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Do Carbon Offsets Offset Carbon?
No full textInternational audienceWe develop and implement a new method for identifying wasted subsidies and use it to provide systematic evidence of the misallocation of carbon offsets in the Clean Development Mechanism—the world's largest carbon offset program. Using newly constructed data on the locations and characteristics of over 1,000 wind farms in India, we estimate that at least 52 percent of approved carbon offsets were allocated to projects that would very likely have been built anyway. We estimate that the sale of these offsets to regulated polluters resulted in substantially higher global carbon dioxide emissions.(JEL H23, O13, Q42, Q54, Q58
Self-supervised learning to predict intrahepatic cholangiocarcinoma transcriptomic classes on routine histology
No full textABSTRACT Objective The transcriptomic classification of intrahepatic cholangiocarcinomas (iCCA) has been recently refined from two to five classes, associated with pathological features, targetable genetic alterations and survival. Despite its prognostic and therapeutic value, the classification is not routinely used in the clinic because of technical limitations, including insufficient tissue material or the cost of molecular analyses. Here, we assessed a self-supervised learning (SSL) model for predicting iCCA transcriptomic classes on whole-slide digital histological images (WSIs) Design Transcriptomic classes defined from RNAseq data were available for all samples. The SSL method, called Giga-SSL, was used to train our model on a discovery set of 766 biopsy slides (n=137 cases) and surgical samples (n=109 cases) from 246 patients in a five-fold cross-validation scheme. The model was validated in The Cancer Genome Atlas (TCGA) (n= 29) and a French external validation set (n=32). Results Our model showed good to very good performance in predicting the four most frequent transcriptomic class in the discovery set (area under the curve [AUC]: 0.63-0.84), especially for the hepatic stem-like class (37% of cases, AUC 0.84). The model performed equally well in predicting these four transcriptomic classes in the two validation sets, with AUCs ranging from 0.76 to 0.80 in the TCGA set and 0.62 to 0.92 in the French external set. Conclusion We developed and validated an SSL-based model for predicting iCCA transcriptomic classes on routine histological slides of biopsy and surgical samples, which may impact iCCA management by predicting prognosis and guiding the treatment strategy
Allemagne-France 1830-1930: agir pour une souveraineté conceptive - penser, enseigner et organiser la conception collective dans les formations des ingénieurs et designers.
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Decarbonisation modelling for key industrial sectors focusing on process changes in a cost-optimised pathway
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Convergence of bipartite open quantum systems stabilized by reservoir engineering
No full text33 pages. Comments welcomeInternational audienceWe study a generic family of Lindblad master equations modeling bipartite open quantum systems, where one tries to stabilize a quantum system by carefully designing its interaction with another, dissipative, quantum system - a strategy known as quantum reservoir engineering. We provide sufficient conditions for convergence of the considered Lindblad equations; our setting accommodates the case where steady states are not unique but rather supported on a given subspace of the underlying Hilbert space. We apply our result to a Lindblad master equation proposed for the stabilization of so-called cat qubits, a system that received considerable attention in recent years due to its potential applications in quantum information processing
Borehole description of the valley bottoms alluvium in the Seine catchment
No full textDataset presents a total of 4817 boreholes that intersect the alluvium at the bottom of the main valleys within the Seine River catchmentThis dataset presents a total of 4817 boreholes that intersect the alluvium at the bottom of the main valleys within the Seine River catchment, mapped based on geological maps at 1:50 000 scale (Pomerol and Monciardini, 1992; Janjou, 2004; Quesnel et al., 2008). The boreholes were extracted from (i) the BSS (Base du Sol et Sous-sol) database available on the French Geological Survey (BRGM) website (http://infoterre.brgm.fr/) and (ii) data available in the literature (Lefebvre et al., 1974; Pomerol and Morciandini, 1992; Krier, 2004; Chourio- Camacho et al., 2024). Each borehole was manually analyzed to ensure consistency between data. This dataset contains the following information: (i) geographic position of each borehole using both WGS84 and the RGF Lambert 1993 projection, (ii) elevation at the bedrock-alluvium interface, (iii) a description of the alluvium such as total alluvial thickness, alluvial facies description, depth and thickness of each individual alluvial facies, (iv) bedrock characteristics such as lithology, geological formation and age, (v) valley location (Chourio- Camacho, 2024) and (vi) total of facies for each borehole, date of drilling, the data provider and the link to data. Our dataset has numerous applications in geomorphology and hydrology. It allows estimating the geometry of the alluvial infill and reconstituting the geometry of the top of the bedrock substrate or quantifying the sediment volume storage along the valley bottoms of the Seine catchment
