Добірка наукової літератури з теми "Trajectoire de lanceur"

Résumé Sur la base d'une psychothérapie intensive qu'il a faite avec un adolescent, psychothérapie qui s'est poursuivie durant 15 mois, à raison de 2 à 3 séances par semaine, l'auteur essaie de différencier la problématique d'une crise de la pathologie en évolution en cours de consultation. En alternance avec le matériel clinique, l'auteur utilise diverses notions théoriques qui permettent de comprendre ce matériel.

BackgroundSystemic sclerosis (SSc) is an autoimmune disease that is characterized by systemic vasculopathy and fibrosis. Pulmonary hypertension (PH), defined as elevated pulmonary arterial pressure (PAP), is one of the leading causes of death of SSc1. In recent years, various therapies have been developed to target each of the pathogenesis of SSc – autoimmunity, vasculopathy, and fibrosis. Accordingly, treatment strategies based on risk stratification for PH progression are aspired; however, prediction of changes in PAP in diverse patients with SSc has not been established2.ObjectivesTo visualize the patterns of PAP elevation in SSc and to identify the clinical characteristics of each trajectory, by applying latent trajectory modeling for PAP measured repeatedly by echocardiography.MethodsThis was a multicenter, retrospective cohort study conducted at four referral hospitals in Kyoto, Japan. Patients with SSc who visited the study site between April 2008 and March 2021 and had at least three echocardiographic measurements of systolic pulmonary arterial pressure (sPAP) were included in this study. Follow-up concluded in March 2021. A group-based trajectory model3 was applied to the change in sPAP over time, and individual patients were classified into distinct subgroups that followed similar trajectories. The number and shape of the trajectories were estimated based on adequacy, goodness of fit, parsimony, and interpretability of the model. Clinical plausibility was assessed by comparing PH-free survival, i.e., time to either PH or death, for each trajectory. Multinomial logistic regression analysis was performed for baseline clinical characteristics associated with trajectory assignment.ResultsA total of 236 patients with a total of 1097 sPAP measurements were included. We identified five trajectories following the quadratic function as “rapid progression (n=9, 3.8%)”, “early elevation (n=30, 12.7%)”, “mid elevation (n=54, 22.9%)”, “late elevation (n=24, 10.2%)”, and “low stable (n=119, 50.4%)”. Each trajectory, in this order, showed earlier elevation of sPAP and shorter PH-free survival (Figure 1). In the multinomial logistic regression (with the “low stable” as reference), cardiac involvement was associated with the “rapid progression” (adjusted odds ratio [OR] 28.9, 95% confidence interval [CI] 3.21–259.5), diffuse cutaneous SSc was associated with the “early elevation” (OR 4.08, 95% CI 1.27–13.1), anti-centromere antibody positive was associated with the “mid elevation” (OR 4.50, 95% CI 1.11–18.2), and older age of onset was associated with the above three trajectories.ConclusionThe pattern of changes in pulmonary artery pressure over time in SSc can be classified into five distinct trajectories. Each trajectory differed in baseline clinical characteristics and outcomes.References[1]Pokeerbux MR, et al. Survival and prognosis factors in systemic sclerosis: data of a French multicenter cohort, systematic review, and meta-analysis of the literature. Arthritis Res Ther. 2019;21(1):86.[2]Denton CP, et al. Systemic sclerosis. Lancet. 2017;390(10103):1685-1699.[3]Nagin DS, et al. Group-based trajectory modeling in clinical research. Annu Rev Clin Psychol. 2010;6:109-38.Disclosure of InterestsNone declared

