1,444 results on '"Vignon P"'
Search Results
2. Estimation of the Clinical, Economic, and Social Burden of Stage IV Non-Small Cell Lung Cancer in Mexico
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Añorve Bailon, Denisse, Picó-Guzmán, Javier, Cifuentes, Sergio, Trejo, Rogelio, Rodríguez Cid, Jeronimo, Juarez-Vignon Whaley, Juan Jose, Heredia Zepeda, Alan Alexis, Gerson, Raquel, Camacho-Limas, Christian Patricio, Martínez-Herrera, José Fabián, Molina, Diana Bonilla, Camarín Sánchez, Efraín, and Shveid Gerson, Daniela
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- 2024
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3. Therapeutic impact of basic critical care echocardiography performed by residents after limited training
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Marine Goudelin, Bruno Evrard, Roxana Donisanu, Céline Gonzalez, Christophe Truffy, Marie Orabona, Antoine Galy, François-Xavier Lapébie, Yvan Jamilloux, Elodie Vandeix, Dominique Belcour, Charles Hodler, Lucie Ramirez, Rémi Gagnoud, Catherine Chapellas, and Philippe Vignon
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Transthoracic echocardiography ,Training ,Intensive care unit ,Point of care technology ,Therapeutic uses ,Ultrasound ,Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Abstract Background The objective was to assess the agreement between therapeutic proposals derived from basic critical care echocardiography performed by novice operators in ultrasonography after a limited training (residents) and by experts considered as reference. Secondary objectives were to assess the agreement between operators’ answers to simple clinical questions and the concordance between basic two-dimensional measurements. Methods This observational, prospective, single-center study was conducted over a 3-year period in a medical-surgical intensive care unit. Adult patients with acute circulatory and/or respiratory failure requiring a transthoracic echocardiography (TTE) examination were studied. In each patient, a TTE was performed by a resident novice in ultrasonography after a short training program and by an expert, independently but within 1 h and in random order. Each operator addressed standardized simple clinical questions and subsequently proposed a therapeutic strategy based on a predefined algorithm. Results Residents performed an average of 33 TTE studies in 244 patients (156 men; age: 63 years [52–74]; SAPS2: 45 [34–59]; 182 (75%) mechanically ventilated). Agreement between the therapeutic proposals of residents and experienced operators was good-to-excellent. The concordance was excellent for suggesting fluid loading, inotrope or vasopressor support (all Kappa values > 0.80). Inter-observer agreement was only moderate when considering the indication of negative fluid balance (Kappa: 0.65; 95% CI 0.50–0.80), since residents proposed diuretics in 23 patients (9.5%) while their counterparts had the same suggestion in 35 patients (14.4%). Overall agreement of responses to simple clinical questions was also good-to-excellent. Intraclass correlation coefficient exceeded 0.75 for measurement of ventricular and inferior vena cava size. Conclusions A limited training program aiming at acquiring the basic level in critical care echocardiography enables ICU residents novice in ultrasonography to propose therapeutic interventions with a good-to-excellent agreement with experienced operators.
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- 2024
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4. Zero set of Zak transform and the HRT Conjecture
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Oussa, Vignon
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Mathematics - Functional Analysis - Abstract
The HRT (Heil-Ramanathan-Topiwala) posits the linear independence of any set of nonzero square-integrable vectors obtained from a single nonzero vector $f$ by applying a finite set of time-frequency shift operators. In this short note, we present findings centered on the zero set of the Zak transform of $f$, and a distinct arrangement involving a finite set of $N$ points on an integer lattice in the time-frequency plane, excluding a specific point.
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- 2023
5. Effective control of two-dimensional Rayleigh--B\'enard convection: invariant multi-agent reinforcement learning is all you need
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Vignon, Colin, Rabault, Jean, Vasanth, Joel, Alcántara-Ávila, Francisco, Mortensen, Mikael, and Vinuesa, Ricardo
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Physics - Fluid Dynamics ,Computer Science - Machine Learning - Abstract
Rayleigh-B\'enard convection (RBC) is a recurrent phenomenon in several industrial and geoscience flows and a well-studied system from a fundamental fluid-mechanics viewpoint. However, controlling RBC, for example by modulating the spatial distribution of the bottom-plate heating in the canonical RBC configuration, remains a challenging topic for classical control-theory methods. In the present work, we apply deep reinforcement learning (DRL) for controlling RBC. We show that effective RBC control can be obtained by leveraging invariant multi-agent reinforcement learning (MARL), which takes advantage of the locality and translational invariance inherent to RBC flows inside wide channels. The MARL framework applied to RBC allows for an increase in the number of control segments without encountering the curse of dimensionality that would result from a naive increase in the DRL action-size dimension. This is made possible by the MARL ability for re-using the knowledge generated in different parts of the RBC domain. We show in a case study that MARL DRL is able to discover an advanced control strategy that destabilizes the spontaneous RBC double-cell pattern, changes the topology of RBC by coalescing adjacent convection cells, and actively controls the resulting coalesced cell to bring it to a new stable configuration. This modified flow configuration results in reduced convective heat transfer, which is beneficial in several industrial processes. Therefore, our work both shows the potential of MARL DRL for controlling large RBC systems, as well as demonstrates the possibility for DRL to discover strategies that move the RBC configuration between different topological configurations, yielding desirable heat-transfer characteristics. These results are useful for both gaining further understanding of the intrinsic properties of RBC, as well as for developing industrial applications., Comment: 34 pages, 11 figures submitted to Physics of Fluids
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- 2023
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6. Therapeutic impact of basic critical care echocardiography performed by residents after limited training
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Goudelin, Marine, Evrard, Bruno, Donisanu, Roxana, Gonzalez, Céline, Truffy, Christophe, Orabona, Marie, Galy, Antoine, Lapébie, François-Xavier, Jamilloux, Yvan, Vandeix, Elodie, Belcour, Dominique, Hodler, Charles, Ramirez, Lucie, Gagnoud, Rémi, Chapellas, Catherine, and Vignon, Philippe
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- 2024
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7. Fluid responsiveness and venous congestion: unraveling the nuances of fluid status
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Joseph, Adrien, Petit, Matthieu, Vignon, Philippe, and Vieillard-Baron, Antoine
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- 2024
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8. Right ventricular injury in patients with COVID-19-related ARDS eligible for ECMO support: a multicenter retrospective study
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Petit, Matthieu, Bouaoud, Misylias, Jullien, Edouard, Joseph, Adrien, Evrard, Bruno, Charron, Cyril, Daulasim, Anousone, Legras, Annick, Gourraud, Maeva, Goudelin, Marine, Vignon, Philippe, and Vieillard-Baron, Antoine
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- 2024
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9. Recent advances in applying deep reinforcement learning for flow control: perspectives and future directions
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Vignon, Colin, Rabault, Jean, and Vinuesa, Ricardo
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Physics - Fluid Dynamics - Abstract
Deep reinforcement learning (DRL) has been applied to a variety of problems during the past decade, and has provided effective control strategies in high-dimensional and non-linear situations that are challenging to traditional methods. Flourishing applications now spread out into the field of fluid dynamics, and specifically of active flow control (AFC). In the community of AFC, the encouraging results obtained in two-dimensional and chaotic conditions have raised interest to study increasingly complex flows. In this review, we first provide a general overview of the reinforcement-learning (RL) and DRL frameworks, as well as their recent advances. We then focus on the application of DRL to AFC, highlighting the current limitations of the DRL algorithms in this field, and suggesting some of the potential upcoming milestones to reach, as well as open questions that are likely to attract the attention of the fluid-mechanics community.
