underpin the value of individual conduct. In particular, moral concerns about social justice—despite their prominence in recent public debates and protest movements—remain understudied in marketing research on the ecological transition.Drawing on the theoretical lens of expectation violations, we examine whether the sustainability policy landscape, taken as a whole, may threaten the social stability of consumers’ worldviews, thereby generating cognitive dissonance and weakening identification with responsibilisation. We adopt an exploratory sequential mixed-methods design. Study 1 consists of qualitative interviews in France (n = 43), which reveal that ecological transition policies are perceived as raising major social justice issues. These perceptions cluster around three types of threats to social stability: (1) technological inequalities affecting older or digitally excluded consumers; (2) territorial disparities in public infrastructure between urban and rural areas; and (3) income-based barriers to accessing green products. Building on these insights, Study 2 uses an online experiment (n = 300) to test the effects of a sustainability measure involving territorial inequalities. Results show that perceived threats to societal stability significantly mediate the relationship between the ecological measure which is associated with territorial inequalities and cognitive dissonance.This research extends the existing literature on consumer responsibilisation by shifting the focus from discrete consumption practices to consumers' justice-related interpretations of the ecological transition as a policy system. The study demonstrates the value of drawing on consumers' cultural worldviews to fully grasp the issues at stake in terms of the acceptability of transition measures. From a policy standpoint, the findings emphasise the necessity for more inclusive sustainability narratives and infrastructural strategies that acknowledge social and territorial inequalities. This is an essential condition for avoiding disidentification with ecological objectives and securing broader public support for the transition
Transforming Raw Text into Structured Data: An Overview of Content Analysis and Natural Language Processing Techniques for Sensory and Consumer Science
No full textInternational audienc
Economic policy uncertainty, ESG practices, and investment inefficiency in U.S. firms
No full textInternational audienceThis study examines how economic policy uncertainty (EPU) influences the efficiency of corporate investments and whether strong environmental, social, and governance (ESG) practices impact this relationship. Using data on U.S. firms from 2010 to 2022, we find that higher EPU leads to greater investment inefficiency, including both under- and overinvestment. When faced with uncertainty, firms tend to favor R&D over capital expenditures, reflecting a preference for flexibility. We also show that information asymmetry intensifies the negative impact of uncertainty on investment decisions. Importantly, robust ESG practices help mitigate the adverse impact of EPU by easing financial constraints and reducing information asymmetry. These results highlight the value of ESG as a stabilizing force in uncertain environments. More broadly, the study underscores the importance of integrating ESG considerations into corporate strategies to foster stability and sustainable growth amid evolving economic conditions
Experimental evolution of Plasmodium yoelii in single and helminth-coinfected mice.
No full textInternational audienceBackground Coinfection has the potential to affect key traits describing the infection dynamics, the severity of the disease and in fine parasite fitness. However, despite its pervasiveness, experimental work investigating how parasites adapt to the conditions provided by a coinfected host is mostly missing. Methods We adopted an experimental evolution approach to investigate if coinfection with the nematode Heligmosomoides polygyrus (Hp) affected the infection dynamics and virulence of the murine malaria parasite Plasmodium yoelii (Py). To this purpose, lines of Py were passaged either in single infected hosts (SI-lines) or in hosts that had been previously infected with Hp (COI-lines). After five and seven passages, the infection dynamics and virulence of evolved lines were compared to the ancestral Py population during single infection trials. COI-lines were also used to infect hosts during coinfection trials, allowing us to compare within-host Py replication when the environment during the evaluation trials matched the environment experienced during the passages and when the two environments were mismatched. Results We found that serial passages increased parasitemia and Py virulence, due to the competitive advantage of genotypes with the fastest replication rate, but SI-lines and COI-lines had relatively similar replication rate and virulence. Hosts infected with evolved lines of Py were also less tolerant (steeper slope between red blood cell counts and parasitemia) but there was no difference between SI-lines and COI-lines. Finally, we found that when COI-lines were used during single infection trials (mismatched environments), they had a slower early replication rate compared to matched-environment trials. Conclusions We did not find strong evidence supporting a divergence between the virulence of SI-lines and COI-lines, possibly due to the cost of virulence paid by COI-lines. However, Py rapidly adapted to the environmental conditions provided by single infected or coinfected hosts, as shown by the slower replication rate found in mismatched-environment trials
Couture et suture autour de la figure de Marie-Madeleine: « The Map » d’Alice Maher et Rachel Fallon (2021)