Relationship between polymorphic structures and magnetic properties of La2−xA′ Ni7 compounds (A′ = Sm, Gd)
No full textInternational audienceA2Ni7 compounds (A = rare earth) are of interest for their fundamental structural and magnetic properties such as weak itinerant magnets when A = Y and La. In this study, the crystal structure and magnetic properties of La2-xA'xNi7 compounds with magnetic rare earth elements (A' = Sm, Gd) have been investigated combining X-ray powder diffraction and magnetic measurements. These intergrowth compounds crystallize in a mixture of 2H hexagonal (Ce2Ni7-type) and 3R rhombohedral (Gd2Co7-type) polymorphic structures which are related to the stacking of [AB5] and [A2B4] subunits along the c-axis. The average cell volume decreases linearly versus A' content, whereas the c/a ratio reaches a minimum at x = 1, due to geometric constraints upon A' for La substitution between the two different subunits. The magnetic properties strongly depend on the structure type and the A' content. Hexagonal La2Ni7 is a weak antiferromagnet (wAFM) at low field and temperature and undergoes metamagnetic transitions towards weak ferromagnetic state (wFM) under applied field. Under an applied field of 0.1 T, La2-xA'xNi7 intermetallic compounds display two different transition temperatures T1 and T2 that both increase with x. T1 is associated with a wFM-wAFM transition in the 2H phase for A'= Sm, whereas T2 is related to the Curie temperature of both 2H and 3R phases. A metamagnetic behaviour is observed between T1 and T2 with transition field µ0HTrans between 2 and 3.5 T for compounds with A' = Sm. The La2-xSmxNi7 compounds (x > 0) behave as hard magnets with a large coercive field µ0HC at low temperature (µ0HC > 9 T at 5 K for x = 2), whereas the La2-xGdxNi7 compounds (x > 0) are soft ferrimagnets with a linear increase of the saturation magnetization versus Gd content
Construction of Data Sequence for Model Order Reduction in Thermomechanical Modeling of DED Additive Manufacturing
No full textInternational audienceABSTRACT Reduced order modeling (ROM) is applied to the finite element thermo‐mechanical simulation of metal additive manufacturing at part scale. This is a significant challenge because of the continuously evolving computational domain, on which a local reduced basis is required to apply the projection‐based ROM. In this paper, ROM is applied to the mechanical resolution, which is much more time‐consuming than the thermal one. Considering the modeling of DED processes (directed energy deposition), it is proposed to organize the training set of simulation snapshots according to an energy deposition length that represents the progress of the process. The full‐order model consists of a transient thermomechanical model modified by use of the previously developed Inherent Strain Rate method. When applying the projection‐based ROM to this full‐order model, the constructed data sequence enables the design a local ROM depending on the energy deposition length and process parameters. The approach, in its present state, is limited to constructions with a constant transverse geometry and a constant set of process parameters. The simulation of the DED construction of a turbine blade mock‐up, made of thirty layers with interlayer dwell times, revealed a computational speedup of about 100
Tuning morphology and properties of cellulose-based aerogels and xerogels by the introduction of tosyl moieties
No full textInternational audienceAerogels are nanostructured materials of high porosity and high specific surface area. While the first cellulose II aerogels were made about 20 years ago, practically nothing is known about the influence of the degree of substitution of cellulose ethers and esters on aerogel properties. Model hydrophobic moieties (here, tosyl) were introduced on the cellulose backbone by homogeneous derivatisation with the goal to investigate the influence of the degree of substitution (DS) on the morphology and properties of aerogels and xerogels. The materials were produced via the dissolution-coagulation route followed by drying with supercritical (sc) CO2 (named aerogels) or low-vacuum evaporation (named xerogels). Reference materials were made from microcrystalline cellulose (MCC). The goal was to investigate how the introduction of a bulky tosyl group influences the self-assembly of polymer chains during non-solvent-induced phase separation, and to assess the impact of the DS on aerogel and xerogel properties. The DS of tosyl cellulose was varied from 0.22 to 1.26, and different non-solvents (water, ethanol, acetone) were used to test their influence on the materials’ properties. Aerogel densities ranged from 0.04 to 0.28 g/cm3, while xerogel densities were between 0.09 and 1.52 g/cm3. Drying only with sc CO2 resulted in materials with high specific surface area, up to 360 m2/g. The increase in DS resulted in materials with a coarser morphology and a significant rise in hydrophobicity, as evidenced by a water contact angle reaching 130°