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- 2023
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10. Cancer of Unknown Primary: When Imaging, Pathology, and Molecular Biology Do Not Match
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Juan Jose Juarez-Vignon Whaley, Prateek Pophali, Yevgen Chornenkyy, and Mary Linton Peters
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cancer of unknown primary ,occult primary ,molecular testing ,next-generation sequencing ,multidisciplinary team ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Introduction: Cancers of unknown primary are aggressive and rare malignancies with a complex diagnosis and management. Here we present a case in which imaging, pathology, and molecular biology did not match for a specific tumor site and the importance of a multidisciplinary team for these complicated cases. Case Presentation: A man in his 70s with strong smoking history under workup for suspicion of metastatic lung cancer underwent lung mass biopsy. Immunohistochemical stains corresponded to hepatocellular/cholangiocarcinoma or germ cell tumor; however, dedicated liver and testicular studies including imaging and iscochrome 12p FISH were negative. Additionally, somatic variant profiling was not specific for any malignancy nor targetable variants. Given the pattern of disease, risk factors, and patient history, the patient received treatment for lung adenocarcinoma (carboplatin, pemetrexed, and pembrolizumab). The patient had a drastic improvement in dyspnea, weight gain, and was able to return to work. Conclusion: This report describes a case in which immunohistochemistry and molecular profiling did not identify the tissue of origin and highlights the importance of a multidisciplinary team to reach a diagnosis and guide treatment without delaying patient care in patients with these diagnoses.
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- 2024
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11. CoRe: An Automated Pipeline for The Prediction of Liver Resection Complexity from Preoperative CT Scans
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Ali, Omar, Bone, Alexandre, Accardo, Caterina, Belkouchi, Omar, Rohe, Marc-Michel, Vibert, Eric, and Vignon-Clementel, Irene
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Electrical Engineering and Systems Science - Image and Video Processing ,Computer Science - Computer Vision and Pattern Recognition ,Computer Science - Machine Learning - Abstract
Surgical resections are the most prevalent curative treatment for primary liver cancer. Tumors located in critical positions are known to complexify liver resections (LR). While experienced surgeons in specialized medical centers may have the necessary expertise to accurately anticipate LR complexity, and prepare accordingly, an objective method able to reproduce this behavior would have the potential to improve the standard routine of care, and avoid intra- and postoperative complications. In this article, we propose CoRe, an automated medical image processing pipeline for the prediction of postoperative LR complexity from preoperative CT scans, using imaging biomarkers. The CoRe pipeline first segments the liver, lesions, and vessels with two deep learning networks. The liver vasculature is then pruned based on a topological criterion to define the hepatic central zone (HCZ), a convex volume circumscribing the major liver vessels, from which a new imaging biomarker, BHCZ is derived. Additional biomarkers are extracted and leveraged to train and evaluate a LR complexity prediction model. An ablation study shows the HCZ-based biomarker as the central feature in predicting LR complexity. The best predictive model reaches an accuracy, F1, and AUC of 77.3, 75.4, and 84.1% respectively., Comment: Accepted by the MIABID workshop at MICCAI 2022
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- 2022
12. Impact of second autologous stem‐cell transplantation at relapsed multiple myeloma: A French multicentric real‐life study
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Axel André, Lydia Montes, Damien Roos‐Weil, Laurent Frenzel, Marguerite Vignon, Thomas Chalopin, Pierre‐Edouard Debureaux, Alexis Talbot, Agathe Farge, Fabrice Jardin, Karim Belhadj, Bruno Royer, Jean‐Pierre Marolleau, Bertrand Arnulf, Pierre Morel, and Stéphanie Harel
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Diseases of the blood and blood-forming organs ,RC633-647.5 - Abstract
Abstract A second autologous stem‐cell transplantation (ASCT2) is considered for relapsed multiple myeloma (RMM) patients showing prolonged response after a first ASCT. However, given breakthrough treatments like anti‐CD38 and immunotherapy, its role remains debated. We conducted a real‐life study in 10 French centers (1996–2017) involving 267 RMM patients receiving ASCT2. The median age was 61 years, with 49% females. Most patients received melphalan 200 mg/m² before ASCT2, with low early mortality (1%). Very good partial response or better (VGPR+) rate post ASCT2 was 78%. Post ASCT2, 48% received consolidation therapy and 40% maintenance therapy. Median event‐free survival (EFS) after ASCT2 was 2.6 years (95% confidence interval [CI]: 2.3–2.8), and 2‐year EFS estimate was 63% (95% CI: 57–70). Median overall survival (OS) was 8.1 years (95% CI: 5.9–NA), and 2‐year OS estimate was 92% (95% CI: 88–95). Multivariate analysis revealed that VGPR+ status and maintenance therapy post ASCT2 were associated with better EFS (hazard ratio [HR]: 0.6; 95% CI: 0.3–0.9, p = 0.012 and HR: 0.4; 95% CI: 0.3–0.6, p
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- 2024
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13. Can Biomarkers Correctly Predict Ventilator-associated Pneumonia in Patients Treated With Targeted Temperature Management After Cardiac Arrest? An Exploratory Study of the Multicenter Randomized Antibiotic (ANTHARTIC) Study
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Nicolas Deye, MD, PhD, Amelie Le Gouge, MSc, Bruno François, MD, Camille Chenevier-Gobeaux, MD, PhD, Thomas Daix, MD, Hamid Merdji, MD, PhD, Alain Cariou, MD, PhD, Pierre-François Dequin, MD, PhD, Christophe Guitton, MD, Bruno Mégarbane, MD, PhD, Jacques Callebert, PharmD, PhD, Bruno Giraudeau, PhD, Alexandre Mebazaa, MD, PhD, Nicolas Vodovar, PhD, for the Clinical Research in Intensive Care and Sepsis-TRIal Group for Global Evaluation and Research in SEPsis (TRIGGERSEP) Network and the ANtibiotherapy during Therapeutic HypothermiA to pRevenT Infectious Complications (ANTHARTIC) Study Group, Arnaud Desachy, Christophe Cracco, Laurence Robin, Marie Anne Fally, David Schnell, Olivier Baudin, Charles Lafon, Philippe Petua, Stéphane Rouleau, Cyrille Nowak, Gaétan Plantefeve, Hervé Mentec, Olivier Pajot, Damien Contou, Jo-Anna Tirolien, Constance Vuillard, Cécile Zylberfajn, Nadile Ali, Dieudonne Kilendo, Olivia Chauvel, Elias Karam, Pascal Chevallier, Dorothée Ducoux, Fabrice Raymond, Christophe Gellis, Jean-Pierre Quenot, Thérèse Devaux, Audrey Large, Sébastien Mortreux, Pierre-Emmanuel Charles, Sébastien Prin, Jean-Baptiste Roudaut, Pascal Andreu, Auguste Dargent, Nora Perrot, Audrey Massard, Solenne Villot, Corinne Pernot, Bruno Francois, Thomas Daix, Philippe Vignon, Nicolas Pichon, Celine Gonzalez, Nicolas Rodier, Jean François Mary, Ludmila Baudrillart, Christine Vallejo, Emmanuelle Begot, Claire Mancia, Michelle Nouaille, Cécile Duchiron, Sandrine Naturel, Marie-Anne De Vinzellles, Hélène Beacco, Thierry Boulain, Chantal Brossard, Armelle Mathonnet, Dalila Benzekri-Lefevre, Anne Bretagnol, Isabelle Runge, François Barbier, Grégoire Muller, Mai-Anh Nay, Julie Rossi, Lucie Muller, Sophie Tollec, Alain Cariou, Nathalie Marin, Camille Chenevier-Gobeaux, Michel Arnaout, Omar Ben Hadj Salem, Wulfran Bougouin, Simon Bourcier, Benoit Champigneulle, Matthieu Jamme, Alexis Ferre, Guillaume Geri, Frédéric Pene, Julien Charpentier, Jean-Daniel Chiche, Lucie Guillemet, Jean-Paul Mira, Marine Paul, Nicolas Deye, Bruno Megarbane, Alexandre Mebazaa, Isabelle Malissin, Sebastian Voicu, Nicolas Vodovar, Jacques Callebert, Claire Pernin, Lydia Suarez, Philippe Manivet, Dominique Vodovar, Anthony Checinski, Lamia Kerdjana, Pierre Garcon, Antoine Goury, Catherine Fauvaux, Salamata Agne, Nahima Gueblaoui, Aude Jacob, Loic Chimot, Catherine Huchet, Nadège Lacoste, Pierre-Henri Dessalles, Mélanie Saint-Leger, Yannick Monseau, Marie Heil, Ferhat Meziani, Hamid Merdji, DrKhoury, Samir Chenaf, Christine Kummerlen, Yannick Rabouel, Hayat Allam, Anne Hutt-Clauss, Alexandra Monnier, Pierre-François Dequin, Christine Mabilat, Emmanuelle Rouve, Charlotte Salmon-Gandonnière, Denis Garot, Youen Jouan, Stephan Ehrmann, Antoine Guillon, Laetitia Bodet–Contentin, Emmanuelle Mercier, Julie Mankikian, Stéphane Legriel, MrSébastien Cavelot, Christophe Guitton, Charlotte Garret, Cédric Bretonniere, Laurent Nicolat, Noëlle Brule, and Olivier Zambon
