329 results on '"Duteil, P."'
Search Results
2. Mean-field limit of non-exchangeable multi-agent systems over hypergraphs with unbounded rank
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Ayi, Nathalie, Duteil, Nastassia Pouradier, and Poyato, David
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Mathematics - Analysis of PDEs - Abstract
Interacting particle systems are known for their ability to generate large-scale self-organized structures from simple local interaction rules between each agent and its neighbors. In addition to studying their emergent behavior, a main focus of the mathematical community has been concentrated on deriving their large-population limit. In particular, the mean-field limit consists of describing the limit system by its population density in the product space of positions and labels. The strategy to derive such limits is often based on a careful combination of methods ranging from analysis of PDEs and stochastic analysis, to kinetic equations and graph theory. In this article, we focus on a generalization of multi-agent systems that includes higher-order interactions, which has largely captured the attention of the applied community in the last years. In such models, interactions between individuals are no longer assumed to be binary (i.e. between a pair of particles). Instead, individuals are allowed to interact by groups so that a full group jointly generates a non-linear force on any given individual. The underlying graph of connections is then replaced by a hypergraph, which we assume to be dense, but possibly non uniform and of unbounded rank. For the first time in the literature, we show that when the interaction kernels are regular enough, then the mean-field limit is determined by a limiting Vlasov-type equation, where the hypergraph limit is encoded by a so-called UR-hypergraphon (unbounded-rank hypergraphon), and where the resulting mean-field force admits infinitely-many orders of interactions.
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- 2024
3. animal2vec and MeerKAT: A self-supervised transformer for rare-event raw audio input and a large-scale reference dataset for bioacoustics
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Schäfer-Zimmermann, Julian C., Demartsev, Vlad, Averly, Baptiste, Dhanjal-Adams, Kiran, Duteil, Mathieu, Gall, Gabriella, Faiß, Marius, Johnson-Ulrich, Lily, Stowell, Dan, Manser, Marta B., Roch, Marie A., and Strandburg-Peshkin, Ariana
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Computer Science - Sound ,Computer Science - Artificial Intelligence ,Electrical Engineering and Systems Science - Audio and Speech Processing ,Quantitative Biology - Quantitative Methods ,Statistics - Applications - Abstract
Bioacoustic research, vital for understanding animal behavior, conservation, and ecology, faces a monumental challenge: analyzing vast datasets where animal vocalizations are rare. While deep learning techniques are becoming standard, adapting them to bioacoustics remains difficult. We address this with animal2vec, an interpretable large transformer model, and a self-supervised training scheme tailored for sparse and unbalanced bioacoustic data. It learns from unlabeled audio and then refines its understanding with labeled data. Furthermore, we introduce and publicly release MeerKAT: Meerkat Kalahari Audio Transcripts, a dataset of meerkat (Suricata suricatta) vocalizations with millisecond-resolution annotations, the largest labeled dataset on non-human terrestrial mammals currently available. Our model outperforms existing methods on MeerKAT and the publicly available NIPS4Bplus birdsong dataset. Moreover, animal2vec performs well even with limited labeled data (few-shot learning). animal2vec and MeerKAT provide a new reference point for bioacoustic research, enabling scientists to analyze large amounts of data even with scarce ground truth information., Comment: Code available at: https://github.com/livingingroups/animal2vec | Dataset available at: https://doi.org/10.17617/3.0J0DYB
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- 2024
4. An integrative phenotype-structured partial differential equation model for the population dynamics of epithelial-mesenchymal transition
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Guilberteau, Jules, Jain, Paras, Jolly, Mohit Kumar, Duteil, Nastassia Pouradier, and Pouchol, Camille
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Mathematics - Analysis of PDEs - Abstract
Phenotypic heterogeneity along the epithelial-mesenchymal (E-M) axis contributes to cancer metastasis and drug resistance. Recent experimental efforts have collated detailed time-course data on the emergence and dynamics of E-M heterogeneity in a cell population. However, it remains unclear how different possible processes interplay in shaping the dynamics of E-M heterogeneity: a) intracellular regulatory interaction among biomolecules, b) cell division and death, and c) stochastic cell-state transition (biochemical reaction noise and asymmetric cell division). Here, we propose a Cell Population Balance (Partial Differential Equation (PDE)) based model that captures the dynamics of cell population density along the E-M phenotypic axis due to abovementioned multi-scale cellular processes. We demonstrate how population distribution resulting from intracellular regulatory networks driving cell-state transition gets impacted by stochastic fluctuations in E-M regulatory biomolecules, differences in growth rates among cell subpopulations, and initial population distribution. Further, we reveal that a linear dependence of the cell growth rate on the population heterogeneity is sufficient to recapitulate the faster in vivo growth of orthotopic injected heterogeneous E-M subclones reported before experimentally. Overall, our model contributes to the combined understanding of intracellular and cell-population levels dynamics in the emergence of E-M heterogeneity in a cell population.
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- 2023
5. Editorial: Constraining uncertainties in hindcasts and future projections of marine deoxygenation
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Shigemitsu, Masahito, Duteil, Olaf, Ito, Takamitsu, Tjiputra, Jerry, and Eddebbar, Yassir
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Oceanography ,Biological Sciences ,Ecology ,Earth Sciences ,Geology ,deoxygenation ,oxygen minimum zones ,model uncertainty ,ocean biogeochemical model ,climate projection ,climate change ,hindcast - Published
- 2024
6. Graph Limit for Interacting Particle Systems on Weighted Random Graphs
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Ayi, Nathalie and Duteil, Nastassia Pouradier
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Mathematics - Analysis of PDEs - Abstract
In this article, we study the large-population limit of interacting particle systems posed on weighted random graphs. In that aim, we introduce a general framework for the construction of weighted random graphs, generalizing the concept of graphons. We prove that as the number of particles tends to infinity, the finite-dimensional particle system converges in probability to the solution of a deterministic graph-limit equation, in which the graphon prescribing the interaction is given by the first moment of the weighted random graph law. We also study interacting particle systems posed on switching weighted random graphs, which are obtained by resetting the weighted random graph at regular time intervals. We show that these systems converge to the same graph-limit equation, in which the interaction is prescribed by a constant-in-time graphon.
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- 2023
7. Direct current measurements of the SPIDER beam: a comparison to existing beam diagnostics
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Shepherd, A., Patton, T., Pimazzoni, A., Pouradier-Duteil, B., Garola, A. Rigoni, Sartori, E., Ugoletti, M., and Serianni, G.
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Physics - Accelerator Physics ,Physics - Plasma Physics - Abstract
For negative ion beam sources there are several methods of measuring the accelerated beam current, most commonly electrical measurements at the power supply and calorimetric measurements. On SPIDER, the ITER Heating Neutral Beam full-scale beam source prototype, electrical measurements at the acceleration grid power supply (AGPS) are complemented by polarizing the diagnostic calorimeter STRIKE to provide an additional electrical measurement of the accelerated current. This is in addition to the calorimetric measurements provided by STRIKE. These diagnostics give differing measurements of the beam current. Exploiting the reduced number of open apertures on SPIDER a new beam diagnostic has been installed to measure the individual beamlet currents directly. The so called Beamlet Current Monitor (BCM) has been used to measure the current of five beamlets during the most recent SPIDER campaign. This work compares the BCM current to the electrical measurements at the AGPS and STRIKE. The average BCM current agrees well with the STRIKE electrical measurements, indicating that the AGPS overestimates the beam current. The individual beamlets are compared to the STRIKE calorimetric measurements, showing similar current trends with the source parameters.