Alexis Danan (1890-1979) est l'une des grandes figures médiatiques de la campagne contre les « bagnes pour enfants » dans la France des années trente. Le reporter n’est pas le premier ni le seul à écrire sur le sujet. Le nom du journaliste est celui que la mémoire de la réforme des établissements de correction a le plus conservé. En pleine période de lutte antifasciste et sous le Front populaire, des hommes et des femmes se mobilisent ; ils interpellent le pouvoir pour dénoncer le scandale et demander des réformes. Après avoir été un homme d'enquête, le journaliste Alexis Danan dénonce et interpelle le pouvoir dans un journal, Paris-Soir, devenu le quotidien le plus lu des Français. En mai 1936, il utilise le média pour lancer la Fédération nationale des comités de vigilance et d’action pour la protection de l’enfance malheureuse. La trajectoire d’un individu – donc une biographie – est un repère pour interroger autrement les processus sociaux et culturels qui, en amont, modifient l’environnement des actions publiques en direction de l’enfance irrégulière. Le journaliste engagé a pu incarner un mode de légitimité bien particulier dans un monde, celui de la protection de l’enfance. Son exemple est à la fois exceptionnel car la norme se trouve ailleurs, et attendu, au regard d’une image, celle d’un « quatrième pouvoir » en démocratie.

BackgroundDuchenne muscular dystrophy (DMD) is an x-linked ultra-rare neuromuscular condition affecting 1 in 3600–6000 live male births.1 Individuals live with an exceptional illness trajectory of prolonged dwindling frailty and high symptom burden.2 While it is recognised that a co-ordinated multidisciplinary team approach may increase the survival of those with DMD and improve their quality of life (QoL)3 adults are receiving less comprehensive and co-ordinated care compared with those in the paediatric service.4AimTo investigate QoL in adults with DMD living in the West of Scotland (WoS).MethodsThe SEIQoL-DW tool was used to assess the five most important elements that contribute to an individual’s QoL – these were then used to guide qualitative interviews with six men in the WoS. A thematic analysis was undertaken.ResultsMen living with DMD in the WoS described living good lives but feel ‘forgotten’ due to perceived gaps in their care: poorly co-ordinated and infrequent health care; lack of multi-disciplinary team input and holistic care; and poor or no access to allied health care professionals for example physiotherapy and psychological support.ConclusionsExisting guidelines rarely seem materialise as person-centred care. There are numerous opportunities to introduce palliative care gently as part of the MDT early in the illness trajectory and continue in a dynamic manner as time elapses and when trigger points arise. Better co-ordinated multi-disciplinary care with the inclusion of a palliative care specialist may be a solution allowing for an early introduction to palliative care and proactive advance care planning.References. Bushby K, et al. Diagnosis and management of duchenne muscular dystrophy part 1: Diagnosis and pharmacological and psychosocial managment. Lancet Neurol2010;9:77–93.. Landfeldt E, et al. The burden of duchenne muscular dystrophy. Neurology2014;83:529–36.. Bushby K, et al. Diagnosis and management of duchenne muscular dystrophy part 2: Implementation of multidisciplinary care. Lancet Neurol2010;9:177–89.. Rodger S, et al. Adult care for duchenne muscular dystrophy in the UK. J Neuro2015;262:629–41.

ObjectiveTo document clinical trial data flow in global clinical trials published in major journals between 2013 and 2021 from Global South to Global North.DesignScoping analysisMethodsWe performed a search in Cochrane Central Register of Controlled Trials (CENTRAL) to retrieve randomised clinical trials published between 2013 and 2021 from The BMJ, BMJ Global Health, the Journal of the American Medical Association, the Lancet, Lancet Global Health and the New England Journal of Medicine. Studies were included if they involved recruitment and author affiliation across different country income groupings using World Bank definitions. The direction of data flow was extracted with a data collection tool using sites of trial recruitment as the starting point and the location of authors conducting statistical analysis as the ending point.ResultsOf 1993 records initially retrieved, 517 studies underwent abstract screening, 348 studies underwent full-text screening and 305 studies were included. Funders from high-income countries were the sole funders of the majority (82%) of clinical trials that recruited across income groupings. In 224 (73.4%) of all assessable studies, data flowed exclusively to authors affiliated with high-income countries or to a majority of authors affiliated with high-income countries for statistical analysis. Only six (3.2%) studies demonstrated data flow to lower middle-income countries and upper middle-income countries for analysis, with only one with data flow to a lower middle-income country.ConclusionsGlobal clinical trial data flow demonstrates a Global South to Global North trajectory. Policies should be re-examined to assess how data sharing across country income groupings can move towards a more equitable model.