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Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
IMPORTANCE:. Ventilator-associated pneumonia (VAP) frequently occurs in patients with cardiac arrest. Diagnosis of VAP after cardiac arrest remains challenging, while the use of current biomarkers such as C-reactive protein (CRP) or procalcitonin (PCT) is debated. OBJECTIVES:. To evaluate biomarkers’ impact in helping VAP diagnosis after cardiac arrest. DESIGN, SETTING, AND PARTICIPANTS:. This is a prospective ancillary study of the randomized, multicenter, double-blind placebo-controlled ANtibiotherapy during Therapeutic HypothermiA to pRevenT Infectious Complications (ANTHARTIC) trial evaluating the impact of antibiotic prophylaxis to prevent VAP in out-of-hospital patients with cardiac arrest secondary to shockable rhythm and treated with therapeutic hypothermia. An adjudication committee blindly evaluated VAP according to predefined clinical, radiologic, and microbiological criteria. All patients with available biomarker(s), sample(s), and consent approval were included. MAIN OUTCOMES AND MEASURES:. The main endpoint was to evaluate the ability of biomarkers to correctly diagnose and predict VAP within 48 hours after sampling. The secondary endpoint was to study the combination of two biomarkers in discriminating VAP. Blood samples were collected at baseline on day 3. Routine and exploratory panel of inflammatory biomarkers measurements were blindly performed. Analyses were adjusted on the randomization group. RESULTS:. Among 161 patients of the ANTHARTIC trial with available biological sample(s), patients with VAP (n = 33) had higher body mass index and Acute Physiology and Chronic Health Evaluation II score, more unwitnessed cardiac arrest, more catecholamines, and experienced more prolonged therapeutic hypothermia duration than patients without VAP (n = 121). In univariate analyses, biomarkers significantly associated with VAP and showing an area under the curve (AUC) greater than 0.70 were CRP (AUC = 0.76), interleukin (IL) 17A and 17C (IL17C) (0.74), macrophage colony-stimulating factor 1 (0.73), PCT (0.72), and vascular endothelial growth factor A (VEGF-A) (0.71). Multivariate analysis combining novel biomarkers revealed several pairs with p value of less than 0.001 and odds ratio greater than 1: VEGF-A + IL12 subunit beta (IL12B), Fms-related tyrosine kinase 3 ligands (Flt3L) + C–C chemokine 20 (CCL20), Flt3L + IL17A, Flt3L + IL6, STAM-binding protein (STAMBP) + CCL20, STAMBP + IL6, CCL20 + 4EBP1, CCL20 + caspase-8 (CASP8), IL6 + 4EBP1, and IL6 + CASP8. Best AUCs were observed for CRP + IL6 (0.79), CRP + CCL20 (0.78), CRP + IL17A, and CRP + IL17C. CONCLUSIONS AND RELEVANCE:. Our exploratory study shows that specific biomarkers, especially CRP combined with IL6, could help to better diagnose or predict early VAP occurrence in cardiac arrest patients.
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- 2024
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14. How I use ultrasound in cardiac arrest
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Wong, Adrian, Vignon, Philippe, and Robba, Chiara
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- 2023
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15. Right ventricular injury in patients with COVID-19-related ARDS eligible for ECMO support: a multicenter retrospective study
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Matthieu Petit, Misylias Bouaoud, Edouard Jullien, Adrien Joseph, Bruno Evrard, Cyril Charron, Anousone Daulasim, Annick Legras, Maeva Gourraud, Marine Goudelin, Philippe Vignon, and Antoine Vieillard-Baron
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Acute respiratory distress syndrome ,COVID-19 ,Right ventricle ,Extracorporeal membrane oxygenation ,Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Abstract Background Coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome (ARDS) is associated with high mortality. Extracorporeal membrane oxygenation (ECMO) has been proposed in this setting, but optimal criteria to select target patients remain unknown. Our hypothesis is that evaluation of right ventricular (RV) function could be helpful. The aims of our study were to report the incidence and outcomes of patients eligible for ECMO according to EOLIA criteria, and to identify a subgroup of patients with RV injury, which could be a target for ECMO. Methods Retrospective observational study involving 3 French intensive care units (ICUs) of teaching hospitals. Patients with confirmed SARS-CoV-2 infection between March 2020 and March 2021, presenting ARDS and with available echocardiography, were included. Patients were classified in three groups according to whether or not they met the EOLIA criteria and the presence of RV injury (RVI) (“EOLIA −”, “EOLIA + RVI −” and “EOLIA + RVI + ”). RVI was defined by the association of RV to left ventricular end-diastolic area ratio > 0.8 and paradoxical septal motion. Kaplan–Meier survival curves were used to analyze outcome as well as a Cox model for 90 day mortality. Results 915 patients were hospitalized for COVID-19, 418 of them with ARDS. A total of 283 patients with available echocardiography were included. Eighteen (6.3%) patients received ECMO. After exclusion of these patients, 107 (40.5%) were classified as EOLIA −, 126 (47.5%) as EOLIA + RVI −, and 32 (12%) as EOLIA + RVI + . Ninety-day mortality was 21% in the EOLIA-group, 44% in the EOLIA + RVI-group, and 66% in the EOLIA + RVI + group (p
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- 2024
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16. A 7-year record of vertical profiles of radar measurements and precipitation estimates at Dumont d'Urville, Adélie Land, East Antarctica
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V. Wiener, M.-L. Roussel, C. Genthon, É. Vignon, J. Grazioli, and A. Berne
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Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
Studying precipitation falling over Antarctica is crucial as snowfall represents the main water input term for the polar cap. However, precipitation observations still remain scarce – and, more particularly, in the atmospheric column – due to numerous experimental issues related to the white continent. This paper aims at helping to close this observation gap by presenting 7 years of Micro Rain Radar (Metek MRR-2) data at the Dumont d'Urville station in coastal Adélie Land, East Antarctica. Statistics are calculated on three radar variables (equivalent reflectivity, mean Doppler velocity and signal-to-noise ratio (SNR)) to outline the main characteristics of the radar dataset. Seasonal and interannual variabilities are also investigated, but no significant temporal trends are detected, except for the seasonal mean Doppler velocity, which is higher in summer and lower in winter. We then use the snowfall rate (S) data from a collocated snow gauge to estimate the MRR precipitation profile from the radar equivalent reflectivity (Ze) through a locally derived Ze–S relation. We find the relation Ze=43.3S0.88. The processing method used to obtain this relation, data quality and uncertainty considerations are discussed in the paper. In order to give an example of application of the dataset, a brief statistical comparison of the MRR precipitation rate along the vertical with model data from the ERA5 reanalysis and the LMDZ climate model is performed, which notably shows that models underestimate heavy precipitation events. All datasets are available on the PANGAEA database with the associated DOI: https://doi.org/10.1594/PANGAEA.962727 (Wiener et al., 2023).
