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Xavier Dupont de Ligonnès : archétype d'un « évaporé à la française » ?
No full textPar-delà l'horreur d'un crime, la fuite de Xavier Dupont de Ligonnès intrigue, mais elle ne relève ni de la honte ni du renoncement. À rebours des johatsu japonais, qui s'évaporent du jour au lendemain sans laisser de trace physique ou numérique, cette fuite semble pensée comme un geste de toute-puissance, entre scénarisation minutieuse et contrôle absolu sur les évènements. Il s'agit sans conteste d'un mystère persistant qui continue d'alimenter interrogations, récits et spéculations
A Panoply of Consequences? Remedies and Reparations in the ICJ’s Climate Opinion
No full texthttps://verfassungsblog.de/a-panoply-of-consequences/The International Court of Justice (ICJ)’s recent advisory opinion on climate change represents a pivotal moment in the evolution of international climate law. By affirming that States can incur legal responsibility for failing to reduce greenhouse gas (GHG) emissions, the ICJ brought long-standing principles of State responsibility into sharper focus within the climate context. Among the opinion’s most significant – but underexplored – aspects is its treatment of reparations and remedies. This blog post unpacks the legal consequences outlined by the ICJ, examining what the opinion says and doesn’t say about how climate-related harm should be remedied. At the heart of this analysis lies a central question: can the affirmation of legal responsibility without clear guidance on reparation design meaningfully advance climate justice? Similarly to our analysis of how the IACtHR dealt with reparations, the ICJ touched on essential parts, but could have gone further
Prévenir plutôt que guérir : les innovations de l’Accord de Paris en matière de suivi du respect des engagements et de prévention des différends
No full textInternational audienceThe lack of sufficient enforcement mechanisms and the absence of sanctions in the event of non-compliance have long contributed to systemic difficulties in implementing international environmental law, including in the field of climate change. Unlike the United Nations Framework Convention on Climate Change and the Kyoto Protocol, whose dispute settlement and compliance mechanisms have been criticized as too rigid, the Parties to the Paris Agreement have adopted an incentive-based, non-punitive and transparent approach to the prevention and settlement of disputes. The Paris Agreement establishes a committee of experts focused on facilitation within a triad of flexible mechanisms centered on transparency and designed to support the Parties in fulfilling their obligations, even in the absence of a dispute or identified breach. Unlike its predecessors, it does not create a mechanism for settling disputes between the Parties, nor sanctions in the event of non-compliance. Moreover, a Party cannot initiate proceedings before the Implementation and Compliance Committee with respect to another Party. After highlighting the procedural and substantive innovations introduced by the Paris Agreement in terms of compliance monitoring and dispute prevention, this study will analyze whether these novel but lacking teeth mechanisms are likely to remedy the structural and longstanding challenges in the implementation of international climate change law.Le droit international de l’environnement, y compris dans le domaine des changements climatiques, se caractérise par des difficultés de mise en oeuvre, qui sont en partie causées par la faiblesse du contrôle du respect des obligations et l’absence de sanction en cas de non-respect. À rebours de la Convention-cadre des Nations Unies sur les changements climatiques et le Protocole de Kyoto, dont les mécanismes de règlements des différends et de contrôle du respect des engagements avaient été critiqués pour leur trop grande rigidité, les Parties à l’Accord de Paris ont adopté une approche essentiellement incitative, non punitive, et fondée sur la transparence. L’Accord de Paris établit un comité d’experts axé sur la facilitation, au sein d’un triptyque de mécanismes souples centrés sur la transparence et destinés à accompagner les Parties dans l’exécution de leurs obligations y compris en l’absence de litige ou de manquement constaté. Au contraire de ses prédécesseurs, il n’instaure ni mécanisme de règlement des différends entre Parties ni sanction en cas de non-respect. Les Parties se voient d’ailleurs privées de la possibilité d’amorcer une procédure de contrôle à l’encontre d’une autre Partie devant le Comité de mise en oeuvre et de conformité de l’Accord de Paris. Après une mise en lumière des innovations procédurales et substantielles introduites par l’Accord de Paris en matière de suivi de la mise en oeuvre et de prévention des différends, la présente étude analysera si les mécanismes novateurs qu’il instaure sont susceptibles de remédier aux difficultés structurelles de mise en oeuvre du droit international du climat, en l’absence d’un méca¬nisme traditionnel de règlement des différends entre les Parties
Magnetic Phases and Zone-Folded Phonons in a Frustrated van der Waals Magnet
No full textInternational audience2D magnetic materials have attracted extensive research interest due to their potential application in nanospintronics, optospintronics, and in magnonics. Ferromagnetic as well as antiferromagnetic layered materials have been demonstrated and successfully inserted into van der Waals heterostructures. However, the effects of magnetic frustration in van der Waals materials and the possibilities offered by spin configurations characterized by nonlinear spin arrangements have not been fully considered yet. Herein, we establish the magnetic phase diagram of bulk CrOCl, a frustrated van der Waals magnet, using magnetization and magneto-optical spectroscopy techniques. In particular, we use the magnetic superstructures relative to the crystallographic unit cell and the associated rich zone-folded phonon series to describe the magnetic field induced phases. Theoretical calculations taking into account the competing nearest neighbors magnetic exchange interactions provide a unique insight into the lattice vibrations of this class of magnetic system. This study expands the scope of 2D magnetic materials and provides a methodology to characterize frustrated van der Waals magnets