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- 2023
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8. Emergent constraint on oxygenation of the upper South Eastern Pacific oxygen minimum zone in the twenty-first century
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Almendra, Ivan, Dewitte, Boris, Garçon, Véronique, Muñoz, Praxedes, Parada, Carolina, Montes, Ivonne, Duteil, Olaf, Paulmier, Aurélien, Pizarro, Oscar, Ramos, Marcel, Koeve, Wolfgang, and Oschlies, Andreas
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- 2024
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9. LSD1 inhibition circumvents glucocorticoid-induced muscle wasting of male mice
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Cai, Qingshuang, Sahu, Rajesh, Ueberschlag-Pitiot, Vanessa, Souali-Crespo, Sirine, Charvet, Céline, Silem, Ilyes, Cottard, Félicie, Ye, Tao, Taleb, Fatima, Metzger, Eric, Schuele, Roland, Billas, Isabelle M. L., Laverny, Gilles, Metzger, Daniel, and Duteil, Delphine
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- 2024
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10. Lessons learned after three years of SPIDER operation and the first MITICA integrated tests
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Marcuzzi, D., Toigo, V., Boldrin, M., Chitarin, G., Bello, S. Dal, Grando, L., Luchetta, A., Pasqualotto, R., Pavei, M., Serianni, G., Zanotto, L., Agnello, R., Agostinetti, P., Agostini, M., Aprile, D., Barbisan, M., Battistella, M., Berton, G., Bigi, M., Brombin, M., Candela, V., Candeloro, V., Canton, A., Casagrande, R., Cavallini, C., Cavazzana, R., Cordaro, L., Cruz, N., Palma, M. Dalla, Dan, M., De Lorenzi, A., Delogu, R., De Muri, M., De Nardi, M., Denizeau, S., Fadone, M., Fellin, F., Ferro, A., Gaio, E., Gasparrini, C., Gnesotto, F., Jain, P., La Rosa, A., Lopez-Bruna, D., Lorenzini, R., Maistrello, A., Manduchi, G., Manfrin, S., Marconato, N., Mario, I., Martini, G., Milazzo, R., Patton, T., Peruzzo, S., Pilan, N., Pimazzoni, A., Poggi, C., Pomaro, N., Pouradier-Duteil, B., Recchia, M., Rigoni-Garola, A., Rizzetto, D., Rizzolo, A., Santoro, F., Sartori, E., Segalini, B., Shepherd, A., Siragusa, M., Sonato, P., Sottocornola, A., Spada, E., Spagnolo, S., Spolaore, M., Taliercio, C., Tinti, P., Tomsič, P., Trevisan, L., Ugoletti, M., Valente, M., Valisa, M., Veronese, F., Vignando, M., Zaccaria, P., Zagorski, R., Zaniol, B., Zaupa, M., Zuin, M., Cavenago, M., Boilson, D., Rotti, C., Decamps, H., Geli, F., Sharma, A., Veltri, P., Zacks, J., Simon, M., Paolucci, F., Garbuglia, A., Gutierrez, D., Masiello, A., Mico, G., Labate, C., Readman, P., Bragulat, E., Bailly-Maitre, L., Gomez, G., Kouzmenko, G., Albajar, F., Kashiwagi, M., Tobari, H., Kojima, A., Murayama, M., Hatakeyama, S., Oshita, E., Maejima, T., Shibata, N., Yamashita, Y., Watanabe, K., Singh, N. P., Singh, M. J., Dhola, H., Fantz, U., Heinemann, B., Wimmer, C., Wünderlich, D., Tsumori, K., Croci, G., Gorini, G., Muraro, A., Rebai, M., Tardocchi, M., Giacomelli, L., Rigamonti, D., Taccogna, F., Bruno, D., Rutigliano, M., Longo, S., Deambrosis, S., Miorin, E., Montagner, F., Tonti, A., and Panin, F.
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Physics - Plasma Physics ,Physics - Accelerator Physics - Abstract
ITER envisages the use of two heating neutral beam injectors plus an optional one as part of the auxiliary heating and current drive system. The 16.5 MW expected neutral beam power per injector is several notches higher than worldwide existing facilities. A Neutral Beam Test Facility (NBTF) was established at Consorzio RFX, exploiting the synergy of two test beds, SPIDER and MITICA. SPIDER is dedicated to developing and characterizing large efficient negative ion sources at relevant parameters in ITER-like conditions: source and accelerator located in the same vacuum where the beam propagates, immunity to electromagnetic interferences of multiple radio-frequency (RF) antennas, avoidance of RF-induced discharges on the outside of the source. Three years of experiments on SPIDER have addressed to the necessary design modifications to enable full performances. The source is presently under a long shut-down phase to incorporate learnings from the experimental campaign. Parallelly, developments on MITICA, the full-scale prototype of the ITER NBI featuring a 1 MV accelerator and ion neutralization, are underway including manufacturing of in-vessel components, while power supplies and auxiliary plants are already under final testing and commissioning. Integration, commissioning and tests of the 1MV power supplies are essential for this first-of-kind system, unparalleled both in research and industry field. The integrated test to confirm 1MV output by combining invertor systems, DC generators and transmission lines extracted errors/accidents in some components. To realize a concrete system for ITER, solutions for the repair and the improvement of the system were developed. Hence, NBTF is emerging as a necessary facility, due to the large gap with existing injectors, effectively dedicated to identify issues and find solutions to enable successful ITER NBI operations in a time bound fashion.
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- 2023
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11. Optimizing Floors in First Price Auctions: an Empirical Study of Yahoo Advertising
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Alcobendas, Miguel, Ji, Jonathan, Gokulakannan, Hemakumar, Wami, Dawit, Kapchits, Boris, Duteil, Emilien Pouradier, Satow, Korby, Roman, Maria Rosario Levy, Diaz, Oriol, Diaz Jr., Amado A., and Kavoori, Rabi
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Computer Science - Computer Science and Game Theory ,Computer Science - Machine Learning - Abstract
Floors (also known as reserve prices) help publishers to increase the expected revenue of their ad space, which is usually sold via auctions. Floors are defined as the minimum bid that a seller (it can be a publisher or an ad exchange) is willing to accept for the inventory opportunity. In this paper, we present a model to set floors in first price auctions, and discuss the impact of its implementation on Yahoo sites. The model captures important characteristics of the online advertising industry. For instance, some bidders impose restrictions on how ad exchanges can handle data from bidders, conditioning the model choice to set reserve prices. Our solution induces bidders to change their bidding behavior as a response to the floors enclosed in the bid request, helping online publishers to increase their ad revenue. The outlined methodology has been implemented at Yahoo with remarkable results. The annualized incremental revenue is estimated at +1.3% on Yahoo display inventory, and +2.5% on video ad inventory. These are non-negligible numbers in the multi-million Yahoo ad business.
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- 2023
12. Emergent constraint on oxygenation of the upper South Eastern Pacific oxygen minimum zone in the twenty-first century
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Ivan Almendra, Boris Dewitte, Véronique Garçon, Praxedes Muñoz, Carolina Parada, Ivonne Montes, Olaf Duteil, Aurélien Paulmier, Oscar Pizarro, Marcel Ramos, Wolfgang Koeve, and Andreas Oschlies
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Geology ,QE1-996.5 ,Environmental sciences ,GE1-350 - Abstract
Abstract As a consequence of on-going global warming, the ocean is losing oxygen, which has implications not only in terms of marine resources management and food supply but also in terms of the potentially important feedback on the global carbon cycle and climate. Of particular scrutiny are the extended zones of already low levels of oxygen called the oxygen minimum zones (OMZs) embedded in the subsurface waters of the productive Eastern Boundary Upwelling Systems (EBUS). These OMZs are currently diversely simulated by state-of-the-art Earth System Models (ESM) hampering a reliable projection of ocean deoxygenation on marine ecosystem services in these regions. Here we focus on the most emblematic EBUS OMZs of the planet, that of the South Eastern Pacific (SEP), which is under the direct influence of the El Niño Southern Oscillation (ENSO), the main climate mode on interannual timescales at global scale. We show that, despite the low consensus among ESM long-term projections of oxygen levels, the sensitivity of the depth of the upper margin (oxycline) of the SEP OMZ to El Niño events in an ensemble of ESMs can be used as a predictor of its long-term trend, which establishes an emergent constraint for the SEP OMZ. Because the oxycline along the coast of Peru and Chile deepens during El Niño events, the upper bound of the SEP OMZ is thus likely to deepen in the future climate, therefore oxygenating the SEP OMZ. This has implications not only for understanding the nitrogen and carbon cycles at global scale but also for designing adaptation strategies for regional upper-ocean ecosystem services.