The lance is a critical component of the bottom-blowing pool melting process, and its placement has an important impact on the pool?s gas-liquid two-phase flow. In this study, a mathematical model of the bottom-blowing process is established, and the flow pattern, trajectory, wake vortex, and velocity of bubbles under four lance spacings are simulated. Results show that there are three basic bubble flow patterns appear in the flow field: bubbles coalesce before leaving the nozzle (Pattern I), bubbles coalesce after leaving the nozzle (Pattern II), and no coalescence during the rise of bubbles (Pattern III). The bubble pattern varies from Pattern I to Pattern III with the increase in lance spacing. The intensity of the influence of the wake vortex on the bubbles decreases. The Q (The Q is the second Galilean invariant of the velocity gradient tensor ?v.) value of the wake vortex is small, but the vortex structural distribution is complex. Moreover, there is a large velocity difference between gas and liquid at the beginning of gas injection, but the velocity difference between them decreases after gas injection, so the average turbulent kinetic energy in the pool initially increases sharply, and then approaches dynamic equilibrium. The top and bottom velocities of the bubbles are consistent, and the velocity fluctuation is orderly. Moreover, the greater the lance spacing is, the greater the disturbance in the pool is. The mixing effect of D = 0.2 m is the best among the four spacings.

The demographics and communicative disorders which traverse aging, neurocognitive disorders and auditory problems are staggering. Lancet Public Health1 estimates 57 million people globally with dementia in 2019 and by 2050 there will be 153 million cases. People seek counsel from hearing care professionals (HCPs) because of complaints and observations such as they cannot understand speech-in-noise (SIN), and/or they are not sure what someone just said, and/or they cannot recall the details of a recent conversation. For many, the complaints and observations of hearing and listening disorders are the same as, and may overlap with complaints and observations of, mild cognitive impairment and other neurocognitive disorders. In this article we review the current knowledge related to cognition and audition; we explore the practical reasons for incorporating cognitive screening into otolaryngology clinics, with specific regard to patients with hearing and listening problems. We review and explore auditory and cognitive disorders and we specify that these are not silos. That is, they may (and often do) occur in-isolation or in-tandem. We will review multiple studies which demonstrate that for some people, some of the time, early detection of neurocognitive anomalies may help facilitate an improved cognitive trajectory via hearing aid amplification, cochlear implantation, and through attending to modifiable risk factors.

Tous les ans, nombre d’entreprises lancent leur enquête d’engagement et les communicateurs internes sont sommés d’interroger des salariés, confrontés à des questions de sens. Partant du propos qu’« il faut s’engager pour engager », selon les mots d’un praticien, quelle sorte de professionnel engagé est ce praticien ? Celui-ci ne peut-il exercer son métier sans un investissement personnel fort ? De quoi est alors fait cet engagement ? Dans quelle mesure cet engagement influence-t-il la façon d’exercer son métier ? Telle est l’intrigue proposée et trois éclairages nous seront utiles pour la résoudre: sur l’engagement, sur la posture du praticien dans l’organisation, sur la dynamique de sa trajectoire professionnelle. Nous verrons que, engager demande de s’expliquer, de dialoguer, voire de se disputer autour du travail et de son organisation. La dimension communicationnelle du travail apparaît ainsi comme une évidence. Every year, companies launch their commitment survey and internal communicators are asked, as a matter of priority, to interview employees, who are confronted with questions of meaning. Starting from the premise that, in the words of a practitioner, “one must commit oneself to engage others”, we explore the nature of this commitment. Can the practitioner exercise his job without strong personal investment? What is the basis for his commitment? How does this commitment influence the way he does his job? To answer these questions, we will seek to clarify the nature of the practitioner’s commitment, his role within the organization and the dynamics of his career path. We will see that, in order to engage others, internal communicators have to explain, to exchange ideas, to enter into a dialogue and even to argue about the work and its organization and the relations between individual employees. The communication dimension of his work thus seems obvious.

