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How does a social scientist become a deeptech entrepreneur? The strengths and limitations of the French academic innovation ecosystem
No full textInternational audienc
Model Order Reduction based on Direct Normal Form: Application to Large Finite Element MEMS Structures Featuring Internal Resonance
No full textInternational audienceDimensionality reduction in mechanical vibratory systems poses challenges for distributed structures including geometric nonlinearities, mainly because of the lack of invariance of the linear subspaces. A reduction method based on direct normal form computation for large finite element (FE) models is here detailed. The main advantage resides in operating directly from the physical space, hence avoiding the computation of the complete eigenfunctions spectrum. Explicit solutions are given, thus enabling a fully non-intrusive version of the reduction method. The reduced dynamics is obtained from the normal form of the geometrically nonlinear mechanical problem, free of non-resonant monomials, and truncated to the selected master coordinates, thus making a direct link with the parametrisation of invariant manifolds. The method is fully expressed with a complex-valued formalism by detailing the homological equations in a systematic manner, and the link with real-valued expressions is established. A special emphasis is put on the treatment of second-order internal resonances and the specific case of a 1:2 resonance is made explicit. Finally, applications to large-scale models of Micro-Electro-Mechanical structures featuring 1:2 and 1:3 resonances are reported, along with considerations on computational efficiency
Bereavement meanings and the conditions for successful social support service encounters
No full textInternational audiencePurpose Bereavement is far reaching and has a significant impact on many lives as widow(er)s are faced with countless changes to their everyday routines, their relationships and their consumption patterns. It is in this context that the purpose of this study is to examine the links between the meanings of bereavement for widows and the types and sources of social support sought. This deepens the understanding of the reasons for the success or failure of service encounters and thus contributes to consumer well-being. Design/methodology/approach A qualitative study was carried out to gain more insight into this issue. A total of 24 in-depth interviews were conducted with French widows 59 years of age and older. To fully understand the diversity of bereavement experiences, the authors examined the following factors: life trajectory, life, as the spouse’s/partner’s death, support received and/or solicited and the success or failure of service encounters. Findings The findings suggest that bereavement experiences hold different meanings related to the types and sources of the preferred support. The following six classes were identified: dealing with administrative and financial issues, maintaining parental roles, enduring the memories of the circumstances of the spouse’s/partner’s death, reorganizing daily life, facing the loneliness of widowhood and expressing the affects of bereavement. These classes help to identify the conditions for the success or failure of service encounters. Originality/value The following two avenues emerge that contribute to the well-being of widows: “loss-oriented” and “restoration-oriented” bereavement classes of meanings. The former is embodied by widows primarily seeking “nurturant support” who expect self-oriented and relationship-focused service behaviour on the part of service providers, and the latter by widows primarily seeking “action-facilitating” support who expect “task-oriented” service behaviour from service providers. These results should allow service providers to be aware of when to prioritize the task, the self and/or the relationship, to provide a successful service encounter for consumers of bereavement services
A Multicenter Phase II Study of Pazopanib in Patients with Unresectable Dermatofibrosarcoma Protuberans
No full textInternational audienceDermatofibrosarcoma protuberans (DFSP) is a soft-tissue sarcoma characterized by a high risk of local infiltration. The identification of the COL1A1-PDGFB t(17;22) translocation activating the PDGF pathway led to the use of imatinib in unresectable DFSP, with a response rate of 36-80%. Pazopanib is a multitarget tyrosine kinase inhibitor approved for soft-tissue sarcomas. We conducted a phase II study of patients with unresectable DFSP to evaluate the efficacy and safety of pazopanib. Patients received 800 mg of pazopanib daily. The primary endpoint was the objective response rate defined as the reduction of the largest diameter of the tumor by ≥30% at 6 months or at surgery. A total of 23 patients, including one pretreated with imatinib, were enrolled. With a median follow-up of 6.2 months (interquartile range = 5.6-7.8 months), five patients (22%, 95% confidence interval = 7-22%) had a partial response to pazopanib. The best objective response rate was 30% (95% confidence interval = 13-53%) using Response Evaluation Criteria in Solid Tumors. One patient with metastatic DFSP previously treated with imatinib died after 2.4 months. Nine patients (39%) discontinued the treatment owing to adverse events. Pharmacodynamics analyses of tumor samples were conducted: the enrichment of EGF and the EGFR-associated gene panel was associated with resistance, suggesting that EGFR-targeted therapies could be a therapeutic option to explore in DFSP. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01059656
Determination of the Thresholds in the Split-Step Wavelet Method to Assess Accuracy for Long-Range Propagation
No full textInternational audienc
On damage regularity defect nucleation modelling
No full textInternational audienceThe purpose of this article is to model defect nucleation. The defect is considered as a small volume which evolves as a damaged zone. The damage is described by a transition zone which can be sharp or continuous. In the first case, discontinuities occur and the initiation of defect is based on bifurcation of an equilibrium state. When the transition is continuous, the initiation of the defect is continuous.The analysis is based on considering different models of damage, depending on the regularity imposed on mechanical field. For each model, the presence of discontinuities on mechanical fields is investigated. Consequences of each model on defect nucleation are illustrated on particular structures: bars under extension and spheres under radial loading
Galerkin force model for transient and post-transient dynamics of the fluidic pinball
No full textInternational audienceWe propose an aerodynamic force model associated with a Galerkin model for the unforced fluidic pinball, the two-dimensional flow around three equal cylinders with one radius distance to each other. The starting point is a Galerkin model of a bluff-body flow. The force on this body is derived as a constant-linear-quadratic function of the mode amplitudes from first principles following the pioneering work of Noca (On the evaluation of time-dependent fluid-dynamic forces on bluff bodies. PhD thesis, California Institute of Technology, 1997), Noca et al. (J. Fluids Struct., vol. 13, issue 5, 1999, pp. 551–578) and Liang & Dong (Virtual force measurement of POD modes for a flat plate in low Reynolds number flows. AIAA Paper 2014-0054). The force model is simplified for the mean-field model of the unforced fluidic pinball (Deng et al., J. Fluid Mech., vol. 884, 2020, p. A37) using symmetry properties and sparse calibration. The model is successfully applied to transient and post-transient dynamics in different Reynolds number regimes: the periodic vortex shedding after the Hopf bifurcation and the asymmetric vortex shedding after the pitchfork bifurcation comprising six different Navier–Stokes solutions. We foresee many applications of the Galerkin force model for other bluff bodies and flow control
Grounding an Ecological Theory of Artificial Intelligence in Human Evolution
No full textInternational audienceRecent advances in Artificial Intelligence (AI) have revived the quest for agents able to acquire an open-ended repertoire of skills. Although this ability is fundamentally related to the characteristics of human intelligence, research in this field rarely considers the processes and ecological conditions that may have guided the emergence of complex cognitive capacities during the evolution of the species. Research in Human Behavioral Ecology (HBE) seeks to understand how the behaviors characterizing human nature can be conceived as adaptive responses to major changes in our ecological niche. In this paper, we propose a framework highlighting the role of environmental complexity in open-ended skill acquisition, grounded in major hypotheses from HBE and recent contributions in Reinforcement learning (RL). We use this framework to highlight fundamental links between the two disciplines, as well as to identify feedback loops that bootstrap ecological complexity and create promising research directions for AI researchers. We also present our first steps towards designing a simulation environment that implements the climate dynamics necessary for studying key HBE hypotheses relating environmental complexity to skill acquisition