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- 2024
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13. Long-time behaviour of an advection-selection equation
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Guilberteau, Jules, Pouchol, Camille, and Duteil, Nastassia Pouradier
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Mathematics - Analysis of PDEs - Abstract
We study the long-time behaviour of the advection-selection equation $$\partial_tn(t,x)+\nabla \cdot \left(f(x)n(t,x)\right)=\left(r(x)-\rho(t)\right)n(t,x),\quad \rho(t)=\int_{\mathbb{R}^d}{n(t,x)dx}\quad t\geq 0, \; x\in \mathbb{R}^d,$$ with an initial condition $n(0, \cdot)=n^0$. In the field of adaptive dynamics, this equation typically describes the evolution of a phenotype-structured population over time. In this case, $x\mapsto n(t,x)$ represents the density of the population characterised by a phenotypic trait $x$, the advection term `$\nabla \cdot \left(f(x)n(t,x)\right)$' a cell differentiation phenomenon driving the individuals toward specific regions, and the selection term `$\left(r(x)-\rho(t)\right)n(t,x)$' the growth of the population, which is of logistic type through the total population size $\rho(t)=\int_{\mathbb{R}^d}{n(t,x)dx}$. In the one-dimensional case $x\in \mathbb{R}$, we prove that the solution to this equation can either converge to a weighted Dirac mass or to a function in $L^1$. Depending on the parameters $n^0$, $f$ and $r$, we determine which of these two regimes of convergence occurs, and we specify the weight and the point where the Dirac mass is supported, or the expression of the $L^1$-function which is reached.
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- 2023
14. Continuous pulse advances in the negative ion source NIO1
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Barbisan, M., Agnello, R., Cavenago, M., Delogu, R. S., Pimazzoni, A., Balconi, L., Barbato, P., Baseggio, L., Castagni, A., Duteil, B. Pouradier, Franchin, L., Laterza, B., Molon, F., Maniero, M., Migliorato, L., Milazzo, R., Passalacqua, G., Poggi, C., Ravarotto, D., Rizzieri, R., Romanato, L., Rossetto, F., Trevisan, L, Ugoletti, M., Zaniol, B., and Zucchetti, S.
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Physics - Plasma Physics ,Physics - Accelerator Physics - Abstract
Consorzio RFX and INFN-LNL have designed, built and operated the compact radiofrequency negative ion source NIO1 (Negative Ion Optimization phase 1) with the aim of studying the production and acceleration of H- ions. In particular, NIO1 was designed to keep plasma generation and beam extraction continuously active for several hours. Since 2020 the production of negative ions at the plasma grid (the first grid of the acceleration system) has been enhanced by a Cs layer, deposited though active Cs evaporation in the source volume. For the negative ion sources applied to fusion neutral beam injectors, it is essential to keep the beam current and the fraction of co-extracted electrons stable for at least 1 h, against the consequences of Cs sputtering and redistribution operated by the plasma. The paper presents the latest results of the NIO1 source, in terms of caesiation process and beam performances during continuous (6{\div}7 h) plasma pulses. Due to the small dimensions of the NIO1 source (20 x (diam.)10 cm), the Cs density in the volume is high (10^15 \div 10^16 m^-3) and dominated by plasma-wall interaction. The maximum beam current density and minimum fraction of co-extracted electrons were respectively about 30 A/m^2 and 2. Similarly to what done in other negative ion sources, the plasma grid temperature in NIO1 was raised for the first time, up to 80 {\deg}C, although this led to a minimal improvement of the beam current and to an increase of the co-extracted electron current., Comment: 11 pages, 7 figures. Contributed paper for the 8th International symposium on Negative Ions, Beams and Sources - NIBS'22. Revision 1 of the preprint under evaluation at Journal of Instrumentation (JINST)
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- 2022
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15. LSD1 inhibition circumvents glucocorticoid-induced muscle wasting of male mice
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Qingshuang Cai, Rajesh Sahu, Vanessa Ueberschlag-Pitiot, Sirine Souali-Crespo, Céline Charvet, Ilyes Silem, Félicie Cottard, Tao Ye, Fatima Taleb, Eric Metzger, Roland Schuele, Isabelle M. L. Billas, Gilles Laverny, Daniel Metzger, and Delphine Duteil
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Science - Abstract
Abstract Synthetic glucocorticoids (GC), such as dexamethasone, are extensively used to treat chronic inflammation and autoimmune disorders. However, long-term treatments are limited by various side effects, including muscle atrophy. GC activities are mediated by the glucocorticoid receptor (GR), that regulates target gene expression in various tissues in association with cell-specific co-regulators. Here we show that GR and the lysine-specific demethylase 1 (LSD1) interact in myofibers of male mice, and that LSD1 connects GR-bound enhancers with NRF1-associated promoters to stimulate target gene expression. In addition, we unravel that LSD1 demethylase activity is required for triggering starvation- and dexamethasone-induced skeletal muscle proteolysis in collaboration with GR. Importantly, inhibition of LSD1 circumvents muscle wasting induced by pharmacological levels of dexamethasone, without affecting their anti-inflammatory activities. Thus, our findings provide mechanistic insights into the muscle-specific GC activities, and highlight the therapeutic potential of targeting GR co-regulators to limit corticotherapy-induced side effects.
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- 2024
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16. Le « populisme vert » : enjeux désignationnels et effets discursifs
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Carine Duteil and Sophie Anquetil
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populisme vert ,urgence climatique ,expert ,scientificité ,doxa ,Language and Literature - Abstract
Dans cet article, nous nous intéressons à la communication portant sur l’écologie et l’urgence climatique, à travers notamment la notion de « populisme vert ». L’objectif de cette contribution est de ré-interroger la relation a priori d’exclusion entre populisme et scientificité en mettant au jour la nature des voix qui investissent le discours dit populiste. L’étude des textes du candidat Mélenchon (à la présidentielle de 2022) nous permet de questionner cette relation et les formes d’une rhétorique de la scientificité. L’analyse des lexèmes et collocations utilisés nous permet de mettre en évidence l’établissement d’une nouvelle doxa « objectiviste ».
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- 2024
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17. Monostability and bistability of biological switches
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Duteil, Nastassia Pouradier, Guilberteau, Jules, Pouchol, Camille, and Duteil, Nastassia
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Mathematics - Dynamical Systems ,Quantitative Biology - Subcellular Processes - Abstract
Cell-fate transition can be modeled by ordinary differential equations (ODEs) which describe the behavior of several molecules in interaction, and for which each stable equilibrium corresponds to a possible phenotype (or 'biological trait'). In this paper, we focus on simple ODE systems modeling two molecules which each negatively (or positively) regulate the other. It is well-known that such models may lead to monostability or multistability, depending on the selected parameters. However, extensive numerical simulations have led systems biologists to conjecture that in the vast majority of cases, there cannot be more than two stable points. Our main result is a proof of this conjecture. More specifically, we provide a criterion ensuring at most bistability, which is indeed satisfied by most commonly used functions. This includes Hill functions, but also a wide family of convex and sigmoid functions. We also determine which parameters lead to monostability, and which lead to bistability, by developing a more general framework encompassing all our results.
