Implication de l'ostéopontine dans le pathomécanisme de la scoliose idiopathique de l'adolescent

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Abstract

Recent work on learning multilingual word representations usually relies on the use of word-level alignements (e.g. infered with the help of GIZA++) between translated sentences, in order to align the word embeddings in different languages. In this workshop paper, we investigate an autoencoder model for learning multilingual word representations that does without such word-level alignements. The autoencoder is trained to reconstruct the bag-of-word representation of given sentence from an encoded representation extracted from its translation. We evaluate our approach on a multilingual document classification task, where labeled data is available only for one language (e.g. English) while classification must be performed in a different language (e.g. French). In our experiments, we observe that our method compares favorably with a previously proposed method that exploits word-level alignments to learn word representations.

Biomechanical simulations of the scoliotic deformation process in the pinealectomized chicken: a preliminary study

<p>Abstract</p> <p>Background</p> <p>The basic mechanisms whereby mechanical factors modulate the metabolism of the growing spine remain poorly understood, especially the role of growth adaptation in spinal disorders like in adolescent idiopathic scoliosis (AIS). This paper presents a finite element model (FEM) that was developed to simulate early stages of scoliotic deformities progression using a pinealectomized chicken as animal model.</p> <p>Methods</p> <p>The FEM includes basic growth and growth modulation created by the muscle force imbalance. The experimental data were used to adapt a FEM previously developed to simulate the scoliosis deformation process in human. The simulations of the spine deformation process are compared with the results of an experimental study including a group of pinealectomized chickens.</p> <p>Results</p> <p>The comparison of the simulation results of the spine deformation process (Cobb angle of 37°) is in agreement with experimental scoliotic deformities of two representative cases (Cobb angle of 41° and 30°). For the vertebral wedging, a good agreement is also observed between the calculated (28°) and the observed (25° – 30°) values.</p> <p>Conclusion</p> <p>The proposed biomechanical model presents a novel approach to realistically simulate the scoliotic deformation process in pinealectomized chickens and investigate different parameters influencing the progression of scoliosis.</p

Microvesicles in vascular homeostasis and diseases. Position Paper of the European Society of Cardiology (ESC) Working Group on Atherosclerosis and Vascular Biology

Microvesicles are members of the family of extracellular vesicles shed from the plasma membrane of activated or apoptotic cells. Microvesicles were initially characterised by their pro-coagulant activity and described as "microparticles". There is mounting evidence revealing a role for microvesicles in intercellular communication, with particular relevance to hemostasis and vascular biology. Coupled with this, the potential of microvesicles as meaningful biomarkers is under intense investigation. This Position Paper will summarise the current knowledge on the mechanisms of formation and composition of microvesicles of endothelial, platelet, red blood cell and leukocyte origin. This paper will also review and discuss the different methods used for their analysis and quantification, will underline the potential biological roles of these vesicles with respect to vascular homeostasis and thrombosis and define important themes for future research

Early mobilisation in critically ill COVID-19 patients: a subanalysis of the ESICM-initiated UNITE-COVID observational study

Background Early mobilisation (EM) is an intervention that may improve the outcome of critically ill patients. There is limited data on EM in COVID-19 patients and its use during the first pandemic wave. Methods This is a pre-planned subanalysis of the ESICM UNITE-COVID, an international multicenter observational study involving critically ill COVID-19 patients in the ICU between February 15th and May 15th, 2020. We analysed variables associated with the initiation of EM (within 72 h of ICU admission) and explored the impact of EM on mortality, ICU and hospital length of stay, as well as discharge location. Statistical analyses were done using (generalised) linear mixed-effect models and ANOVAs. Results Mobilisation data from 4190 patients from 280 ICUs in 45 countries were analysed. 1114 (26.6%) of these patients received mobilisation within 72 h after ICU admission; 3076 (73.4%) did not. In our analysis of factors associated with EM, mechanical ventilation at admission (OR 0.29; 95% CI 0.25, 0.35; p = 0.001), higher age (OR 0.99; 95% CI 0.98, 1.00; p ≤ 0.001), pre-existing asthma (OR 0.84; 95% CI 0.73, 0.98; p = 0.028), and pre-existing kidney disease (OR 0.84; 95% CI 0.71, 0.99; p = 0.036) were negatively associated with the initiation of EM. EM was associated with a higher chance of being discharged home (OR 1.31; 95% CI 1.08, 1.58; p = 0.007) but was not associated with length of stay in ICU (adj. difference 0.91 days; 95% CI − 0.47, 1.37, p = 0.34) and hospital (adj. difference 1.4 days; 95% CI − 0.62, 2.35, p = 0.24) or mortality (OR 0.88; 95% CI 0.7, 1.09, p = 0.24) when adjusted for covariates. Conclusions Our findings demonstrate that a quarter of COVID-19 patients received EM. There was no association found between EM in COVID-19 patients' ICU and hospital length of stay or mortality. However, EM in COVID-19 patients was associated with increased odds of being discharged home rather than to a care facility. Trial registration ClinicalTrials.gov: NCT04836065 (retrospectively registered April 8th 2021)

