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Sur les approches intrinsèques en mécanique
No full textThis paper aims to illustrate the interest of so-called intrinsic or coordinate-free or geometric approaches in mechanics and to start a discussion about their positions with respect to the opposite aspects carried by computational mechanics. Due to recent developments of pure computational approaches using IA that could finally suggest that equations and formal developments are not necessarily so important in mechanics, it could obviously lead to philosophical and epistemological issues. Our main point of view can be summarized by the well-known sentence of René Thom: "To predict is not to explain". Even if we consider that stressing these questions in the community of mechanics should be fundamental and essential, it will not be however the theme of the present work. On the contrary, we will remain technic in order to defend the idea that intrinsic approaches are actually complementary to computational approaches in mechanics and that, even if these approaches may involve more abstract objects and less usual mathematical concepts, they can lead in fact to practically more efficient developments in applications. This thesis then defends the unity of mechanics and the non-sense to hermetically separate theoretical, computational and applied aspects in mechanics
Étude de cas. Vivendi : towards the end of the conglomerate?
No full textCas pédagogique CCMPInternational audienceVivendi, a French group, is currently present across the entire media and entertainment value chain (creation, publishing, and distribution of content) and in various markets through its subsidiaries as follows television and cinema (Canal+ group), book publishing (Lagardère), magazines (Prisma Media), video games (Gameloft), and advertising (Havas group). In December 2023, Vivendi announced in particular a plan to split the company into four publicly listed entities. These important strategic decisions have been completed in 2024, which appears to be a crucial year for the group. Is this the end of the conglomerate and/or the end of convergence strategy for Vivendi
Shotgun metagenomics reveals the flexibility and diversity of Arctic marine microbiomes
No full textInternational audiencePolar oceanographic regions are exposed to rapid changes in temperature, salinity, and light fields that determine microbial species distributions, but resilience to an increasingly unstable climate is unknown. To unravel microbial genomic potential of the Northern Baffin Bay’s polynya, we constructed eight metagenomes from the same latitude but targeting two sides of Pikialasorsuaq (The North Water) that differ by current systems, stratification, and temperature regimes. Samples from the surface and subsurface chlorophyll maximum (SCM) of both sides were collected 13 months apart. Details of metabolic pathways were determined for 18 bacteria and 10 microbial eukaryote metagenome-assembled genomes (MAGs). The microbial eukaryotic MAGs were associated with the dominant green algae in the Mamiellales and diatoms in the Mediophyceae, which tended to respectively dominate the eastern and western sides of Pikialasorsuaq. We show that microbial community taxonomic and functional signatures were ca. 80% similar at the latitude sampled with only 20% of genes associated with local conditions. From the metagenomes we found genes involved in osmotic regulation, antifreeze proteins, and photosystem protection, with hydrocarbon biodegradation and methane oxidation potential detected. The shared genomic compliment was consistent with adaptation to the Arctic’s extreme fluctuating conditions, with implications for their evolutionary history and the long-term survival of a pan-arctic microbiome. In particular, previously unrecognized genetic capabilities for methane bio-attenuation and hydrocarbon metabolism in eukaryotic phytoplankton suggest adaptation to dark conditions that will remain, despite climate warming, in the high latitude offshore waters of a future Arctic
Dynamics of X chromosome hyper-expression and inactivation in male tissues during stick insect development
No full textInternational audienceDifferentiated sex chromosomes are frequently associated with major transcriptional changes: the evolution of dosage compensation (DC) to equalize gene expression between the sexes and the establishment of meiotic sex chromosome inactivation (MSCI). Our study investigates the mechanisms and developmental dynamics of dosage compensation and meiotic sex chromosome inactivation in the stick insect species T. poppense . Stick insects are characterized by XX/X0 sex determination, with an X chromosome that likely evolved prior to the diversification of insects over 450 Mya. We generated a chromosome-level genome assembly and analyzed gene expression from various tissues (brain, gut, antennae, leg, and reproductive tract) across developmental stages in both sexes. Our results show that complete dosage compensation is maintained in male somatic tissues throughout development, mediated by upregulation of the single X chromosome. Contrarily, in male reproductive tissues, dosage compensation is present only in the early nymphal stages. As males reach the 4th nymphal stage and adulthood, X-linked gene expression diminishes, coinciding with the onset of meiosis and MSCI, which involves classical silencing histone modifications. These findings reveal the dynamic regulation of X-linked gene expression in T. poppense , and suggest that reduced X-expression in insect testes is generally driven by MSCI rather than an absence of dosage compensation mechanisms. Our work provides critical insights into sex chromosome evolution and the complex interplay of dosage compensation and MSCI across tissues and developmental stages