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- 2021
18. Consensus Formation in First-Order Graphon Models with Time-Varying Topologies
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Bonnet, Benoît, Duteil, Nastassia Pouradier, and Sigalotti, Mario
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Mathematics - Optimization and Control ,Mathematics - Functional Analysis ,05C63, 05C90, 37L15, 93A16 - Abstract
In this article, we investigate the asymptotic formation of consensus for several classes of time-dependent cooperative graphon dynamics. After motivating the use of this type of macroscopic models to describe multi-agent systems, we adapt the classical notion of scrambling coefficient to this setting, leverage it to establish sufficient conditions ensuring the exponential convergence to consensus with respect to the $L^{\infty}$-norm topology. We then shift our attention to consensus formation expressed in terms of the $L^2$-norm, and prove three different consensus result for symmetric, balanced and strongly connected topologies, which involve a suitable generalisation of the notion of algebraic connectivity to this infinite-dimensional framework. We then show that, just as in the finite-dimensional setting, the notion of algebraic connectivity that we propose encodes information about the connectivity properties of the underlying interaction topology. We finally use the corresponding results to shed some light on the relation between $L^2$- and $L^{\infty}$-consensus formation, and illustrate our contributions by a series of numerical simulations., Comment: 48 pages, 16 figures
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- 2021
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19. Future changes in atmospheric synoptic variability slow down ocean circulation and decrease primary productivity in the tropical Pacific Ocean
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Duteil, Olaf and Park, Wonsun
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- 2023
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20. Hypercaloric low-carbohydrate high-fat diet protects against the development of nonalcoholic fatty liver disease in obese mice in contrast to isocaloric Western diet
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Anouk Charlot, Anthony Bringolf, Joris Mallard, Anne-Laure Charles, Nathalie Niederhoffer, Delphine Duteil, Allan F. Pagano, Bernard Geny, and Joffrey Zoll
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obesity ,non-alcoholic fatty liver disease ,low-carbohydrate diet ,Western diet ,insulin ,Nutrition. Foods and food supply ,TX341-641 - Abstract
ObjectiveObesity and metabolic complications, such as type 2 diabetes and nonalcoholic fatty liver disease (NAFLD), are one of the greatest public health challenges of the 21st century. The major role of high sugar and carbohydrate consumption rather than caloric intake in obesity and NAFLD pathophysiology remains a subject of debate. A low-carbohydrate but high-fat diet (LCHFD) has shown promising results in obesity management, but its effects in preventing NAFLD need to be detailed. This study aims to compare the effects of a LCHFD with a high-fat high-sugar obesogenic Western diet (WD) on the progression of obesity, type 2 diabetes, and nonalcoholic fatty liver disease.MethodsMale C57BL/6J mice were initially fed a WD for 10 weeks. Subsequently, they were either switched to a LCHFD or maintained on the WD for an additional 6 weeks. Hepatic effects of the diet were explored by histological staining and RT-qPCR.ResultsAfter the initial 10 weeks WD feeding, LCHF diet demonstrated effectiveness in halting weight gain, maintaining a normal glucose tolerance and insulin levels, in comparison to the WD-fed mice, which developed obesity, glucose intolerance, increased insulin levels and induced NAFLD. In the liver, LCHFD mitigated the accumulation of hepatic triglycerides and the increase in Fasn relative gene expression compared to the WD mice. Beneficial effects of the LCHFD occurred despite a similar calorie intake compared to the WD mice.ConclusionOur results emphasize the negative impact of a high sugar/carbohydrate and lipid association for obesity progression and NAFLD development. LCHFD has shown beneficial effects for NAFLD management, notably improving weight management, and maintaining a normal glucose tolerance and liver health.
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- 2024
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21. Future changes in atmospheric synoptic variability slow down ocean circulation and decrease primary productivity in the tropical Pacific Ocean
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Olaf Duteil and Wonsun Park
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Environmental sciences ,GE1-350 ,Meteorology. Climatology ,QC851-999 - Abstract
Abstract This study investigates the impact of future changes in atmospheric synoptic variability (ASV) on ocean properties and biogeochemical cycles in the tropical Pacific Ocean using coupled and forced atmosphere–ocean model experiments. Future climate projections show an annual mean decrease in ASV in subtropical gyres and an increase in the tropical band. Maintaining ASV to current values lead to a deepening of the mixed layer in subtropical regions and a shalllowing at the equator associated with a sea surface temperature decrease. The changes in ASV impact the large-scale ocean circulation and the strength of the subtropical and tropical cells, which constrain the equatorial water upwelling and the tropical net primary productivity. Ultimately, this study highlights the significance of ASV in understanding the impacts of climate change on ocean dynamics and biogeochemical processes, as half of the primary productivity decline due to climate change is caused by changes of ASV in the tropical Pacific Ocean.
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- 2023
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22. Androgen receptor coordinates muscle metabolic and contractile functions
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Kamar Ghaibour, Mélanie Schuh, Sirine Souali‐Crespo, Céline Chambon, Anouk Charlot, Joe Rizk, Daniela Rovito, Anna‐Isavella Rerra, Qingshuang Cai, Nadia Messaddeq, Joffrey Zoll, Delphine Duteil, and Daniel Metzger
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androgen receptor ,genomics ,metabolism ,skeletal muscle ,type 2 diabetes ,Diseases of the musculoskeletal system ,RC925-935 ,Human anatomy ,QM1-695 - Abstract
Abstract Background Androgens are anabolic steroid hormones that exert their function by binding to the androgen receptor (AR). We have previously established that AR deficiency in limb muscles impairs sarcomere myofibrillar organization and decreases muscle strength in male mice. However, despite numerous studies performed in men and rodents, the signalling pathways controlled by androgens via their receptor in skeletal muscles remain poorly understood. Methods Male ARskm−/y (n = 7–12) and female ARskm−/− mice (n = 9), in which AR is selectively ablated in myofibres of musculoskeletal tissue, and male AR(i)skm−/y, in which AR is selectively ablated in post‐mitotic skeletal muscle myofibres (n = 6), were generated. Longitudinal monitoring of body weight, blood glucose, insulin, lipids and lipoproteins was performed, alongside metabolomic analyses. Glucose metabolism was evaluated in C2C12 cells treated with 5α‐dihydrotestosterone (DHT) and the anti‐androgen flutamide (n = 6). Histological analyses on macroscopic and ultrastructural levels of longitudinal and transversal muscle sections were conducted. The transcriptome of gastrocnemius muscles from control and ARskm−/y mice was analysed at the age of 9 weeks (P
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- 2023
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23. Mean-field limit of collective dynamics with time-varying weights
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Duteil, Nastassia Pouradier
- Subjects
Mathematics - Analysis of PDEs - Abstract
In this paper, we derive the mean-field limit of a collective dynamics model with time-varying weights, for weight dynamics that preserve the total mass of the system as well as indistinguishability of the agents. The limit equation is a transport equation with source, where the (non-local) transport term corresponds to the position dynamics, and the (non-local) source term comes from the weight redistribution among the agents. We show existence and uniqueness of the solution for both microscopic and macroscopic models and introduce a new empirical measure taking into account the weights. We obtain the convergence of the microscopic model to the macroscopic one by showing continuity of the macroscopic solution with respect to the initial data, in the Wasserstein and Bounded Lipschitz topologies.
- Published
- 2021
24. First full cool down of the SPIRAL 2 superconducting LINAC
- Author
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Ghribi, Adnan, Aburas, Muhammad, Baumont, Yoann, Bernaudin, Pierre-Emmanuel, Bonneau, Stéphane, Duteil, Guillaume, Ferdinand, Robin, Lechartier, Michel, Leyge, Jean-François, Lescalié, Guillaume, Thivel, Yann, Trudel, Arnaud, Valentin, Laurent, and Vassal, Adrien
- Subjects
Physics - Accelerator Physics ,Physics - Fluid Dynamics - Abstract
SPIRAL 2 is a high intensity heavy ions beams accelerator project that has been going on for more than 10 years now. Countless efforts in different disciplines made it what it is today. One of the most important steps after the set up of the different equipments has been the very first full cool down of the superconducting cavities in an accelerator operation type configuration. While this has been a major achievement for the SPIRAL 2 teams, it also hi-lighted new challenges and constraints that would have to be addressed in order to have a high availability rate of the beam from the cryogenics side. This paper retraces this particular episode.
- Published
- 2021
- Full Text
- View/download PDF
25. Mean-field and graph limits for collective dynamics models with time-varying weights
- Author
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Ayi, Nathalie and Duteil, Nastassia Pouradier
- Subjects
Mathematics - Analysis of PDEs - Abstract
In this paper, we study a model for opinion dynamics where the influence weights of agents evolve in time via an equation which is coupled with the opinions' evolution. We explore the natural question of the large population limit with two approaches: the now classical mean-field limit and the more recent graph limit. After establishing the existence and uniqueness of solutions to the models that we will consider, we provide a rigorous mathematical justification for taking the graph limit in a general context. Then, establishing the key notion of indistinguishability, which is a necessary framework to consider the mean-field limit, we prove the subordination of the mean-field limit to the graph one in that context. This actually provides an alternative (but weaker) proof for the mean-field limit. We conclude by showing some numerical simulations to illustrate our results.