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- 2024
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17. Transvaginal ultrasound and magnetic resonance imaging in the diagnosis of endometrioma: a systematic review and meta-analysis of diagnostic test accuracy studies
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Fleur Serge Kanti, Rose Gorak Savard, Frédéric Bergeron, Hervé Tchala Vignon Zomahoun, Antoine Netter, and Sarah Maheux-Lacroix
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Diagnostic test accuracy ,endometrioma ,endometriosis ,magnetic resonance imaging ,transvaginal ultrasound ,Gynecology and obstetrics ,RG1-991 - Abstract
Introduction The diagnosis of endometriomas in patients with endometriosis is of primary importance because it influences the management and prognosis of infertility and pain. Imaging techniques are evolving constantly. This study aimed to systematically assess the diagnostic accuracy of transvaginal ultrasound (TVUS) and magnetic resonance imaging (MRI) in detecting endometrioma using the surgical visualisation of lesions with or without histopathological confirmation as reference standards in patients of reproductive age with suspected endometriosis.Methods PubMed, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature and ClinicalTrials.gov databases were searched from their inception to 12 October 2022, using a manual search for additional articles. Two authors independently performed title, abstract and full-text screening of the identified records, extracted study details and quantitative data and assessed the quality of the studies using the ‘Quality Assessment of Diagnostic Accuracy Study 2’ tool. Bivariate random-effects models were used to determine the pooled sensitivity and specificity, compare the two imaging modalities and evaluate the sources of heterogeneity.Results Sixteen prospective studies (10 assessing TVUS, 4 assessing MRI and 2 assessing both TVUS and MRI) were included, representing 1976 participants. Pooled TVUS and MRI sensitivities for endometrioma were 0.89 (95% confidence interval ‘CI’, 0.86–0.92) and 0.94 (95% CI, 0.74–0.99), respectively (indirect comparison p-value of 0.47). Pooled TVUS and MRI specificities for endometrioma were 0.95 (95% CI, 0.92–0.97) and 0.94 (95% CI, 0.89–0.97), respectively (indirect comparison p-value of 0.51). These studies had a high or unclear risk of bias. A direct comparison (all participants undergoing TVUS and MRI) of the modalities was available in only two studies.Conclusion TVUS and MRI have high accuracy for diagnosing endometriomas; however, high-quality studies comparing the two modalities are lacking.
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- 2024
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18. Spatio-temporal dynamics of nutrients at the water-sediment interface: case of the Nokoue lagoon in Southern Benin
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Socohou, Akilou Amadou, Djihouessi, Metogbe Belfrid, Tigo, Béatrix Amen, Viainon, Vignon Mechtilde, Adandedji, Firmin Mahoutin, Adounpke, Julien, and AINA, Martin Pépin
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- 2024
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19. Phase retrieval for nilpotent groups
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Führ, Hartmut and Oussa, Vignon
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Mathematics - Representation Theory ,Mathematics - Functional Analysis ,42C15, 42A38, 65T50, 94A12 - Abstract
We study the phase retrieval property for orbits of general irreducible representations of nilpotent groups, for the classes of simply connected connected Lie groups, and for finite groups. We prove by induction that in the Lie group case, all irreducible representations do phase retrieval. For the finite group case, we mostly focus on $p$-groups. Here our main result states that every irreducible representation of an arbitrary $p$-group with exponent $p$ and size $\le p^{2+p/2}$ does phase retrieval. Despite the fundamental differences between the two settings, our inductive proof methods are remarkably similar., Comment: Revised version, correcting some insufficient assumptions made in the previous version. In particular, the general theorem about $p$-groups is only established for $p$-groups of exponent $p$
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- 2022
20. Recurrent/Metastatic Nasopharyngeal Carcinoma Treatment from Present to Future: Where Are We and Where Are We Heading?
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Juarez-Vignon Whaley, Juan Jose, Afkhami, Michelle, Onyshchenko, Mykola, Massarelli, Erminia, Sampath, Sagus, Amini, Arya, Bell, Diana, and Villaflor, Victoria M.
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- 2023
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21. Echocardiography phenotypes of right ventricular involvement in COVID-19 ARDS patients and ICU mortality: post-hoc (exploratory) analysis of repeated data from the ECHO-COVID study
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Huang, Stephen, Vieillard-Baron, Antoine, Evrard, Bruno, Prat, Gwenaël, Chew, Michelle S., Balik, Martin, Clau-Terré, Fernando, De Backer, Daniel, Mekontso Dessap, Armand, Orde, Sam, Morelli, Andrea, Sanfilippo, Filippo, Charron, Cyril, and Vignon, Philippe
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- 2023
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22. Epirubicin, cisplatin plus ifosfamide versus standard chemotherapeutic regimens for advanced/unresectable primary thoracic sarcomas
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Rodriguez-Cid, Jeronimo Rafael, Juarez-Vignon Whaley, Juan Jose, Sánchez-Domínguez, Gisela, Guzmán-Casta, Jordi, Carrasco-CaraChards, Sonia, Guzmán-Huesca, Jorge, Riera-Sala, Rodrigo, Sánchez-Ríos, Carla Paola, Cruz-Zermeño, Mayte, Seidman-Sorsby, Alec, de Jesús Rodríguez-Zea, Ivan, Alatorre-Alexander, Jorge Arturo, Martínez-Barrera, Luis Manuel, Santillán-Doherty, Patricio Javier, Godina-Flores, Aminadab, Imaz-Olguin, Victoria, Sosa-Sánchez, Ricardo, and Green-Renner, Dan
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- 2023
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23. Early Stage and Locally Advanced Nasopharyngeal Carcinoma Treatment from Present to Future: Where Are We and Where Are We Going?
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Juarez-Vignon Whaley, Juan Jose, Afkhami, Michelle, Sampath, Sagus, Amini, Arya, Bell, Diana, and Villaflor, Victoria M.
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- 2023
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24. Skin involvement in systemic lymphoma of follicular helper T‐cell origin: A cohort study of 57 patients
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Romain Stammler, Maxime Battistella, Julien Calvani, Baptiste Louveau, François Lemonnier, Saskia Ingen‐Housz Oro, Nicolas Ortonne, Jean David Bouaziz, Jacqueline Rivet, Marie‐Dominique Vignon‐Pennamen, David Boutboul, Caroline Ram‐Wolff, Lionel Galicier, Catherine Thieblemont, Pauline Brice, Loïc Renaud, Geraldine Jeudy, Marie Beylot‐Barry, Christian Le Clech, Charlée Nardin, Jean‐Michel Cayuela, Véronique Meignin, Samia Mourah, Martine Bagot, Adèle De Masson, and French Study Group on Cutaneous Lymphomas
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angioimmunoblastic T‐cell lymphoma ,cutaneous T‐cell lymphoma ,T follicular helper cells ,T follicular helper lymphoma ,Dermatology ,RL1-803 ,Diseases of the genitourinary system. Urology ,RC870-923 - Abstract
Abstract Background Angioimmunoblastic T‐cell lymphoma (AITL) is one of the most frequent peripheral T‐cell lymphomas (PTCL) in western countries. Skin involvement is common and may reveal the malignancy. Despite its frequency, skin involvement in AITL has been poorly described. Objectives We aimed to analyze the cutaneous expression of PTCL of TFH origin and its prognostic impact. Methods We conducted a multicenter retrospective cohort study by retrieving histopathological reports including the mention ‘AITL’ or ‘PTCL with T‐follicular helper phenotype’ (PTCL‐TFH) from five French tertiary hospital centers. Results From 2000 to 2022, we reviewed 382 histopathological records and identified 52 AITL cases and 5 PTCL‐TFH cases with cutaneous involvement. Thirty‐two (56%) patients were males with a mean age of 63 years. Fifty‐six (98%) patients presented with lymphadenopathy, 32 (56%) splenomegaly and 17 (30%) hepatomegaly. B signs were present in 34 (60%) patients. Skin lesions were present on the lower limbs in 44 (77%) patients, trunk in 38 (67%) patients, upper limbs in 35 (61%) and head in 27 (47%). Macules and papules were the most frequent lesions found in 47 (82%) patients, followed by nodules in 10 (17%) patients, erythemato‐squamous plaques in 10 (17%) patients, purpura in 9 (16%), urticaria in 9 (16%) and blisters in 5 (9%) patients. Erythroderma affected seven patients (12%). A skin biopsy was taken in 50 patients and revealed a specific lymphomatous infiltrate in 36 cases. A dominant skin T‐cell clone was detected in 13 out of 17 (76%) patients. Among the 14 patients with a nonspecific dermatitis, various histopathological patterns were observed including interface dermatitis, psoriasiform dermatitis, vasculitis, bullous dermatitis, granulomatous dermatitis and thrombotic vasculopathy. After a median follow‐up of 24 months (range, 0–121 months), median overall survival was 121 months (95% CI, 25.2–NA). At last follow‐up, 33 patients (58%) were alive, 20 (35%) were in complete remission and 7 (12%) were in partial remission; 30 (53%) patients experienced at least one relapse, including nodal relapses in 24 (80%) cases and cutaneous relapses in 12 (40%). Conclusions This study revealed the deep heterogeneity of skin presentations in AITL. Atypical skin presentations were common and included blistering, purpuric and psoriasiform eruptions.