Background: Gastric cancer remains a global malignancy. The role of bibliometric analysis is increasingly valued. It is feasible and necessary to perform a bibliometric analysis to regurgitate studies in the prognosis of gastric cancer. Materials and methods: Web of Science was selected for the dataset resource. Articles published between 2000 and 2020 within the database of Web of Science Core Collection were included with predefined search terms. CiteSpace version 5.7.R1 and R software program version 4.0.3 were used for bibliometric analysis with parameters extrapolated from included studies. Results: A total of 1721 articles were included from 2000 to 2020 with remarkably increasing trends. China (n=1183), Japan (n=218), and South Korea (n=119) showed the most publications. SUN YAT SEN University, FUDAN University, and NANJING MED University were the top institutions with most publications. Keywords with strongest citation bursts between 2000 and 2020 were characterized. Particularly, “statistics”, “resistance”, “mortality”, “lncrna”, “diagnosis”, “outcome”, “migration”, “promote,” and “regulatory t cell” were the latest rising keywords since 2017, indicating possible study trends ahead. Several articles showed strongest citation bursts, including Jemal A. CA-CANCER J CLIN, Van Cutsem E. LANCET, and Japanese Gastric Cancer Association GASTRIC CANCER. Conclusion: This bibliometric analysis provides a thought-provoking, insightful result concerning the trajectory of research development in prognosis of gastric cancer with a future perspective.

Ce travail de thèse porte sur l’amélioration d’un logiciel interne à l’entreprise ArianeGroup dédié à l’optimisation des trajectoires des lanceurs. La version originale est capable de trouver une trajectoire à consommation minimale pour un étage supérieur d’un lanceur tri-étages depuis une position extérieure à l’atmosphère en un ou deux boosts par une méthode entièrement automatique. L’objectif est d’utiliser ce travail existant pour créer une méthode capable de trouver une trajectoire à consommation minimale pour un étage supérieur d’un lanceur en configuration bi-étages. Dans ce cas de figure, l’étage a une plus faible vitesse initiale, une masse initiale plus grande et il est allumé à une altitude plus faible. Les améliorations concernent également l’ajout d’une contrainte de flux thermique maximal, une contrainte de durée sur l’arc balistique et une contrainte de largage de la coiffe sur un critère de flux thermique. De plus, le nouveau logiciel est maintenant capable de cibler différentes combinaisons de paramètres orbitaux. On utilise le travail réalisé sur les configurations bi-étages pour ajouter une contrainte de largage d’étage et donc optimiser le transfert orbital d’un lanceur tri-étage depuis l’éjection des boosters grâce à cette méthode. Toutes ces améliorations sont basées sur des développements mathématiques nouveaux à propos des problèmes de contrôle optimal hybrides, en particulier quand la dynamique du problème est celle du vol d’un lanceur
This thesis work is about the improvement of an ArianeGroup in-house software dedicated to the optimization of launcher trajectories. The original version is able to find a minimum consumption trajectory for an upper stage of a three-stage launcher outside the atmosphere in one or two boosts through a fully automatic method. The goal is to build on this existing work to create a method capable of finding an upper stage trajectory for a two-stage launcher. The specificity is that the stage has a lower initial velocity, a heavier mass and it is ignited at a lower altitude. The improvements also concern the addition of a maximum thermal flux constraint, a ballistic duration constraint and a fairing jettisoning constraint on a thermal flux criterion. Moreover, the new software is now able to target different combinations of orbital parameters. We take advantage of the work done on two-stage launchers to make the software capable of jettisoning a lower stage and thus optimizing the transfer of a three-stage launcher since the ejection of boosters. All these improvements are based on subsequent mathematical developments and novelties about hybrid optimal control problems, in particular when the dynamics of the problem is that of the flight of a launcher

Ce travail porte sur deux problèmes d'optimisation de trajectoires spatiales: le vol d'un dernier étage de lanceur, et le nettoyage des débris spatiaux. L'objectif est de développer pour ces deux problèmes des méthodes de résolution et des logiciels utilisables dans un contexte industriel. Les travaux comportent une partie théorique de formulation et une partie appliquée de résolution numérique. Les domaines abordés sont la mécanique spatiale, l'optimisation discrète, l'optimisation continue en dimension finie et le contrôle optimal.