- Published
- 2020
26. Control of collective dynamics with time-varying weights
- Author
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Duteil, Nastassia and Piccoli, Benedetto
- Subjects
Mathematics - Analysis of PDEs ,Mathematics - Dynamical Systems ,Mathematics - Optimization and Control - Abstract
This paper focuses on a model for opinion dynamics, where the influence weights of agents evolve in time. We formulate a control problem of consensus type, in which the objective is to drive all agents to a final target point under suitable control constraints. Controllability is discussed for the corresponding problem with and without constraints on the total mass of the system, and control strategies are designed with the steepest descent approach. The mean-field limit is described both for the opinion dynamics and the control problem. Numerical simulations illustrate the control strategies for the finite-dimensional system.
- Published
- 2020
27. Editorial: Constraining uncertainties in hindcasts and future projections of marine deoxygenation
- Author
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Masahito Shigemitsu, Olaf Duteil, Takamitsu Ito, Jerry Tjiputra, and Yassir Eddebbar
- Subjects
deoxygenation ,oxygen minimum zones ,model uncertainty ,ocean biogeochemical model ,climate projection ,climate change ,Science ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Published
- 2024
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- View/download PDF
28. Kinetic approach to the collective dynamics of the rock-paper-scissors binary game
- Author
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Duteil, Nastassia and Salvarani, Francesco
- Subjects
Mathematics - Analysis of PDEs - Abstract
This article studies the kinetic dynamics of the rock-paper-scissors binary game. We first prove existence and uniqueness of the solution of the kinetic equation and subsequently we prove the rigorous derivation of the quasi-invariant limit for two meaningful choices of the domain of definition of the independent variables. We notice that the domain of definition of the problem plays a crucial role and heavily influences the behavior of the solution. The rigorous proof of the relaxation limit does not need the use of entropy estimates for ensuring compactness.
- Published
- 2020
29. Changes in Macronutrients during Dieting Lead to Weight Cycling and Metabolic Complications in Mouse Model
- Author
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Anouk Charlot, Anthony Bringolf, Léa Debrut, Joris Mallard, Anne-Laure Charles, Emilie Crouchet, Delphine Duteil, Bernard Geny, and Joffrey Zoll
- Subjects
low-carbohydrate high-fat diet ,obesity ,non-alcoholic fatty liver disease ,weight cycling ,nutrition ,carbohydrates ,Nutrition. Foods and food supply ,TX341-641 - Abstract
Weight cycling is a major challenge in obesity management. Caloric restriction is known to promote this phenomenon, but the impact of macronutrient changes during dieting remains unclear. This study aimed to determine the role of macronutrient changes in weight maintenance without caloric restriction by alternating between two hypercaloric diets: a high-carbohydrate, high-fat Western diet (WD) and a low-carbohydrate, high-fat diet (LCHDF). Obesity was induced in 8-week-old C57BL/6 male mice by 10 weeks of WD feeding. Then, the mice were subjected to 12 weeks of LCHFD interspersed with WD (I-WD), 3 periods of 2-week LCHFD followed by 2 periods of 3-week WD, or 12 weeks of continuous WD (C-WD). C-WD and I-WD mice were compared to standard diet (SD) mice. In the I-WD group, each LCHFD period decreased weight gain, but mice regained weight after WD resumption. I-WD mice exhibited obesity, dyslipidemia, and glucose intolerance, similarly to the C-WD mice. I-WD mice also developed nonalcoholic steatohepatitis, associated with an increase in type-III collagen gene expression and a decrease in FGF21 protein levels, in comparison with SD. I-WD mice developed weight cycling despite maintaining a high caloric consumption, suggesting that changes in macronutrients during dieting are also a trigger of weight regain.
- Published
- 2024
- Full Text
- View/download PDF
30. CIGALE: an innovative gas neutralizer based high efficiency neutral beam injector concept for future fusion reactors
- Author
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A. Simonin, H. Bourvard, and B. Pouradier Duteil
- Subjects
reactors ,neutral beam injector ,high efficiency ,gas neutralizer ,recovery energy ,Nuclear and particle physics. Atomic energy. Radioactivity ,QC770-798 - Abstract
This paper outlines the main features of a new high efficiency ( η > 62%) high power (∼18 MW D ^0 ) neutral beam (NB) concept based on pragmatic solutions suitable with the reactor requirements. The injector is modular (several beamlines in parallel) with independent ion sources referenced to the ground potential and gas neutralizers held at +1 MV. This topology leads to numerous simplifications; it overcomes the main issues of conventional NB systems, such as the complex 1 MV electrical setup, the difficult ion source remote maintenance, the high caesium consumption. The other key parameter is the gas neutralization concept which minimizes the amount of gas by operating at a low gas target and low neutralizer duct conductance. The implementation of an energy recovery system for the residual 1 MeV D ^− is essential to attain a high wall-plug efficiency. These specific features require thin laminar D ^− beams provided by a pre-acceleration up to 100 keV in slotted grid apertures to form thin blade-like beamlets, followed by the post-acceleration to 1 MeV by merging the beamlets in a single beam in five gaps (+200 kV per gap). All these specific aspects minimize the beams losses and thermal loads along the beamline and enhance the injector reliability and availability.
- Published
- 2024
- Full Text
- View/download PDF
31. Prevention of Polymorphic Light Eruption Afforded by a Very High Broad-Spectrum Protection Sunscreen Containing Ectoin
- Author
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Duteil, Luc, Queille-Roussel, Catherine, Aladren, Sonia, Bustos, Xavier, Trullas, Carles, Granger, Corinne, Krutmann, Jean, and Passeron, Thierry
- Published
- 2022
- Full Text
- View/download PDF
32. Sparse control of Hegselmann-Krause models: Black hole and declustering
- Author
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Piccoli, Benedetto, Duteil, Nastassia Pouradier, and Trélat, Emmanuel
- Subjects
Mathematics - Optimization and Control - Abstract
This paper elaborates control strategies to prevent clustering effects in opinion formation models. This is the exact opposite of numerous situations encountered in the literature where, on the contrary, one seeks controls promoting consensus. In order to promote declustering, instead of using the classical variance that does not capture well the phenomenon of dispersion, we introduce an entropy-type functional that is adapted to measuring pairwise distances between agents. We then focus on a Hegselmann-Krause-type system and design declustering sparse controls both in finite-dimensional and kinetic models. We provide general conditions characterizing whether clustering can be avoided as function of the initial data. Such results include the description of black holes (where complete collapse to consensus is not avoidable), safety zones (where the control can keep the system far from clustering), basins of attraction (attractive zones around the clustering set) and collapse prevention (when convergence to the clustering set can be avoided).
- Published
- 2018
33. Efficacy and safety of 0.05% ingenol mebutate in the treatment of basal cell carcinoma: A prospective study
- Author
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Marine Velin, Nathalie Cardot‐Leccia, Anne‐Claire Cathelineau, Luc Duteil, Catherine Queille‐Roussel, Thierry Passeron, and Philippe Bahadoran
- Subjects
Dermatology ,RL1-803 - Published
- 2023
- Full Text
- View/download PDF
34. Les communautés chrétiennes de la Chine des XVIIe et XVIIIe siècles ont-elles été clandestines ?
- Author
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Jean-Pierre Duteil
- Subjects
Visual arts ,N1-9211 - Abstract
La question de la clandestinité se pose à propos des chrétiens de la Chine impériale, convertis en petit nombre à partir des premières années du XVIIe siècle. Ont-ils véritablement vécu cachés pendant près de trois siècles, comme ceux du Japon ? Afin d’apporter quelques éléments de réponse, cet article examine d’abord les sources dont nous disposons. Tant manuscrites qu’imprimées, elles sont relativement nombreuses et riches, sous forme de correspondances ou de récits missionnaires. Mais elles sont partiales, et à ce titre doivent faire l’objet de nombreuses précautions. Elles nous renseignent sur le réseau des chrétientés, examiné dans la deuxième partie de cet article, ainsi que sur l’évolution du pouvoir impérial chinois, qui fait l’objet de la troisième partie. En effet, certaines modifications juridiques permettent de faire évoluer le statut des religieux, mais cela concerne surtout ceux qui sont en rapport direct avec le palais impérial. Le sort des missionnaires et des communautés qui se trouvent dans les diverses provinces n’en est amélioré que par contrecoup. La vie des communautés chrétiennes, examinée dans une quatrième partie, montre que ces dernières vivent de manière discrète plus que véritablement secrète. Les chrétiens de Chine sont restés dans la semi-clandestinité jusqu’à la fin de l’empire, au début du XXe siècle. Apparemment, leur seule alternative était la fusion dans la culture locale ou le repli, ce qui semblait vouer ces clandestins à la disparition, qui en fin de compte n’a pas eu lieu.