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- 2023
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25. Development of a potency assay for CD34+ cell-based therapy
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Anne Aries, Christine Vignon, Céline Zanetti, Aurélien Goubaud, Arthur Cormier, Anne Diederichs, Rachid Lahlil, Philippe Hénon, and Ibon Garitaonandia
- Subjects
Medicine ,Science - Abstract
Abstract We have previously shown that intracardiac delivery of autologous CD34+ cells after acute myocardial infarction (AMI) is safe and leads to long term improvement. We are now conducting a multicenter, randomized, controlled Phase I/IIb study in post-AMI to investigate the safety and efficacy of intramyocardial injection of expanded autologous CD34+ cells (ProtheraCytes) (NCT02669810). Here, we conducted a series of in vitro studies characterizing the growth factor secretion, exosome secretion, gene expression, cell surface markers, differentiation potential, and angiogenic potential of ProtheraCytes clinical batches to develop a potency assay. We show that ProtheraCytes secrete vascular endothelial growth factor (VEGF) and its concentration is significantly correlated with the number of CD34+ cells obtained after expansion. ProtheraCytes also secrete exosomes containing proangiogenic miRNAs (126, 130a, 378, 26a), antiapoptotic miRNAs (21 and 146a), antifibrotic miRNAs (133a, 24, 29b, 132), and miRNAs promoting myocardial regeneration (199a and 590). We also show that ProtheraCytes have in vitro angiogenic activity, express surface markers of endothelial progenitor cells, and can differentiate in vitro into endothelial cells. After the in vitro characterization of multiple ProtheraCytes clinical batches, we established that measuring the concentration of VEGF provided the most practical, reliable, and consistent potency assay.
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- 2023
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26. Local spatial variability in the occurrence of summer precipitation in the Sør Rondane Mountains, Antarctica
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A. Ferrone, É. Vignon, A. Zonato, and A. Berne
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Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
During the austral summer 2019/2020, three vertically pointing K-band Doppler profilers (Micro Rain Radar PRO, MRR-PRO) were deployed along a transect across the Sør Rondane Mountains, directly south of the scientific base Princess Elisabeth Antarctica. The MRR-PRO devices were placed at locations corresponding to different stages of the interaction between the complex terrain and the typical flow associated with precipitating systems. The radar measurements, alongside information from the ERA5 reanalysis and a set of high-resolution Weather Research and Forecasting (WRF) simulations, have been used to study the spatial variability in snowfall across the transect. Radar observations reveal differences in the frequency of occurrence of virga and surface precipitation above the transect. An analysis of the WRF outputs reveals the presence of a relatively dry layer above the radar locations, reaching a constant altitude of 3.5 km above mean sea level. Due to the complex terrain, the depth of the layer varies across the transect, affecting sublimation and the occurrence of virgae. Combined information from the ERA5 reanalysis, the WRF simulations, and ground-level measurements suggests that orographic lifting enhances precipitation above the highest mountain peaks. Finally, the analysis of the succession of virga and surface precipitation above the sites shows that, in most cases, they represent different stages of the same large-scale events. This study reveals the significant spatial variability in the occurrence of precipitation in a region of complex terrain, emphasizing the importance of collecting snowfall measurements in the mountainous regions of the Antarctic continent.
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- 2023
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27. Importance of the advection scheme for the simulation of water isotopes over Antarctica by atmospheric general circulation models: A case study for present-day and Last Glacial Maximum with LMDZ-iso
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Cauquoin, Alexandre, Risi, Camille, and Vignon, Étienne
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Physics - Atmospheric and Oceanic Physics - Abstract
Atmospheric general circulation models (AGCMs) are known to have a warm and isotopically enriched bias over Antarctica. We test here the hypothesis that these biases are partly consequences of a too diffusive advection. Exploiting the LMDZ-iso model, we show that a less diffusive representation of the advection, especially on the horizontal, is very important to reduce the bias in the isotopic contents of precipitation above this area. The choice of an appropriate representation of the advection is thus essential when using GCMs for paleoclimate applications based on polar water isotopes. Too much diffusive mixing along the poleward transport leads to overestimated isotopic contents in water vapor because dehydration by mixing follows a more enriched path than dehydration by Rayleigh distillation. The near-air surface temperature is also influenced, to a lesser extent, by the diffusive properties of the advection scheme directly via the advection of the air and indirectly via the radiative effects of changes in high cloud fraction and water vapor. A too diffusive horizontal advection increases the temperature and so also contributes to enrich the isotopic contents of water vapor over Antarctica through a reduction of the distillation. The temporal relationship, from Last Glacial Maximum (LGM) to present-day conditions, between the mean annual near-air surface temperature and the water isotopic contents of precipitation for a specific location can also be impacted, with significant consequences on the paleo-temperature reconstruction from observed changes in water isotopes., Comment: Accepted paper version. See published version in EPSL Elsevier website
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- 2021
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28. The HRT conjecture for two classes of special configurations
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Okoudjou, Kasso A. and Oussa, Vignon
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Mathematics - Functional Analysis - Abstract
The HRT (Heil-Ramanathan-Topiwala) conjecture stipulates that the set of any finitely many time-frequency shifts of a non-zero square Lebesgue integrable function is linearly independent. The present work settles two special cases of this conjecture, namely, the cases where the set of time-frequency shifts has cardinality $N+1$ such that either $N$ of the points lie on some integer lattice and the last point is arbitrary, or $N$ of the points are on a line, while the last point does not belong this line. In both cases, we prove that the HRT conjecture holds appealing mainly to various forms of the ergodic theorem. We note that, in recent years, the latter case has been the subject of many investigations -- notably, the subcase where $N=3$ -- and our work completely resolves it., Comment: This revised manuscript on the HRT conjecture corrects a significant gap in the second case and provides a proof for the first case, focusing on a configuration of n points on an integer lattice and one off-lattice point. A decay condition is also imposed on the window vector
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- 2021
29. Phase retrieval for affine groups over prime fields
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Bartusel, David, Führ, Hartmut, and Oussa, Vignon
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Mathematics - Representation Theory ,42C15, 42A38, 94A12, 20B20 - Abstract