Le travail porte sur deux problèmes d’optimisation de trajectoires spatiales: le vol d’un dernier étage de lanceur, et le nettoyage des débris spatiaux. L'objectif est de développer pour ces deux problèmes des méthodes de résolution et des logiciels utilisables dans un contexte industriel. Vol d’un dernier étage de lanceur. Pour la résolution du vol d’un dernier étage de lanceur, deux approches différentes par continuation sont envisagées à partir de simplifications des modèles. La première approche consiste à résoudre le problème en Terre plate, avec un champ de gravité uniforme, puis à revenir au problème en Terre ronde par une double continuation sur la gravité et sur la courbure de la Terre. La deuxième approche consiste à résoudre le problème impulsionnel, correspondant à un niveau de poussée infini, puis à revenir au problème en poussée continue par une continuation sur le niveau de poussée. L'objectif est de définir un processus de résolution le plus automatique possible, applicable pour différent jeux de données du problème réel : caractéristiques du lanceur, orbite à atteindre. Nettoyage des débris spatiaux. La sélection des débris et de l'ordre de visite est un problème de type plus court chemin dans un graphe à coûts dépendant du temps. Une stratégie type permet de ramener le problème de contrôle optimal à un problème d’optimisation continue en dimension finie, dont la résolution peut être couplée au problème de chemin. Une linéarisation locale permet ensuite de mettre en œuvre des algorithmes de séparation-évaluation. En itérant le processus de linéarisation – résolution à partir d’une solution initiale, on pourra converger vers la solution du problème
The work addresses two space trajectories optimization problems : the flight of a launcher upper stage and the collecting of space debris. For these two problems the goal is to develop resolution methods and softwares usable in an industrial framework. Flight of a launcher upper stage. For the problem of a launcher upper stage flight, two continuation approaches are envisioned from models simplifications. The first approach consists in solving the flat Earth problem with uniform gravity, then to come back to the round Earth problem through a double continuation on the gravity and on the earth curvature. The second approach consists in solving the impulsive problem, corresponding to an infinite thrust level, then to come back to the continuous thrust problem through a continuation on the thrust level. The goal is to define a solving procedure as automatic as possible for various instances of the real problem : launcher configuration, targeted orbit. Space debris collecting. The selection of the debris and the visiting order is a shortest path problem in a time-dependent valuated graph. A generic strategy reduces the optimal control problem to a nonlinear programming problem of finite dimension, which can be coupled to the path problem. A local linearization around an initial solution allows to set up a Branch and Bound algorithm. The reference solution is then updated with the linearized solution. Iterating on the linearization-resolution process from the pre-optimized initialization allows converging to the solution of the global problem