The Lifetime of Sequential Memory Traces in the Absence of Language
No full textInternational audienceStatistical learning allows us to implicitly create memory traces of recurring sequential patterns appearing in our environment. Here, we study the dynamics of how these sequential memory traces develop in a species of nonhuman primates (i.e., Guinea baboons, Papio papio ) that, unlike humans, cannot use language and verbal recoding strategies to strengthen these memory traces. We test a group of Guinea baboons in a Hebb visuo‐motor pointing task in which a target sequence is repeated with random sequences inserted between repetitions. In this study, we systematically manipulate the interval between two repetitions of the target sequence by varying the number of interposed random sequences. We found that baboons can learn repeated visuo‐motor sequences, even when the repetitions are separated by six random sequences. Our results also suggest that the learning curve of the target sequence best fits a logarithmic function. The present study, therefore, provides a quantitative assessment of the development of a sequential memory trace as a function of repetition spacing and without the use of verbal recoding strategies
Screen-Printed 1 × 4 Quasi-Yagi-Uda Antenna Array on Highly Flexible Transparent Substrate for the Emerging 5G Applications
No full textInternational audienceIn the Internet of Things (IoT) era, the demand for cost-effective, flexible, wearable antennas and circuits has been growing. Accordingly, screen-printing techniques are becoming more popular due to their lower costs and high-volume manufacturing. This paper presents and investigates a full-screen-printed 1 × 4 Quasi-Yagi-Uda antenna array on a high-transparency flexible Zeonor thin-film substrate for emerging 26 GHz band (24.25–27.55 GHz) 5G applications. As part of this study, screen-printing implementation rules are developed by properly managing ink layer thickness on a transparent flexible Zeonor thin-film dielectric to achieve a decent antenna array performance. In addition, a screen-printing repeatability study has been carried out through a performance comparison of 24 antenna array samples manufactured by our research partner from CEA-Liten Grenoble. Despite the challenging antenna array screen printing at higher frequencies, the measured results show a good antenna performance as anticipated from the traditional subtractive printed circuit board (PCB) manufacturing process using standard substrates. It shows a wide-band matched input impedance from 22–28 GHz (i.e., 23% of relative band-width) and a maximum realized gain of 12.8 dB at 27 GHz
Euclid preparation. Full-shape modelling of 2-point and 3-point correlation functions in real space
No full textInternational audienceWe investigate the accuracy and range of validity of the perturbative model for the 2-point (2PCF) and 3-point (3PCF) correlation functions in real space in view of the forthcoming analysis of the Euclid mission spectroscopic sample. We take advantage of clustering measurements from four snapshots of the Flagship I N-body simulations at z = {0.9, 1.2, 1.5, 1.8}, which mimic the expected galaxy population in the ideal case of absence of observational effects such as purity and completeness. For the 3PCF we consider all available triangle configurations given a minimal separation. First, we assess the model performance by fixing the cosmological parameters and evaluating the goodness-of-fit provided by the perturbative bias expansion in the joint analysis of the two statistics, finding overall agreement with the data down to separations of 20 Mpc/h. Subsequently, we build on the state-of-the-art and extend the analysis to include the dependence on three cosmological parameters: the amplitude of scalar perturbations As, the matter density ωcdm and the Hubble parameter h. To achieve this goal, we develop an emulator capable of generating fast and robust modelling predictions for the two summary statistics, allowing efficient sampling of the joint likelihood function. We therefore present the first joint full-shape analysis of the real-space 2PCF and 3PCF, testing the consistency and constraining power of the perturbative model across both probes, and assessing its performance in a combined likelihood framework. We explore possible systematic uncertainties induced by the perturbative model at small scales finding an optimal scale cut of rmin = 30 Mpc/h for the 3PCF, when imposing an additional limitation on nearly isosceles triangular configurations included in the data vector. This work is part of a Euclid Preparation series validating theoretical models for galaxy clustering
Emergence of cosmic structure from Planckian discreteness
No full textInternational audienceIn the standard inflationary paradigm the inhomogeneities observed in the CMB arise from quantum fluctuations of an initially homogeneous and isotropic vacuum state. This picture suffers from two well-known weaknesses. First, it assumes that quantum field theory remains valid at trans-Planckian scales, without modifications from quantum gravity. Second, it necessitates a quantum-to-classical transition in which fluctuations of a homogeneous quantum state become the classical inhomogeneities seen in the CMB. Recently, an alternative paradigm has been proposed in which such inhomogeneities are present from the very beginning, emerging from the assumed discreteness of spacetime at the Planck scale predicted by certain approaches to quantum gravity. Within this framework, scale-invariant scalar perturbations are generated naturally, without relying on trans-Planckian assumptions or invoking a quantum-to-classical transition. Specifically, inhomogeneities in the quantum state at the Planck scale propagate into semiclassical inhomogeneities on CMB scales. Here, we extend the aforementioned proposal to the most realistic case of a quasi-de Sitter expansion; in particular, we compute the scalar perturbation spectrum as a function of the slow-roll parameters, systematically encoded through the Hubble flow functions