We study phase retrieval for group frames arising from permutation representations, focusing on the action of the affine group of a finite field. We investigate various versions of the phase retrieval problem, including conjugate phase retrieval, sign retrieval, and matrix recovery. Our main result establishes that the canonical irreducible representation of the affine group $\mathbb{Z}_p \rtimes \mathbb{Z}_p^\ast$ (with $p$ prime), acting on the vectors in $\mathbb{C}^{p}$ with zero-sum, has the strongest retrieval property, allowing to reconstruct matrices from scalar products with a group orbit consisting of rank-one projections. We explicitly characterize the generating vectors that ensure this property, provide a linear matrix recovery algorithm and explicit examples of vectors that allow matrix recovery. We also comment on more general permutation representations., Comment: Slightly updated file, but no substantial changes
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- 2021
30. Multiscale modelling of reversed Potts shunt as a potential palliative treatment for suprasystemic idiopathic pulmonary artery hypertension in children
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Pant, Sanjay, Sizarov, Aleksander, Knepper1, Angela, Gossard, Gaetan, Noferi, Alberto, Boudjemline, Younes, and Vignon-Clementel, Irene
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Physics - Medical Physics ,Physics - Fluid Dynamics - Abstract
Reversed Potts shunt (PS) was suggested as palliation for patients with suprasystemic pulmonary arterial hypertension (PAH) and right ventricular (RV) failure. PS, however, can result in poorly understood mortality. Here, a patient-specific geometrical multiscale model of PAH physiology and PS is developed for a paediatric PAH patient with stent-based PS. In the model, 7.6mm-diameter PS produces near-equalisation of the aortic and PA pressures and Qp/Qs (oxygenated vs deoxygenated blood flow) ratio of 0.72 associated with a 16% decrease of left ventricular (LV) output and 18% increase of RV output. The flow from LV to aortic arch branches increases by 16%, while LV contribution to the lower body flow decreases by 29%. Total flow in the descending aorta (DAo) increases by 18% due to RV contribution through the PS with flow into the distal PA branches decreasing. PS induces 18% increase of RV work due to its larger stroke volume pumped against lower afterload. Nonetheless, larger RV work does not lead to increased RV end-diastolic volume. Three-dimensional flow assessment demonstrates the PS jet impinging with a high velocity and wall shear stress on the opposite DAo wall with the most of the shunt flow being diverted to the DAo. Increasing the PS diameter from 5mm up to 10mm results in nearly linear decrease in post-operative Qp/Qs ratio. In conclusion, this model reasonably represents patient-specific haemodynamics pre- and post-creation of the PS, providing insights into physiology of this complex condition, and presents a predictive tool that could be useful for clinical decision-making regarding suitability for reversed PS in PAH patients with drug-resistant suprasystemic PAH., Comment: 46 pages, 30 Figures, 13 Tables
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- 2021
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31. Prevalence and impact of Eustachian valve on the diagnosis of patent foramen ovale in patients ventilated for an acute respiratory distress syndrome
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Sanchez, Florence, Goudelin, Marine, Evrard, Bruno, and Vignon, Philippe
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- 2023
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32. Development of a potency assay for CD34+ cell-based therapy
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Aries, Anne, Vignon, Christine, Zanetti, Céline, Goubaud, Aurélien, Cormier, Arthur, Diederichs, Anne, Lahlil, Rachid, Hénon, Philippe, and Garitaonandia, Ibon
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- 2023
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33. Diagnostic, prognostic and clinical value of left ventricular radial strain to identify paradoxical septal motion in ventilated patients with the acute respiratory distress syndrome: an observational prospective multicenter study
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Evrard, Bruno, Woillard, Jean-Baptiste, Legras, Annick, Bouaoud, Misylias, Gourraud, Maeva, Humeau, Antoine, Goudelin, Marine, and Vignon, Philippe
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- 2023
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34. Long-term immunosuppressive treatment is not associated with worse outcome in patients hospitalized in the intensive care unit for septic shock: the PACIFIC study
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Vaidie, Julien, Peju, Edwige, Jandeaux, Louise-Marie, Lesouhaitier, Mathieu, Lacherade, Jean-Claude, Guillon, Antoine, Wittebole, Xavier, Asfar, Pierre, Evrard, Bruno, Daix, Thomas, Vignon, Philippe, and François, Bruno
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- 2023
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35. Genome-wide analysis of a collective grave from Mentesh Tepe provides insight into the population structure of early neolithic population in the South Caucasus
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Guarino-Vignon, Perle, Lefeuvre, Maël, Chimènes, Amélie, Monnereau, Aurore, Guliyev, Farhad, Pecqueur, Laure, Jovenet, Elsa, Lyonnet, Bertille, and Bon, Céline
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- 2023
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36. Overexpression of GPX2 gene regulates the development of porcine preadipocytes and skeletal muscle cells through MAPK signaling pathway.
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Chunguang Zhang, Lei Wang, Lei Qin, Yunyan Luo, Zuochen Wen, Akpaca Samson Vignon, Chunting Zheng, Xueli Zhu, Han Chu, Shifan Deng, Liang Hong, Jianbin Zhang, Hua Yang, Jianbo Zhang, Yuhong Ma, Guofang Wu, Chao Sun, Xin Liu, and Lei Pu
- Subjects
Medicine ,Science - Abstract
Glutathione peroxidase 2 (GPX2) is a selenium-dependent enzyme and protects cells against oxidative damage. Recently, GPX2 has been identified as a candidate gene for backfat and feed efficiency in pigs. However, it is unclear whether GPX2 regulates the development of porcine preadipocytes and skeletal muscle cells. In this study, adenoviral gene transfer was used to overexpress GPX2. Our findings suggest that overexpression of GPX2 gene inhibited proliferation of porcine preadipocytes. And the process is accompanied by the reduction of the p-p38. GPX2 inhibited adipogenic differentiation and promoted lipid degradation, while ERK1/2 was reduced and p-p38 was increased. Proliferation of porcine skeletal muscle cells was induced after GPX2 overexpression, was accompanied by activation in JNK, ERK1/2, and p-p38. Overexpression methods confirmed that GPX2 has a promoting function in myoblastic differentiation. ERK1/2 pathway was activated and p38 was suppressed during the process. This study lays a foundation for the functional study of GPX2 and provides theoretical support for promoting subcutaneous fat reduction and muscle growth.
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- 2024
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37. Primary cutaneous follicle centre lymphoma with secondary systemic evolution
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Andy Li, Jacqueline Lehmann‐Che, Jérôme Champ, Jacqueline Rivet, Marie‐Dominique Vignon‐Pennamen, Samia Mourah, Jean‐Michel Cayuela, Clémence Lepelletier, Baptiste Louveau, Maëlle Dumont, Jana Alhage, Caroline Ram‐Wolff, Jean‐David Bouaziz, Martine Bagot, Adèle De Masson, and Maxime Battistella
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B‐cell lymphoma ,cutaneous follicle centre lymphoma ,cutaneous lymphoma ,Dermatology ,RL1-803 ,Diseases of the genitourinary system. Urology ,RC870-923 - Abstract
Abstract Primary cutaneous follicle centre lymphomas (PCFCLs) are cutaneous proliferation of centrocytes and centroblasts, with a generally indolent evolution. Secondary systemic spread of disease is a rare event, which significantly impairs prognosis. Recently published study by Zhou and al. proposed criteria aiming to predict such evolution at initial stage: (i) rearrangement of Bcl2, (ii) Ki67% index 30% Ki67% indexes and no mutations among the four proposed genes. These findings run contrary to these previously proposed criteria, highlighting the molecular heterogeneity of this rare disease.