No full textInternational audienceEn 2021-2022, le Centre d’Arts Rua Red à Dublin a accueilli la « Magdalene Series », un ambitieux programme d’expositions, de spectacles et d’événements centrés sur la figure ambivalente de Marie-Madeleine et son héritage pour les femmes d’Irlande, notamment à travers la religion catholique mais aussi parce qu’elle est directement associée à l’incarcération et l’institutionnalisation de jeunes femmes dans des blanchisseries correctives dites « de Marie-Madeleine » durant plus de deux siècles (18è-fin du 20è siècle). « The Map », œuvre textile monumentale réalisée par Alice Maher et Rachel Fallon était l’une des pièces maîtresses de cette « Magdalene Series ». Représentant tout un monde suivant le modèle d’une projection conique de Lambert et constituée d’un patchwork coloré de tissus rehaussé de broderies, d’incrustations, de petites pièces au crochet et de motifs peints, la tenture de Maher et Fallon cartographie le territoire des femmes et imagine tout en la réinventant l’influence de Marie-Madeleine sur elles. Les artistes brodent l’odyssée de la vie des femmes d’un continent à l’autre de leur existence et nous donnent à voir tout en le défaisant l’immense écheveau des chaines qui les entravent : domesticité et patriarcat, moralité et puritanisme, sexisme.Dans notre présentation, nous nous efforcerons de montrer comment cette Mappa Feminei Mundi, réalisée à quatre mains durant trois périodes de confinement, reprend l’une des activités les plus emblématiques des femmes, le travail d’aiguille, pour dénoncer la violence à la fois physique et psychique faite aux femmes irlandaises au fil des siècles. Nous montrerons comment cette « sculpture textile » comme aiment à la définir les deux artistes est une forme de militantisme et de résistance mais aussi de réparation. En effet, si l’on prend un peu de recul et que l’on observe l’œuvre dans son ensemble, c’est un corps de femme que l’on reconnait, celui de Marie-Madeleine couronné par sa célèbre chevelure rousse tissée de fils d’or et représenté ici en majesté
Chapter 11 - Organ communication in insects during growth and development
No full textInternational audienceThis chapter aims at summarizing examples of organ communication and formulating possible underlying principles about the cellular and molecular pathways in insect development and growth. Some of these examples of organ communication are explicitly verbalized as a problem of organ communication in the literature, while others are not, and therefore their inclusion here relies on my interpretation. Generally, we distinguish between the embryo that develops and differentiates in a closed system within the egg case and the stages outside the embryo and before metamorphosis that constantly receive information especially nutrients from an open system, the environment
Ensuring colloidal stability of cisplatin-loaded mesoporous silica nanoparticles: from synthesis to cytotoxicity assays
No full textInternational audienceMesoporous silica nanoparticles (MSNs) have attracted significant attention as a promising drug delivery platform for cancer treatment. However, their colloidal stability often remains overlooked, despite the numerous drawbacks associated with its absence. In this study, the enhancement of the colloidal stability of thoroughly characterised (TEM, DLS, zeta potential, TGA, XRD, N 2 physisorption) monodisperse MCM-41 MSNs in physiological conditions through the grafting a comb-like copolymer was successfully accomplished (preservation of the hydrodynamic diameter and the polydispersity index for at least 3 days). The loading of a therapeutic agent, cisplatin, was then achieved (12 wt%) without compromising their colloidal stability, and drug release kinetics were evaluated in cell culture medium, observing a complete release of the cargo after 48 h. Cytotoxicity studies conducted before and after drug loading confirmed the innocuousness of unloaded MSNs and demonstrated cytotoxic effects comparable to those of free cisplatin for the loaded nanoparticles (IC 50 = 23 and 13 μM CDDP for loaded MSNs versus 24 and 11 μM CDDP for free cisplatin in, respectively, SW480 and A549 cell lines).Particular emphasis was placed on ensuring the reproducibility of the results (e.g., hydrodynamic diameter and polydispersity index were measured across 49 independent synthesis) and on thoroughly evaluating the colloidal stability of the nanoparticles throughout the study, from synthesis to cytotoxicity assays. To the best of our knowledge, this work represents the first systematic study of the conditions required to develop stable colloidal suspensions of monodispersed mesoporous silica nanoparticles loaded with cisplatin, achieving high reproducibility, which constitutes a novel and robust contribution to the field.</p
Proteomic profile data of Klebsormidium nitens alga grown in control and saline conditions
No full textInternational audienceKlebsormidium nitens (K. nitens) is an alga of the charophyte class used as a model for studying the adaptation of plants to terrestrial life. Its genome has been completely sequenced and 16,215 protein-coding genes have been predicted. In this study, the proteome of K. nitens grown under standard conditions or after salt stress was investigated. A total of 1190 proteins were experimentally confirmed and 922 of them were classified according to their cellular location, molecular or biological function. Of these 922 proteins, 62 and 124 were specifically found in the control and salt-treated samples, respectively. However, no specific function or location could not be assigned on the basis of the primary sequences. A protein-protein interaction network based on the 124 proteins found in saline conditions was constructed using STRING analysis. All the data are accessible and are of interest for phycologists, as well as for evolutionary plant biologists, and provide a foundation for future studies investigating how K. nitens responds to salt stress