- Published
- 2022
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- View/download PDF
35. The riddle of eastern tropical Pacific Ocean oxygen levels: the role of the supply by intermediate-depth waters
- Author
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O. Duteil, I. Frenger, and J. Getzlaff
- Subjects
Geography. Anthropology. Recreation ,Environmental sciences ,GE1-350 - Abstract
Observed oxygen minimum zones (OMZs) in the tropical Pacific Ocean are located above intermediate-depth waters (IDWs), defined here as the 500–1500 m water layer. Typical climate models do not represent IDW properties well and are characterized by OMZs that are too deep-reaching. We analyze the role of the IDW in the misrepresentation of oxygen levels in a heterogeneous subset of ocean models characterized by a horizontal resolution ranging from 0.1 to 2.8∘. First, we show that forcing the extratropical boundaries (30∘ S and N) to observed oxygen values results in a significant increase in oxygen levels in the intermediate eastern tropical region. Second, we highlight the fact that the Equatorial Intermediate Current System (EICS) is a key feature connecting the western and eastern part of the basin. Typical climate models lack in representing crucial aspects of this supply at intermediate depth, as the EICS is basically absent in models characterized by a resolution lower than 0.25∘. These two aspects add up to a “cascade of biases” that hampers the correct representation of oxygen levels at intermediate depth in the eastern tropical Pacific Ocean and potentially future OMZ projections.
- Published
- 2021
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- View/download PDF
36. COVID-19 wastewater based epidemiology: long-term monitoring of 10 WWTP in France reveals the importance of the sampling context
- Author
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A. Lazuka, C. Arnal, E. Soyeux, M. Sampson, A.-S. Lepeuple, Y. Deleuze, S. Pouradier Duteil, and S. Lacroix
- Subjects
covid-19 ,public health ,rt-qpcr ,sampling context ,sars-cov-2 ,wastewater-based epidemiology ,Environmental technology. Sanitary engineering ,TD1-1066 - Abstract
SARS-CoV-2 wastewater-based epidemiology (WBE) has been advanced as a relevant indicator of distribution of COVID-19 in communities, supporting classical testing and tracing epidemiological approaches. An extensive sampling campaign, including ten municipal wastewater treatment plants, has been conducted in different cities of France over a 20-week period, encompassing the second peak of COVID-19 outbreak in France. A well-recognised ultrafiltration – RNA extraction – RT-qPCR protocol was used and qualified, showing 5.5 +/− 0.5% recovery yield on heat-inactivated SARS-CoV-2. Importantly the whole, solid and liquid, fraction of wastewater was used for virus concentration in this study. Campaign results showed medium- to strong- correlation between SARS-CoV-2 WBE data and COVID-19 prevalence. To go further, statistical relationships between WWTP inlet flow rate and rainfall were studied and taken into account for each WWTP in order to calculate contextualized SARS-CoV-2 loads. This metric presented improved correlation strengths with COVID-19 prevalence for WWTP particularly submitted and sensitive to rain. Such findings highlighted that SARS-CoV-2 WBE data ultimately require to be contextualized for relevant interpretation. HIGHLIGHTS First study monitoring inlet of 10 WWTPs located in France for SARS-CoV-2 RNA quantification over a 20-week period encompassing the second peak of COVID-19 outbreak.; Viral recovery yield was 5.5% +/− 0.5% using heat-inactivated SARS-CoV-2.; Medium to high Spearman's correlation strength was observed between SARS-CoV-2 WBE and COVID-19 prevalence data.; Considering sampling context (i.e. rain events) improved data consistency and correlation strength.;
- Published
- 2021
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- View/download PDF
37. Interaction Network, State Space and Control in Social Dynamics
- Author
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Aydogdu, Aylin, Caponigro, Marco, McQuade, Sean, Piccoli, Benedetto, Duteil, Nastassia Pouradier, Rossi, Francesco, and Trélat, Emmanuel
- Subjects
Mathematics - Dynamical Systems ,Physics - Physics and Society - Abstract
In the present chapter we study the emergence of global patterns in large groups in first and second-order multi-agent systems, focusing on two ingredients that influence the dynamics: the interaction network and the state space. The state space determines the types of equilibrium that can be reached by the system. Meanwhile, convergence to specific equilibria depends on the connectivity of the interaction network and on the interaction potential. When the system does not satisfy the necessary conditions for convergence to the desired equilibrium, control can be exerted, both on finite-dimensional systems and on their mean-field limit., Comment: Chapter of the Birkhauser-Springer book (to appear) by N. Bellomo, P. Degond, and E. Tadmor Eds., "Active Particles Volume 1, Theory, Methods, and Applications"
- Published
- 2016
38. Control of reaction-diffusion equations on time-evolving manifolds
- Author
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Rossi, Francesco, Duteil, Nastassia Pouradier, Yakoby, Nir, and Piccoli, Benedetto
- Subjects
Mathematics - Optimization and Control ,Mathematics - Analysis of PDEs - Abstract
Among the main actors of organism development there are morphogens, which are signaling molecules diffusing in the developing organism and acting on cells to produce local responses. Growth is thus determined by the distribution of such signal. Meanwhile, the diffusion of the signal is itself affected by the changes in shape and size of the organism. In other words, there is a complete coupling between the diffusion of the signal and the change of the shapes. In this paper, we introduce a mathematical model to investigate such coupling. The shape is given by a manifold, that varies in time as the result of a deformation given by a transport equation. The signal is represented by a density, diffusing on the manifold via a diffusion equation. We show the non-commutativity of the transport and diffusion evolution by introducing a new concept of Lie bracket between the diffusion and the transport operator. We also provide numerical simulations showing this phenomenon.
- Published
- 2016
39. Preservation of exopolymeric substances in estuarine sediments
- Author
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Thibault Duteil, Raphaël Bourillot, Olivier Braissant, Brian Grégoire, Maud Leloup, Eric Portier, Benjamin Brigaud, Hugues Féniès, Isabelle Svahn, Adrien Henry, Yusuke Yokoyama, and Pieter T. Visscher
- Subjects
estuarine sediments ,diatom biofilms ,exopolymeric substances ,FTIR – spectroscopy ,cryo-SEM ,sedimentary core ,Microbiology ,QR1-502 - Abstract
The surface of intertidal estuarine sediments is covered with diatom biofilms excreting exopolymeric substances (EPSs) through photosynthesis. These EPSs are highly reactive and increase sediment cohesiveness notably through organo-mineral interactions. In most sedimentary environments, EPSs are partly to fully degraded by heterotrophic bacteria in the uppermost millimeters of the sediment and so they are thought to be virtually absent deeper in the sedimentary column. Here, we present the first evidence of the preservation of EPSs and EPS-mineral aggregates in a 6-m-long sedimentary core obtained from an estuarine point bar in the Gironde Estuary. EPSs were extracted from 18 depth intervals along the core, and their physicochemical properties were characterized by (i) wet chemical assays to measure the concentrations of polysaccharides and proteins, and EPS deprotonation of functional groups, (ii) acid–base titrations, and (iii) Fourier transform infrared spectroscopy. EPS-sediment complexes were also imaged using cryo-scanning electron microscopy. EPS results were analyzed in the context of sediment properties including facies, grain size, and total organic carbon, and of metabolic and enzymatic activities. Our results showed a predictable decrease in EPS concentrations (proteins and polysaccharides) and reactivity from the surface biofilm to a depth of 0.5 m, possibly linked to heterotrophic degradation. Concentrations remained relatively low down to ca. 4.3 m deep. Surprisingly, at that depth EPSs abundance was comparable to the surface and showed a downward decrease to 6.08 m. cryo-scanning electron microscopy (Cryo-SEM) showed that the EPS complexes with sediment were abundant at all studied depth and potentially protected EPSs from degradation. EPS composition did not change substantially from the surface to the bottom of the core. EPS concentrations and acidity were anti-correlated with metabolic activity, but showed no statistical correlation with grain size, TOC, depth or enzymatic activity. Maximum EPS concentrations were found at the top of tide-dominated sedimentary sequences, and very low concentrations were found in river flood-dominated sedimentary sequences. Based on this observation, we propose a scenario where biofilm development and EPS production are maximal when (i) the point bar and the intertidal areas were the most extensive, i.e., tide-dominated sequences and (ii) the tide-dominated deposit were succeeded by rapid burial beneath sediments, potentially decreasing the probability of encounter between bacterial cells and EPSs.
