Archives ouvertes de Paris-Saclay
Not a member yet
272730 research outputs found
Sort by
Black Bread, White Bread, and Carbon Lock-in: Shifting Economic Views of the Belgian Coal Industry (1840s-1930s)
No full textInternational audienceBelgium experienced early industrialisation based on coal. Economists soon realised that these resources were essential for development, with coal being referred to as the “black bread” of the industry. Gradually, attention turned to the mining sector as a source of social stability, political empowerment, and national cohesion. Coal became a source of “white bread.” This article examines these evolving views from the 1840s to the 1930s, arguing that Belgian society experienced multidimensional carbon lock-in. It also analyses early Belgian theoretical contributions to the economics of exhaustible resources
Dark Energy Survey Year 6 Results: Cosmological Constraints from Galaxy Clustering and Weak Lensing
No full textInternational audienceWe present cosmology results combining galaxy clustering and weak gravitational lensing measured in the full six years (Y6) of observations by the Dark Energy Survey (DES) covering 5000 deg. We perform a large-scale structure analysis using three two-point correlation functions (32pt): (i) cosmic shear from 140 million source galaxy shapes, (ii) galaxy clustering of 9 million lens galaxy positions, and (iii) galaxy-galaxy lensing from their cross-correlation. We model the data in flat CDM and CDM cosmologies. The combined analysis yields and matter density in CDM (68% CL), where is the clustering amplitude. These constraints show a (full-space) parameter difference of 1.8 from a combination of cosmic microwave background (CMB) primary anisotropy datasets from Planck 2018, ACT-DR6, and SPT-3G DR1. Projected only into the difference is . In CDM the Y6 32pt results yield , , and dark energy equation-of-state parameter . For the first time, we combine all DES dark-energy probes: 32pt, SNe Ia, BAO and Clusters. In CDM this combination yields a parameter difference from the CMB. When combining DES 32pt with other low-redshift datasets (DESI DR2 BAO, DES SNe Ia, SPT clusters), we find a 2.3 parameter difference with CMB. A joint fit of Y6 32pt, CMB, and those low-redshift datasets produces the tightest CDM constraints to date: , , , and eV (95% CL). In CDM, this combination yields
ROI-NeRFs: Hi-Fi Visualization of Objects of Interest within a Scene by NeRFs Composition
No full textInternational audienceEfficient and accurate 3D reconstruction is crucial for cultural heritage applications. This study addresses the challenge of visualizing objects in complex scenes at high levels of detail (LOD) using Neural Radiance Fields (NeRFs), improving visual fidelity for selected objects while maintaining computational efficiency. The proposed ROI-NeRFs framework divides the scene into a Scene NeRF, capturing the overall scene at moderate detail, and multiple Region Of Interest (ROI) NeRFs, focusing on user-defined objects. An object-focused camera selection module automatically groups relevant cameras for each NeRF during the decomposition phase. In contrast, a Ray-level Compositional Rendering technique in the composition phase integrates Scene and ROI NeRFs for simultaneous multi-object rendering. Experiments on two real-world datasets, including a complex eighteenth-century cultural heritage room, demonstrate superior performance over baseline methods, enhancing LOD in object regions, minimizing artifacts, and maintaining efficient inference. INTRODUCTION3D reconstruction of cultural heritage sites is essential for creating digital twins used in archiving, conservation [Kong and Hucks, 2023], archaeology [Haibt, 2024], and interactive museum exhibitions [Liu and Chang, 2024].Neural Radiance Field (NeRF) [Mildenhall et al., 2021] has emerged as a powerful alternative for novel view synthesis (NVS) with unprecedented image quality. NeRF learns scenes as continuous fields of volume density and view-dependent color using MLPs, achieving photorealistic rendering through differentiable volume rendering. However, most NeRF-based methods train a single model on all images of a scene, yielding renderings with a uniform level of detail (LOD). In large-scale scenes, this fixed resolution might lead to poor-quality when viewing close-up specific objects or regions of interest (ROI), while increasing detail globally would incur prohibitive computational costs.</div
What shapes a livable city? Subjective and objective determinants of city satisfaction in Romania
No full textInternational audienceThis article examines urban quality of life in 41 Romanian cities by combining survey evidence from the 2020 Urban Barometer (N = 13,380) with a spatially detailed Quality of Life Index (QOLI) derived from OpenStreetMap and census data. Using hierarchical logistic regression, we assess how individual perceptions and city-level conditions shape city satisfaction. Results show that facilities and services, environmental quality, and governance contribute positively to satisfaction, while perceptions of trust and safety are among the strongest predictors. In contrast, the QOLI measuring the objective availability of amenities is negatively associated with satisfaction, indicating that infrastructure provision alone does not ensure well-being. City size is positively related to satisfaction, whereas economic indicators such as unemployment and aggregate turnover per population have little explanatory power. The study shows that urban well-being depends less on material provision and more on governance, trust, and residents' expectations, with implications for cities in Central and Eastern Europe where historical legacies and uneven development continue to shape urban experiences