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- 2023
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38. Long-term immunosuppressive treatment is not associated with worse outcome in patients hospitalized in the intensive care unit for septic shock: the PACIFIC study
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Julien Vaidie, Edwige Peju, Louise-Marie Jandeaux, Mathieu Lesouhaitier, Jean-Claude Lacherade, Antoine Guillon, Xavier Wittebole, Pierre Asfar, Bruno Evrard, Thomas Daix, Philippe Vignon, and Bruno François
- Subjects
Septic shock ,Intensive care unit ,Immunosuppression therapy ,Organ transplantation ,Autoimmune diseases ,Mortality ,Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Abstract Background Except in a few retrospective studies mainly including patients under chemotherapy, information regarding the impact of immunosuppressive therapy on the prognosis of patients admitted to the intensive care unit (ICU) for septic shock is scarce. Accordingly, the PACIFIC study aimed to asses if immunosuppressive therapy is associated with an increased mortality in patients admitted to the ICU for septic shock. Methods This was a retrospective epidemiological multicentre study. Eight high enroller centres in septic shock randomised controlled trials (RCTs) participated in the study. Patients in the “exposed” group were selected from the screen failure logs of seven recent RCTs and excluded because of immunosuppressive treatment. The “non-exposed” patients were those included in the placebo arm of the same RCTs. A multivariate logistic regression model was used to estimate the risk of death. Results Among the 433 patients enrolled, 103 were included in the “exposed” group and 330 in the “non-exposed” group. Reason for immunosuppressive therapy included organ transplantation (n = 45 [44%]) or systemic disease (n = 58 [56%]). ICU mortality rate was 24% in the “exposed” group and 25% in the “non-exposed” group (p = 0.9). Neither in univariate nor in multivariate analysis immunosuppressive therapy was associated with a higher ICU mortality (OR: 0.95; [95% CI 0.56–1.58]: p = 0.86 and 1.13 [95% CI 0.61–2.05]: p = 0.69, respectively) or 3-month mortality (OR: 1.13; [95% CI 0.69–1.82]: p = 0.62 and OR: 1.36 [95% CI 0.78–2.37]: p = 0.28, respectively). Conclusions In this study, long-term immunosuppressive therapy excluding chemotherapy was not associated with significantly higher or lower ICU and 3-month mortality in patients admitted to the ICU for septic shock.
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- 2023
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39. A Chinese–French Study on Nuclear Energy and the Environment
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Xiangeng Zhao, Qizhen Ye, Sébastien Candel, Dominique Vignon, and Robert Guillaumont
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Nuclear energy ,Environmental impact ,Radwaste management ,Severe nuclear accidents ,Nuclear safety ,Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
This article focuses on the environmental impact of nuclear energy and addresses the following major environmental issues associated with nuclear power generation: ① controlling the radioactive discharge from nuclear installations under normal operation and evaluating their non-radioactive environmental impact (water withdrawals and non-radioactive discharges); ② long-term management of spent fuel and radioactive waste (radwaste), notably that disposed off in geological repositories; ③ prevention and mitigation of severe nuclear accidents and their radioactive releases and; ④ improving nuclear safety to restrict its environmental impact and to contribute toward the public acceptance of nuclear energy. Nuclear energy, with its very low emissions of green house gases, has a unique capacity to generate massive and on-demand dispatchable amounts of electricity. The annual effective radiation dose delivered to the public surrounding nuclear power plants under normal operation is negligible. Considerable efforts have been made to define sustainable management of high-level long-lived radwaste that is disposed in geological formations. The return of experience from severe nuclear accidents in the past has informed and propelled major improvements in several aspects of nuclear energy production—including reactor design and operational management as well as in the development of accident-management guidelines—and has proved to be highly valuable. The environmental risks in the event of a severe accident have been substantially reduced and protocols have been established to minimize the release of radioactive materials and avoid the large-scale evacuation of people in the event of a severe nuclear accident. Efforts must be continued to improve reactor safety and enhance the transparency of the industry and the authorities that support and control nuclear power to further reduce the environmental impact.
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- 2023
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40. Trait variation in a successful global invader: a large-scale analysis of morphological variance and integration in the brown trout
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Vignon, Matthias, Zhou, Mingsha, McIntosh, Angus R., Correa, Cristian, Westley, Peter A. H., Jacquin, Lisa, Labonne, Jacques, and Hendry, Andrew P.
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- 2023
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41. Diffusion-weighted MRI-guided needle biopsies permit quantitative tumor heterogeneity assessment and cell load estimation
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Yin, Yi, Breuhahn, Kai, Kauczor, Hans-Ulrich, Sedlaczek, Oliver, Vignon-Clementel, Irene E., and Drasdo, Dirk
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Electrical Engineering and Systems Science - Image and Video Processing ,Physics - Medical Physics - Abstract
Quantitative information on tumor heterogeneity and cell load could assist in designing effective and refined personalized treatment strategies. It was recently shown by us that such information can be inferred from the diffusion parameter D derived from the diffusion-weighted MRI (DWI) if a relation between D and cell density can be established. However, such relation cannot a priori be assumed to be constant for all patients and tumor types. Hence to assist in clinical decisions in palliative settings, the relation needs to be established without tumor resection. It is here demonstrated that biopsies may contain sufficient information for this purpose if the localization of biopsies is chosen as systematically elaborated in this paper. A superpixel-based method for automated optimal localization of biopsies from the DWI D-map is proposed. The performance of the DWI-guided procedure is evaluated by extensive simulations of biopsies. Needle biopsies yield sufficient histological information to establish a quantitative relationship between D-value and cell density, provided they are taken from regions with high, intermediate, and low D-value in DWI. The automated localization of the biopsy regions is demonstrated from a NSCLC patient tumor. In this case, even two or three biopsies give a reasonable estimate. Simulations of needle biopsies under different conditions indicate that the DWI-guidance highly improves the estimation results. Tumor cellularity and heterogeneity in solid tumors may be reliably investigated from DWI and a few needle biopsies that are sampled in regions of well-separated D-values, excluding adipose tissue. This procedure could provide a way of embedding in the clinical workflow assistance in cancer diagnosis and treatment based on personalized information.