Cette thèse traite de la trajectographie exo-atmosphérique d'un lanceur. Cette probl ématique repose sur la résolution d'un problème d'optimisation contraint : le problème aux deux bouts. Ce dernier consiste à trouver les actions à prendre afin d'atteindre la position et la vitesse désirées en consommant le moins d'énergie possible. Ces actions doivent respecter les contraintes imposées par la dynamique et la structure du véhicule. En plus, dans le cas d'un lanceur, le contrôle s'effectue uniquement en modifiant l'orientation de la poussée. Pour résoudre ce problème, le projet de doctorat est divisé en trois parties distinctes : la modélisation de la dynamique, l'obtention d'une trajectoire de référence et la fonction de guidage. La première partie, la modélisation, consiste à obtenir un modèle précis et réaliste de la dynamique de translation d'un lanceur. Elle passe donc par l'application de la seconde loi de Newton sur le centre de masse du lanceur. Dans cette thèse, ceci est effectué en utilisant trois représentations différentes, dont une nouvelle utilisant un quaternion qui permet de combler le vide entre les deux représentations existantes. À la suite de l'obtention d'un modèle du véhicule à guider, il devient possible de définir une trajectoire de référence régie par cette dynamique. Pour y parvenir, ce projet propose une optimisation directe où l'orientation de la poussée est discrétisée et correspond aux inconnues du problème d'optimisation. Le critère de ce problème d'optimisation inclut des termes utilisant des connaissances a priori de la trajectoire pour améliorer les propriétés de convergence. Le problème d'optimisation inclut également des contraintes, relaxées par des variables d'écart, sur l'orbite d'injection. La trajectoire résultante est utilisée comme consigne dans une fonction de guidage par suivi de trajectoire. Le suivi de trajectoire est une façon contournée de traiter le problème aux deux bouts et d'accélérer la résolution du problème de guidage afinn de s'insérer dans les capacités de calcul embarqué. Les algorithmes développés dans cette thèse sont basés sur la commande prédictive où les sorties du modèle prédictif sont les paramètres orbitaux instantanés de la trajectoire. Le premier algorithme utilise un modèle non-linéaire de prédiction alors que les deux autres sont basés sur une représentation linéaire variante dans le temps et sur une représentation linéaire fractionnelle. Ces trois algorithmes sont comparés à une solution classique en guidage de lanceur qui résout directement le problème aux deux bouts. Bien que les algorithmes développés produisent une orbite plus près de celle désirée et y parviennent en consommant moins de carburant, le temps de calcul nécessaire à leur résolution et leur piètre robustesse font en sorte qu'ils ne constitue pas une alternative intéressante à la solution de référence.
This thesis deals with the exo-atmospheric trajectory of a space launcher. The solution is obtained by solving a constrained optimization problem : the two-point boundary value problem. The solution is the required actions to reach the desired position and velocity while consuming the least energy as possible. These actions must comply with the constraints imposed by the dynamics and the structure of the vehicle. Also, for a space launcher, the control is limited to the thrust orientation. To solve this problem, this project is divided into three distinct parts : modeling the dynamics, obtaining a reference trajectory and the guidance function. The first part, the modeling, is the definition of an accurate and realistic model of the space launcher translational dynamics. Therefore, it requires the application of Newton's second law on the launcher center of mass. In this thesis, this is carried out using three different representations. The representation using a full quaternion is new to this field of application and fills the hole between the two others. With the model of the vehicle to be guided, it becomes possible to define a reference trajectory governed by this model. To do it, this project proposes a direct optimization where the thrust orientation is discretized and becomes the unknown of the optimization problem. The criterion of this optimization problem includes terms for a priori knowledge of the trajectory improving the convergence properties of the optimization. The optimization problem also includes constraints, relaxed by slack variables, on the injection orbit. The resulting trajectory is used as reference in a trajectory tracking guidance function. The trajectory tracking is a way to circumvent the resolution of the two-point boundary value problem, which accelerates the resolution to fit in on-board computing capabilities. The algorithms developed in this thesis are based on predictive control in which the outputs of predictive model are the instantaneous orbital parameters of the trajectory. A first algorithm uses a non-linear model for prediction while two others are rather based on a linear time-varying representation and a linear fractional representation. These three algorithms are compared to a conventional space launcher guidance solution, which directly solves the two-point boundary value problem. Even if the developped algorithms give a more accurate orbit and a less consuming trajectory, their computationnal time and poor robustness properties do not make them a viable alternative to the comparison solution.

We are developing a new technique, called nanoinjection, to insert foreign DNA into a living cell. Such DNA transfection is commonly used to create transgenic organisms vital to the study of genetics, immunology, and many other biological sciences. In nanoinjection, DNA, which has a net negative charge, is electrostatically attracted to a micromachined lance. The lance then pierces the cell membranes, and the voltage on the lance is reversed, repelling the DNA into the cell. This paper presents a mathematical model to predict the motion (trajectory) of DNA particles within a cell in the presence of the electric field developed by the lance and the substrate. The model is used to predict the scattering of DNA through the cell due to electrostatic repulsion. We are currently preparing experiments which will be used to validate the model.