Response to Leboyer et al., 2026 - refers to: Advocacy by nonprofit scientific institutions needs to be evidence-based: a case study
No full textInternational audienc
Cosmological analysis of the DESI DR1 Lyman alpha 1D power spectrum
No full textInternational audienceWe present the cosmological analysis of the one-dimensional Lyman- flux power spectrum from the first data release of the Dark Energy Spectroscopic Instrument (DESI). We capture the dependence of the signal on cosmology and intergalactic medium physics using an emulator trained on a cosmological suite of hydrodynamical simulations, and we correct its predictions for the impact of astrophysical contaminants and systematics, many of these not considered in previous analyses. We employ this framework to constrain the amplitude and logarithmic slope of the linear matter power spectrum at and redshift , obtaining and . The robustness of these constraints is validated through the analysis of mocks and a large number of alternative data analysis variations, with cosmological parameters kept blinded throughout the validation process. We then combine our results with constraints from DESI BAO and temperature, polarization, and lensing measurements from Planck, ACT, and SPT-3G to set constraints on CDM extensions. While our measurements do not significantly tighten the limits on the sum of neutrino masses from the combination of these probes, they sharpen the constraints on the effective number of relativistic species, , the running of the spectral index, , and the running of the running, , by a factor of 1.18, 1.27, and 1.90, respectively. We conclude by outlining the improvements needed to fully reach the level of confidence implied by these uncertainties
Role of the symmetry energy on hybrid stars
No full textInternational audienceThe impact of the symmetry energy on the properties of compact stars is analyzed considering constraints from nuclear physics and astrophysics. A compact star can be a neutron star composed only of nuclear matter or a hybrid star with a quark core. Two typical models (soft and stiff) are considered for the nuclear equation of state, and for the hybrid one, a parameterized first-order phase transition approach, completed with a linear quark matter equation of state, is implemented. We show that the phase transition reduces the tension between GW170817 and NICER observations, and we illustrate the impact of the symmetry energy for the understanding of the nature of the binary system in GW170817. We also confirm our previous findings that the GW170817 waveform is best described as a binary HS with a low-density onset of stiff quark matter. This could also be interpreted as a quarkyonic cross-over
Recurrent penile and oral aphthosis revealing an LGL T-cell lymphoproliferative disorder
No full textInternational audienceDear Editor, Large granular T lymphocyte (LGL T-cell) leukaemias are rare and often asymptomatic, which makes diagnosis difficult. We present a patient with colchicine-induced neutropenia, resulting from the treatment of bipolar aphthosis, which led to the identification of an LGL T-cell lymphoproliferative disorder.A 26-year-old man with no previous medical history presented with recurrent painful ulcerations of the glans penis over the previous 2 years (Figure 1a). These lesions were clinically consistent with aphthous ulcers and were accompanied by oedema of the foreskin, which caused intermittent phimosis. He also reported having monthly episodes of oral aphthous ulcers (Figure 1b) from the age of 5 years.Clinical examination and paraclinical tests (including oral and genital mucosal biopsies) revealed no signs of Behçets and no evidence of viral infections (herpes simplex virus, varicella zoster virus, cytomegalovirus or Epstein–Barr virus) or bacterial infections (Treponema pallidum or Chlamydia trachomatis), inflammatory bowel disease, neoplasia or haematological disorders (white blood cell and neutrophil counts were within reference range during aphthous ulcer episodes). A moderate inflammatory syndrome was observed during the flare-ups (C-reactive protein 27 mg L–1)
CKD, nutrition and the brain: How to maintain brain health through nutrition in CKD
No full textInternational audienceChronic kidney disease (CKD) is increasingly recognized not only as a kidney disorder but also as a contributor to cognitive impairment (CI). The kidney and brain share a common vulnerability to uremic toxins, whose accumulation in CKD is exacerbated by gut dysbiosis. These toxins impair the integrity of the blood-brain barrier (BBB), reduce neurogenesis, and promote neuroinflammation. Therefore, maintaining brain health in CKD requires a holistic approach targeting the gut–kidney–brain axis. Nutritional strategies, particularly plant-based diets such as the Mediterranean or dietary approaches to stop hypertension (DASH) diets, have demonstrated benefits for both renal and cerebral outcomes. Because dietary interventions alone may be insufficient, combining nutritional approaches with physical activity and pharmacological strategies, such as Glucagon-Like Peptide-1 (GLP-1) receptor agonists or Sodium Glucose Co-Transporter 2 (SGLT2) inhibitors, may offer synergistic effects. Understanding and modulating the interactions between diet, microbiota, and uremic toxins is essential to preserve cognitive and kidney function in CKD patients, highlighting the need for integrated care