- Published
- 2022
- Full Text
- View/download PDF
40. Design and Development of a Diagnostic System for a Non-Intercepting Direct Measure of the SPIDER Ion Source Beamlet Current
- Author
-
Tommaso Patton, Alastair Shepherd, Basile Pouradier Duteil, Andrea Rigoni Garola, Matteo Brombin, Valeria Candeloro, Gabriele Manduchi, Mauro Pavei, Roberto Pasqualotto, Antonio Pimazzoni, Marco Siragusa, Gianluigi Serianni, Emanuele Sartori, Cesare Taliercio, Paolo Barbato, Vannino Cervaro, Raffaele Ghiraldelli, Bruno Laterza, and Federico Rossetto
- Subjects
neutral beam injector ,negative ions accelerator ,beam fluctuations ,SPIDER ,ITER ,Chemical technology ,TP1-1185 - Abstract
Stable and uniform beams with low divergence are required in particle accelerators; therefore, beyond the accelerated current, measuring the beam current spatial uniformity and stability over time is necessary to assess the beam performance, since these parameters affect the perveance and thus the beam optics. For high-power beams operating with long pulses, it is convenient to directly measure these current parameters with a non-intercepting system due to the heat management requirement. Such a system needs to be capable of operating in a vacuum in the presence of strong electromagnetic fields and overvoltages, due to electrical breakdowns in the accelerator. Finally, the measure of the beam current needs to be efficiently integrated into a pulse file with the other relevant plant parameters to allow the data analyses required for beam optimization. This paper describes the development, design and commissioning of such a non-intercepting system, the so-called beamlet current monitor (BCM), aimed to directly measure the electric current of a particle beam. In particular, the layout of the system was adapted to the SPIDER experiment, the ion source (IS) prototype of the heating neutral beam injectors (HNB) for the ITER fusion reactor. The diagnostic is suitable to provide the electric current of five beamlets from DC up to 10 MHz.
- Published
- 2023
- Full Text
- View/download PDF
41. Do Loop Current eddies stimulate productivity in the Gulf of Mexico?
- Author
-
P. Damien, J. Sheinbaum, O. Pasqueron de Fommervault, J. Jouanno, L. Linacre, and O. Duteil
- Subjects
Ecology ,QH540-549.5 ,Life ,QH501-531 ,Geology ,QE1-996.5 - Abstract
Surface chlorophyll concentrations inferred from satellite images suggest a strong influence of the mesoscale activity on biogeochemical variability within the oligotrophic regions of the Gulf of Mexico (GoM). More specifically, long-living anticyclonic Loop Current eddies (LCEs) are shed episodically from the Loop Current and propagate westward. This study addresses the biogeochemical response of the LCEs to seasonal forcing and show their role in driving phytoplankton biomass distribution in the GoM. Using an eddy resolving (1/12∘) interannual regional simulation, it is shown that the LCEs foster a large biomass increase in winter in the upper ocean. It is based on the coupled physical–biogeochemical model NEMO-PISCES (Nucleus for European Modeling of the Ocean and Pelagic Interaction Scheme for Carbon and Ecosystem Studies) that yields a realistic representation of the surface chlorophyll distribution. The primary production in the LCEs is larger than the average rate in the surrounding open waters of the GoM. This behavior cannot be directly identified from surface chlorophyll distribution alone since LCEs are associated with a negative surface chlorophyll anomaly all year long. This anomalous biomass increase in the LCEs is explained by the mixed-layer response to winter convective mixing that reaches deeper and nutrient-richer waters.
- Published
- 2021
- Full Text
- View/download PDF
42. Developmental Partial Differential Equations
- Author
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Duteil, Nastassia Pouradier, Rossi, Francesco, Boscain, Ugo, and Piccoli, Benedetto
- Subjects
Mathematics - Optimization and Control - Abstract
In this paper, we introduce the concept of Developmental Partial Differential Equation (DPDE), which consists of a Partial Differential Equation (PDE) on a time-varying manifold with complete coupling between the PDE and the manifold's evolution. In other words, the manifold's evolution depends on the solution to the PDE, and vice versa the differential operator of the PDE depends on the manifold's geometry. DPDE is used to study a diffusion equation with source on a growing surface whose growth depends on the intensity of the diffused quantity. The surface may, for instance, represent the membrane of an egg chamber and the diffused quantity a protein activating a signaling pathway leading to growth. Our main objective is to show controllability of the surface shape using a fixed source with variable intensity for the diffusion. More specifically, we look for a control driving a symmetric manifold shape to any other symmetric shape in a given time interval. For the diffusion we take directly the Laplace-Beltrami operator of the surface, while the surface growth is assumed to be equal to the value of the diffused quantity. We introduce a theoretical framework, provide approximate controllability and show numerical results. Future applications include a specific model for the oogenesis of Drosophila melanogaster., Comment: 7 pages. Paper submitted for CDC 2015
- Published
- 2015
43. Optimal Control of a Collective Migration Model
- Author
-
Piccoli, Benedetto, Duteil, Nastassia Pouradier, and Scharf, Benjamin
- Subjects
Mathematics - Optimization and Control - Abstract
Collective migration of animals in a cohesive group is rendered possible by a strategic distribution of tasks among members: some track the travel route, which is time and energy-consuming, while the others follow the group by interacting among themselves. In this paper, we study a social dynamics system modeling collective migration. We consider a group of agents able to align their velocities to a global target velocity, or to follow the group via interaction with the other agents. The balance between these two attractive forces is our control for each agent, as we aim to drive the group to consensus at the target velocity. We show that the optimal control strategies in the case of final and integral costs consist of controlling the agents whose velocities are the furthest from the target one: these agents sense only the target velocity and become leaders, while the uncontrolled ones sense only the group, and become followers. Moreover, in the case of final cost, we prove an "Inactivation" principle: there exist initial conditions such that the optimal control strategy consists of letting the system evolve freely for an initial period of time, before acting with full control on the agent furthest from the target velocity., Comment: 25 pages, 6 figures
- Published
- 2015
44. What do patients consulting in a free sexual health center know about HIV transmission and post-exposure prophylaxis?
- Author
-
Christelle Duteil, Elise de La Rochebrochard, Prescillia Piron, Christophe Segouin, and Pénélope Troude
- Subjects
HIV ,Knowledge ,False beliefs ,Free HIV and sexually transmitted infection screening center ,Post-exposure prophylaxis ,Public aspects of medicine ,RA1-1270 - Abstract
Abstract Background Screening, condom use and post-exposure prophylaxis (PEP) are among existing HIV prevention strategies. However, efficient use of these strategies requires that patients have an adequate knowledge of HIV transmission routes and awareness of risk behaviors. This study aimed to assess knowledge about HIV transmission among patients who attended a free HIV and sexually transmitted infection (STI) screening center in Paris, France, and to explore the patient profiles associated with HIV-related knowledge. Methods This observational cross-sectional study included 2002 patients who attended for STI testing from August 2017 through August 2018 and completed a self-administered electronic questionnaire. Based on incorrect answers regarding HIV transmission, two outcomes were assessed: lack of knowledge and false beliefs. Factors associated with these two outcomes were explored using univariate and multivariate logistic regressions. Results Only 3.6% of patients did not know about HIV transmission through unprotected sexual intercourse and/or by sharing needles. More than one third of patients (36.4%) had at least one false belief, believing that HIV could be transmitted by sharing a drink (9.7%), kissing (17.6%) or using public toilets (27.5%). A low educational level and no previous HIV testing were associated in multivariate analyses with both lack of knowledge and false beliefs. Age and sexual orientation were also associated with false beliefs. Furthermore, 55.6% of patients did not know that post-exposure prophylaxis consists of taking emergency treatment as soon as possible after risky intercourse. Conclusions Although the main HIV transmission routes are well known, false beliefs persist and knowledge regarding PEP needs to be improved. Prevention campaigns must focus on these themes which appear as a complementary strategy to pre-exposure prophylaxis to reduce HIV infection.