Organization performance in smart working settings: the mediating role of digital leadership
No full textABS 1International audiencePurpose - The development and diffusion of digital technologies, along with the pervasive dissemination of powerful and easy-to-use mobile devices, may encourage organizations to implement smart working (SW). This study investigates the relationship between the SW enabling resources and the organization performance. Furthermore, this study aims at analysing the mediating role of digital leadership on the relationship between the SW enabling resources and organization performance. Design/methodology/approach - This study adopted a case study approach to gather data on the underlying dimensions of the research model and a survey-based methodology to empirically test the proposed hypotheses. A total of 234 employees from one of the largest public utilities companies in Italy participated in the survey. After data cleaning, 209 questionnaires were deemed valid for analysis, yielding a response rate of 89.3%. Findings - The results of the PLS structural model analysis confirmed the pivotal role of resources and digital leadership on organizations’ performance. The findings reveal that all resources impact on organizational performance and highlight capabilities, such as digital leadership, as an explaining mechanism of the success in achieving optimal organization performance when implementing the SW. Practical implications - The findings have implications for companies that want to gain advantage by SW in terms of performance improvement. Specifically, the results indicate that companies are more likely to enhance their performance when implementing SW by adopting specific resources and developing capabilities as digital leadership.Originality/value - Despite the relevance of the resources (i.e. technologies, skills and culture) and digital capabilities in achieving optimal performance in organizations, their role in the effective implementation of SW has not been investigated in the academic literature, to the best of the authors’ knowledge. This study fills this gap by developing a research model grounded on the resource-based view theory to investigate the relationship between resources, digital leadership and organization performance in the context of SW implementation.</p
Adaptive Assimilation Control for Human–Robot Interaction With Limited Resolution: A Prescribed- Time Self-Triggered Quantized Approach
No full textInternational audienceIt is quite desirable yet challenging to plan specified motion behaviors from cooperation to opposition in terms of practical human-robot interaction tasks if the settling time, symmetric/asymmetric constraint, limited resolution, and less bandwidth occupation are involved. Based on this fact, this work is devoted to the assimilation control of human-robot interaction, which can flexibly reshape the physical trajectory in practical interaction work. Then, the adaptive parameter estimation terms are designed to address the effect of limited resolution and unknown robotic dynamics. In particular, a novel easy-to-implement self-triggered quantized mechanism is developed, which can better balance the relationship between system performance and resource utilization. Meanwhile, benefiting from the piecewise exponential function and bias state transformation, the practically prescribed-time stability of the controlled robotic dynamics can be guaranteed. The prominent feature of this design lies in that the settling time and convergence precision can be decoupled into separately user-preassigned parameters, and the symmetric/asymmetric output constraints can be implemented in a unified framework. Afterward, experiment results on a robot system verify the benefits and efficacy of the resultant scheme
Vers la disparition de la civilité Madame/Monsieur des formulaires ?
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Dionycoop, une épicerie pas comme les autres. Une source d’inspiration pour penser la soutenabilité ?
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Numerical simulation of band gap characteristics for periodically arranged curvilinear fiber laminated plates
No full textInternational audienceThis paper introduces curvilinear fiber laminated plates into the design of phononic crystal structures, proposing a model of periodic curvilinear fiber laminated plates and establishing a framework for band gap analysis. Specifically, we compare the band gap calculation results obtained using the finite element method (FEM) with those obtained using the plane wave expansion method, verifying the accuracy of our numerical approach. Based on this, we compare the band gap characteristics of curvilinear fibers and straight fibers, finding that the inclusion of curvilinear fibers significantly enhances the low-frequency band gap performance of the structure. Furthermore, we analyze the influence of the curvilinear fiber orientation parameters, discovering that these parameters affect the band gap characteristics of the structure. By adjusting the curvilinear fiber orientation parameters, it is possible to tailor the band gap properties to meet specific engineering requirements, greatly enhancing the design flexibility of the structure. Finally, we investigate the propagation of waves in various directions within the periodic curvilinear fiber laminated plates. Studies indicate that wave propagation in curvilinear fiber laminated plates exhibits more complex phenomena compared to straight fiber laminated plates. The patterns of wave energy flow also validate the effectiveness of the band gap