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Augmentation et génération de données d'apprentissage en traitement automatique des langues

More and more fields are looking to automate part of their process.Automatic language processing contains methods for extracting information from texts.These methods can use machine learning.Machine learning requires annotated data to perform information extraction.Applying these methods to new domains requires obtaining annotated data related to the task.In this thesis, our goal is to study generation methods to improve the performance of learned models with low amounts of data.Different methods of generation are explored that either contain machine learning or do not, which are used to generate the data needed to learn sequence labeling models.The first method explored is pattern filling.This data generation method generates annotated data by combining sentences with slots, or patterns, with mentions.We have shown that this method improves the performance of labeling models with tiny amounts of data.The amount of data needed to use this method is also studied.The second approach tested is the use of language models for text generation alongside a semi-supervised learning method for tagging.The semi-supervised learning method used is tri-training and is used to add labels to the generated data.The tri-training is tested on several generation methods using different pre-trained language models.We proposed a version of tri-training called generative tri-training, where the generation is not done in advance but during the tri-training process and takes advantage of it.The performance of the models trained during the semi-supervision process and of the models trained on the data generated by it are tested.In most cases, the data produced match the performance of the models trained with the semi-supervision.This method allows the improvement of the performances at all the tested data levels with respect to the models without augmentation.The third avenue of study combines some aspects of the previous approaches.For this purpose, different approaches are tested.The use of language models to do sentence replacement in the manner of the pattern-filling generation method is unsuccessful.Using a set of data coming from the different generation methods is tested, which does not outperform the best method.Finally, applying the pattern-filling method to the data generated with the tri-training is tested and does not improve the results obtained with the tri-training.While much remains to be studied, we have highlighted simple methods, such as pattern filling, and more complex ones, such as the use of supervised learning with sentences generated by a language model, to improve the performance of labeling models through the generation of annotated data.De plus en plus de domaines cherchent à automatiser une partie de leur processus.Le traitement automatique des langues contient des méthodes permettant d'extraire des informations dans des textes.Ces méthodes peuvent utiliser de l'apprentissage automatique.L'apprentissage automatique nécessite des données annotées pour faire de l'extraction d'information de manière optimale.L'application de ces méthodes à de nouveaux domaines nécessite d'obtenir des données annotées liée à la tâche.Le problème que nous souhaitons résoudre est de proposer et d'étudier des méthodes de génération pour améliorer les performances de modèles appris à basse quantité de données.Nous explorons différentes méthodes avec et sans apprentissage pour générer les données nécessaires à l'apprentissage de modèles d'étiquetage.La première méthode que nous explorons est le remplissage de patrons.Cette méthode de génération de données permet de générer des données annotées en combinant des phrases à trous, les patrons, et des mentions.Nous avons montré que cette méthode permet d'améliorer les performances des modèles d'étiquetage à très petite quantité de données.Nous avons aussi étudié la quantité de données nécessaire pour l'utilisation optimale de cette méthode.La deuxième approche de génération que nous avons testé est l'utilisation de modèles de langue pour la génération couplée à l'utilisation de méthode d'apprentissage semi-supervisé.La méthode d'apprentissage semi-supervisé utilisé est le tri-training et sert à ajouter les étiquettes aux données générées.Le tri-training est testé sur plusieurs méthodes de génération utilisant différents modèles de langue pré-entraînés.Nous avons proposé une version du tri-training appelé tri-training génératif, où la génération n'est pas faite en amont, mais durant le processus de tri-training et profite de celui-ci.Nous avons testé les performances des modèles entraînés durant le processus de semi-supervision et des modèles entraîné sur les données produites par celui-ci.Dans la majeure partie des cas, les données produites permettent d'égaler les performances des modèles entraînés avec la semi-supervision.Cette méthode permet l'amélioration des performances à tous les niveaux de données testés vis-à-vis des modèles sans augmentation.La troisième piste d'étude vise à combiner certains aspects des approches précédentes.Pour cela, nous avons testé différentes approches.L'utilisation de modèles de langues pour faire du remplacement de bouts de phrase à la manière de la méthode de remplissage de patrons fut infructueuse.Nous avons testé l'addition de données générées par différentes méthodes qui ne permet pas de surpasser la meilleure des méthodes.Enfin, nous avons testé l'application de la méthode de remplissage de patrons sur les données générées avec le tri-training qui n'a pas amélioré les résultats obtenu avec le tri-training.S'il reste encore beaucoup à étudier, nous avons cependant mis en évidence des méthodes simples, comme le remplissage de patrons, et plus complexe, comme l'utilisation d'apprentissage supervisé avec des phrases générées par un modèle de langue, permettant d'améliorer les performances de modèles d'étiquetage grâce à la génération de données annotées