- Published
- 2021
42. Introducing the Hidden Neural Markov Chain framework
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Azeraf, Elie, Monfrini, Emmanuel, Vignon, Emmanuel, and Pieczynski, Wojciech
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Computer Science - Computation and Language ,Computer Science - Machine Learning - Abstract
Nowadays, neural network models achieve state-of-the-art results in many areas as computer vision or speech processing. For sequential data, especially for Natural Language Processing (NLP) tasks, Recurrent Neural Networks (RNNs) and their extensions, the Long Short Term Memory (LSTM) network and the Gated Recurrent Unit (GRU), are among the most used models, having a "term-to-term" sequence processing. However, if many works create extensions and improvements of the RNN, few have focused on developing other ways for sequential data processing with neural networks in a "term-to-term" way. This paper proposes the original Hidden Neural Markov Chain (HNMC) framework, a new family of sequential neural models. They are not based on the RNN but on the Hidden Markov Model (HMM), a probabilistic graphical model. This neural extension is possible thanks to the recent Entropic Forward-Backward algorithm for HMM restoration. We propose three different models: the classic HNMC, the HNMC2, and the HNMC-CN. After describing our models' whole construction, we compare them with classic RNN and Bidirectional RNN (BiRNN) models for some sequence labeling tasks: Chunking, Part-Of-Speech Tagging, and Named Entity Recognition. For every experiment, whatever the architecture or the embedding method used, one of our proposed models has the best results. It shows this new neural sequential framework's potential, which can open the way to new models, and might eventually compete with the prevalent BiLSTM and BiGRU., Comment: 13 pages, 4 figures, 4 tables, ICAART 2021
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- 2021
43. Highly Fast Text Segmentation With Pairwise Markov Chains
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Azeraf, Elie, Monfrini, Emmanuel, Vignon, Emmanuel, and Pieczynski, Wojciech
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Computer Science - Computation and Language ,Computer Science - Machine Learning - Abstract
Natural Language Processing (NLP) models' current trend consists of using increasingly more extra-data to build the best models as possible. It implies more expensive computational costs and training time, difficulties for deployment, and worries about these models' carbon footprint reveal a critical problem in the future. Against this trend, our goal is to develop NLP models requiring no extra-data and minimizing training time. To do so, in this paper, we explore Markov chain models, Hidden Markov Chain (HMC) and Pairwise Markov Chain (PMC), for NLP segmentation tasks. We apply these models for three classic applications: POS Tagging, Named-Entity-Recognition, and Chunking. We develop an original method to adapt these models for text segmentation's specific challenges to obtain relevant performances with very short training and execution times. PMC achieves equivalent results to those obtained by Conditional Random Fields (CRF), one of the most applied models for these tasks when no extra-data are used. Moreover, PMC has training times 30 times shorter than the CRF ones, which validates this model given our objectives., Comment: 9 pages, 5 figures, 4 tables, MNLP 2020
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- 2021
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44. Sensitivity Analysis of a Mathematical Model Simulating the Post-Hepatectomy Hemodynamics Response
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Sala, Lorenzo, Golse, Nicolas, Joosten, Alexandre, Vibert, Eric, and Vignon-Clementel, Irene
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- 2023
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45. On exponential bases and frames with non-linear phase functions and some applications
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Gabardo, Jean-Pierre, Lai, Chun-Kit, and Oussa, Vignon
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Mathematics - Functional Analysis ,42C15 - Abstract
In this paper, we study the spectrality and frame-spectrality of exponential systems of the type $E(\Lambda,\varphi) = \{e^{2\pi i \lambda\cdot\varphi(x)}: \lambda\in\Lambda\}$ where the phase function $\varphi$ is a Borel measurable which is not necessarily linear. A complete characterization of pairs $(\Lambda,\varphi)$ for which $E(\Lambda,\varphi)$ is an orthogonal basis or a frame for $L^{2}(\mu)$ is obtained. In particular, we show that the middle-third Cantor measures and the unit disc, each admits an orthogonal basis with a certain non-linear phase. Under a natural regularity condition on the phase functions, when $\mu$ is the Lebesgue measure on $[0,1]$ and $\Lambda= {\mathbb{Z}},$ we show that only the standard phase functions $\varphi(x) = \pm x$ are the only possible functions that give rise to orthonormal bases. Surprisingly, however we prove that there exist a greater degree of flexibility, even for continuously differentiable phase functions in higher dimensions. For instance, we were able to describe a large class of functions $\varphi$ defined on ${\mathbb{R}}^{d}$ such that the system $E(\Lambda,\varphi)$ is an orthonormal basis for $L^{2}[0,1]^{d}$ when $d\geq2.$ Moreover, we discuss how our results apply to the discretization problem of unitary representations of locally compact groups for the construction of orthonormal bases. Finally, we conclude the paper by stating several open problems.
- Published
- 2020
46. Hidden Markov Chains, Entropic Forward-Backward, and Part-Of-Speech Tagging
- Author
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Azeraf, Elie, Monfrini, Emmanuel, Vignon, Emmanuel, and Pieczynski, Wojciech
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Statistics - Machine Learning ,Computer Science - Computation and Language ,Computer Science - Machine Learning - Abstract
The ability to take into account the characteristics - also called features - of observations is essential in Natural Language Processing (NLP) problems. Hidden Markov Chain (HMC) model associated with classic Forward-Backward probabilities cannot handle arbitrary features like prefixes or suffixes of any size, except with an independence condition. For twenty years, this default has encouraged the development of other sequential models, starting with the Maximum Entropy Markov Model (MEMM), which elegantly integrates arbitrary features. More generally, it led to neglect HMC for NLP. In this paper, we show that the problem is not due to HMC itself, but to the way its restoration algorithms are computed. We present a new way of computing HMC based restorations using original Entropic Forward and Entropic Backward (EFB) probabilities. Our method allows taking into account features in the HMC framework in the same way as in the MEMM framework. We illustrate the efficiency of HMC using EFB in Part-Of-Speech Tagging, showing its superiority over MEMM based restoration. We also specify, as a perspective, how HMCs with EFB might appear as an alternative to Recurrent Neural Networks to treat sequential data with a deep architecture., Comment: 5 pages, 2 figures, 1 table
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- 2020
47. Heavy-tailed Representations, Text Polarity Classification & Data Augmentation
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Jalalzai, Hamid, Colombo, Pierre, Clavel, Chloé, Gaussier, Eric, Varni, Giovanna, Vignon, Emmanuel, and Sabourin, Anne
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Statistics - Machine Learning ,Computer Science - Computation and Language ,Computer Science - Machine Learning - Abstract
The dominant approaches to text representation in natural language rely on learning embeddings on massive corpora which have convenient properties such as compositionality and distance preservation. In this paper, we develop a novel method to learn a heavy-tailed embedding with desirable regularity properties regarding the distributional tails, which allows to analyze the points far away from the distribution bulk using the framework of multivariate extreme value theory. In particular, a classifier dedicated to the tails of the proposed embedding is obtained which performance outperforms the baseline. This classifier exhibits a scale invariance property which we leverage by introducing a novel text generation method for label preserving dataset augmentation. Numerical experiments on synthetic and real text data demonstrate the relevance of the proposed framework and confirm that this method generates meaningful sentences with controllable attribute, e.g. positive or negative sentiment.
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- 2020
48. Guider l'attention dans les modeles de sequence a sequence pour la prediction des actes de dialogue
- Author
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Colombo, Pierre, Chapuis, Emile, Manica, Matteo, Vignon, Emmanuel, Varni, Giovanna, and Clavel, Chloe
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Computer Science - Computation and Language - Abstract
The task of predicting dialog acts (DA) based on conversational dialog is a key component in the development of conversational agents. Accurately predicting DAs requires a precise modeling of both the conversation and the global tag dependencies. We leverage seq2seq approaches widely adopted in Neural Machine Translation (NMT) to improve the modelling of tag sequentiality. Seq2seq models are known to learn complex global dependencies while currently proposed approaches using linear conditional random fields (CRF) only model local tag dependencies. In this work, we introduce a seq2seq model tailored for DA classification using: a hierarchical encoder, a novel guided attention mechanism and beam search applied to both training and inference. Compared to the state of the art our model does not require handcrafted features and is trained end-to-end. Furthermore, the proposed approach achieves an unmatched accuracy score of 85% on SwDA, and state-of-the-art accuracy score of 91.6% on MRDA., Comment: in French
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- 2020
49. Guiding attention in Sequence-to-sequence models for Dialogue Act prediction
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Colombo, Pierre, Chapuis, Emile, Manica, Matteo, Vignon, Emmanuel, Varni, Giovanna, and Clavel, Chloe
- Subjects
Computer Science - Computation and Language ,Computer Science - Machine Learning - Abstract
The task of predicting dialog acts (DA) based on conversational dialog is a key component in the development of conversational agents. Accurately predicting DAs requires a precise modeling of both the conversation and the global tag dependencies. We leverage seq2seq approaches widely adopted in Neural Machine Translation (NMT) to improve the modelling of tag sequentiality. Seq2seq models are known to learn complex global dependencies while currently proposed approaches using linear conditional random fields (CRF) only model local tag dependencies. In this work, we introduce a seq2seq model tailored for DA classification using: a hierarchical encoder, a novel guided attention mechanism and beam search applied to both training and inference. Compared to the state of the art our model does not require handcrafted features and is trained end-to-end. Furthermore, the proposed approach achieves an unmatched accuracy score of 85% on SwDA, and state-of-the-art accuracy score of 91.6% on MRDA.
- Published
- 2020
50. Phase Retrieval for Nilpotent Groups
- Author
-
Führ, Hartmut and Oussa, Vignon
- Published
- 2023
- Full Text
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