- Published
- 2021
- Full Text
- View/download PDF
45. The antiaging effects of a product containing collagen and ascorbic acid: In vitro, ex vivo, and pre-post intervention clinical trial.
- Author
-
Tae Kyeong Ryu, Hanna Lee, Dong Keon Yon, Da Yeong Nam, Soo Yun Lee, Byung Ho Shin, Go Woon Choi, Da Som Jeon, Bo Bae Oh, Ji Hyun Kim, Young Yoon, Hyun Jeong Kim, Luc Duteil, Christelle Bruno-Bonnet, Chan Yeong Heo, and So Min Kang
- Subjects
Medicine ,Science - Abstract
Various substances, including collagen (Naticol®) and ascorbic acid, that inhibit and prevent skin aging have been studied. Collagen prevents skin aging, has anti-inflammatory effects, and assists in normal wound healing. Ascorbic acid is a representative antioxidant that plays a role in collagen synthesis. To achieve a synergistic effect of collagen and ascorbic acid on all skin types, we prepared a product named "TEENIALL." In addition, we used a container to separate ascorbic acid and collagen to prevent the oxidation of ascorbic acid. To confirm the effects of TEENIALL, we first confirmed its penetrability in fibroblasts, keratinocytes, melanocyte, and human skin tissues. Thereafter, we confirmed the collagen synthesis ability in normal human fibroblasts. Based on the results of in vitro tests, we conducted a clinical trial (KCT0006916) on female volunteers, aged 40 to 59 years, with skin wrinkles and hyperpigmentation, to evaluate the effects of the product in improving skin wrinkles, skin lifting, and pigmentation areas before using the product, and after 2 and 4 weeks of using the product. The values of nine wrinkle parameters that were evaluated decreased and those for skin sagging, pigmentation, dermal density, and mechanical imprint (pressure) relief were improved. Skin wrinkle and pigmentation were evaluated to ensure that the improvement effect was maintained even after 1 week of discontinuing the product use. The evaluation confirmed that the effects were sustained compared to those after 4 weeks of using the product. Additionally, skin wrinkles, skin lifting, radiance, and moisture content in the skin improved immediately after using the product once. Based on the results of in vitro and ex vivo experiments and the clinical trial, we show that the product containing ascorbic acid and collagen was effective in alleviating skin aging.
- Published
- 2022
- Full Text
- View/download PDF
46. What do patients consulting in a free sexual health center know about HIV transmission and post-exposure prophylaxis?
- Author
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Duteil, Christelle, de La Rochebrochard, Elise, Piron, Prescillia, Segouin, Christophe, and Troude, Pénélope
- Published
- 2021
- Full Text
- View/download PDF
47. Monostability and bistability of biological switches
- Author
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Guilberteau, Jules, Pouchol, Camille, and Pouradier Duteil, Nastassia
- Published
- 2021
- Full Text
- View/download PDF
48. Les valeurs de l’Olympisme dans et par le discours : topique instituante et dynamique du sens
- Author
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Carine DUTEIL, Arnaud RICHARD, and Julien LONGHI
- Subjects
actes de langage ,topique ,valeurs ,sport ,olympisme ,Language and Literature - Abstract
Cet article s’intéresse aux discours traitant du sport (politique, institutionnel, olympique, etc.) ainsi qu’aux discours issus de pratiques sportives (forums, réseaux sociaux et applications dédiées au sport), afin de questionner les valeurs de l’Olympisme et la manière dont elles sont mises en discours et polarisées. Le corpus est composé de textes institutionnels majeurs (chartes et codes essentiellement). Son étude est complétée par l’analyse d’un second corpus comprenant des « posts » diffusés sur les forums et réseaux sociaux sportifs ainsi que des publications relatives à la communauté Strava. Nous décrivons comment les textes qui régissent l’Olympisme formulent une topique instituante, et comment le sens des valeurs évolue à travers l’actualisation discursive, dans des contextes renvoyant à la pratique du sport amateur. Nous interrogeons en particulier le Respect, l’Amitié et l’Excellence (les trois valeurs essentielles revendiquées par le mouvement olympisme) et leurs liens avec d’autres valeurs (la paix entre les peuples, l’égalité, la solidarité, l’intégrité). L'analyse discursive in situ permet de cerner les enjeux de la reconfiguration de ces fondamentaux dans les pratiques numériques des amateurs, autour du fair-play, de la performance, et plus généralement de ce qui est entendu par « valeurs du sport ».
- Published
- 2021
- Full Text
- View/download PDF
49. Investigations on Caesium Dispersion and Molybdenum Coating on SPIDER Components
- Author
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Valentina Candela, Caterina Cavallini, Claudia Gasparrini, Lidia Armelao, Valeria Candeloro, Mauro Dalla Palma, Michele Fadone, Diego Marcuzzi, Mauro Pavei, Adriano Pepato, Basile Pouradier Duteil, Marzio Rancan, Andrea Rizzolo, Emanuele Sartori, Beatrice Segalini, Gianluigi Serianni, Monica Spolaore, Federico Zorzi, and Piergiorgio Sonato
- Subjects
SPIDER ,ITER ,caesium evaporation ,NBI ,caesium deposits ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
SPIDER is the 100 keV full-size Negative Ion Source prototype of the ITER Neutral Beam Injector, operating at Consorzio RFX in Padova, Italy. The largest Negative Ion Source in the world, SPIDER generates an RF driven plasma from which Deuterium or Hydrogen negative ions are produced and extracted. At the end of 2021, a scheduled long-term shutdown started to introduce major modifications and improvements aiming to solve issues and drawbacks identified during the first three years of SPIDER operations. The first action of the shutdown period was the disassembly and characterization of the SPIDER beam source after removal from the vacuum vessel and its placement inside the clean room. Each component was carefully assessed and catalogued, following a documented procedure. Some source components, i.e., the Plasma Grid, Extraction Grid and Bias Plate, revealed the presence of different and non-uniform red, white and green coatings that might be correlated to back-streaming positive ions impinging on grid surfaces, electrical discharges and caesium evaporation. Thus, several analyses have been carried out to understand the nature of such coatings, with the study still ongoing. The evidence of caesium evaporation and deposition on molybdenum-coated SPIDER components, such as the formation of oxides and hydroxides, is demonstrated through surface characterization analyses with the use of the Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS).
- Published
- 2022
- Full Text
- View/download PDF
50. Pacific Decadal Oscillation and recent oxygen decline in the eastern tropical Pacific Ocean
- Author
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O. Duteil, A. Oschlies, and C. W. Böning
- Subjects
Ecology ,QH540-549.5 ,Life ,QH501-531 ,Geology ,QE1-996.5 - Abstract
The impact of the positive and negative phases of the Pacific Decadal Oscillation (PDO) on the extension of the poorly oxygenated regions of the eastern Pacific Ocean was assessed using a coupled ocean circulation–biogeochemical model. We show that during a “typical” PDO-positive phase the volume of the suboxic regions expands by 7 % over 50 years due to a slowdown of the large-scale circulation related to the decrease in the intensity of the trade winds. Changes in oxygen levels are mostly controlled by advective processes between 10∘ N and 10∘ S, whereas diffusive processes are dominant poleward of 10∘: in a “typical” PDO-positive phase the sluggish equatorial current system provides less oxygen to the eastern equatorial part of the basin while the oxygen transport by diffusive processes significantly decreases south of 10∘ S. The suboxic region located north of 10∘ N displays less sensitivity to the phase of the PDO as the local upwelling-related processes play a dominant role compared to the large-scale circulation in setting the oxygen concentration. Our study suggests that the prevailing PDO-positive conditions since 1975 may explain a significant part of the current deoxygenation occurring in the eastern Pacific Ocean.
- Published
- 2018
- Full Text
- View/download PDF
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