Construction de mosaïques de super-résolution à partir de la vidéo de basse résolution. Application au résumé vidéo et la dissimulation d'erreurs de transmission.

La numérisation des vidéos existantes ainsi que le développement explosif des services multimédia par des réseaux comme la diffusion de la télévision numérique ou les communications mobiles ont produit une énorme quantité de vidéos compressées. Ceci nécessite des outils d’indexation et de navigation efficaces, mais une indexation avant l’encodage n’est pas habituelle. L’approche courante est le décodage complet des ces vidéos pour ensuite créer des indexes. Ceci est très coûteux et par conséquent non réalisable en temps réel. De plus, des informations importantes comme le mouvement, perdus lors du décodage, sont reestimées bien que déjà présentes dans le flux comprimé. Notre but dans cette thèse est donc la réutilisation des données déjà présents dans le flux comprimé MPEG pour l’indexation et la navigation rapide. Plus précisément, nous extrayons des coefficients DC et des vecteurs de mouvement. Dans le cadre de cette thèse, nous nous sommes en particulier intéressés à la construction de mosaïques à partir des images DC extraites des images I. Une mosaïque est construite par recalage et fusion de toutes les images d’une séquence vidéo dans un seul système de coordonnées. Ce dernier est en général aligné avec une des images de la séquence : l’image de référence. Il en résulte une seule image qui donne une vue globale de la séquence. Ainsi, nous proposons dans cette thèse un système complet pour la construction des mosaïques à partir du flux MPEG-1/2 qui tient compte de différentes problèmes apparaissant dans des séquences vidéo réeles, comme par exemple des objets en mouvment ou des changements d’éclairage. Une tâche essentielle pour la construction d’une mosaïque est l’estimation de mouvement entre chaque image de la séquence et l’image de référence. Notre méthode se base sur une estimation robuste du mouvement global de la caméra à partir des vecteurs de mouvement des images P. Cependant, le mouvement global de la caméra estimé pour une image P peut être incorrect car il dépend fortement de la précision des vecteurs encodés. Nous détectons les images P concernées en tenant compte des coefficients DC de l’erreur encodée associée et proposons deux méthodes pour corriger ces mouvements. Unemosaïque construite à partir des images DC a une résolution très faible et souffre des effets d’aliasing dus à la nature des images DC. Afin d’augmenter sa résolution et d’améliorer sa qualité visuelle, nous appliquons une méthode de super-résolution basée sur des rétro-projections itératives. Les méthodes de super-résolution sont également basées sur le recalage et la fusion des images d’une séquence vidéo, mais sont accompagnées d’une restauration d’image. Dans ce cadre, nous avons développé une nouvelleméthode d’estimation de flou dû au mouvement de la caméra ainsi qu’une méthode correspondante de restauration spectrale. La restauration spectrale permet de traiter le flou globalement, mais, dans le cas des obvi jets ayant un mouvement indépendant du mouvement de la caméra, des flous locaux apparaissent. C’est pourquoi, nous proposons un nouvel algorithme de super-résolution dérivé de la restauration spatiale itérative de Van Cittert et Jansson permettant de restaurer des flous locaux. En nous basant sur une segmentation d’objets en mouvement, nous restaurons séparément lamosaïque d’arrière-plan et les objets de l’avant-plan. Nous avons adapté notre méthode d’estimation de flou en conséquence. Dans une premier temps, nous avons appliqué notre méthode à la construction de résumé vidéo avec pour l’objectif la navigation rapide par mosaïques dans la vidéo compressée. Puis, nous établissions comment la réutilisation des résultats intermédiaires sert à d’autres tâches d’indexation, notamment à la détection de changement de plan pour les images I et à la caractérisation dumouvement de la caméra. Enfin, nous avons exploré le domaine de la récupération des erreurs de transmission. Notre approche consiste en construire une mosaïque lors du décodage d’un plan ; en cas de perte de données, l’information manquante peut être dissimulée grace à cette mosaïque

Therapeutic Validity and Effectiveness of Preoperative Exercise on Functional Recovery after Joint Replacement: A Systematic Review and Meta-Analysis

Background: Our aim was to develop a rating scale to assess the therapeutic validity of therapeutic exercise programmes. By use of this rating scale we investigated the therapeutic validity of therapeutic exercise in patients awaiting primary total joint replacement (TJR). Finally, we studied the association between therapeutic validity of preoperative therapeutic exercise and its effectiveness in terms of postoperative functional recovery. Methods: (Quasi) randomised clinical trials on preoperative therapeutic exercise in adults awaiting TJR on postoperative recovery of functioning within three months after surgery were identified through database and reference screening. Two reviewers extracted data and assessed the risk of bias and therapeutic validity. Therapeutic validity of the interventions was assessed with a nine-itemed, expert-based rating scale (scores range from 0 to 9; score ≥6 reflecting therapeutic validity), developed in a four-round Delphi study. Effects were pooled using a random-effects model and meta-regression was used to study the influence of therapeutic validity. Results: Of the 7,492 articles retrieved, 12 studies (737 patients) were included. None of the included studies demonstrated therapeutic validity and two demonstrated low risk of bias. Therapeutic exercise was not associated with 1) observed functional recovery during the hospital stay (Standardised Mean Difference [SMD]: −1.19; 95%-confidence interval [CI], −2.46 to 0.08); 2) observed recovery within three months of surgery (SMD: −0.15; 95%-CI, −0.42 to 0.12); and 3) self-reported recovery within three months of surgery (SMD −0.07; 95%-CI, −0.35 to 0.21) compared with control participants. Meta-regression showed no statistically significant relationship between therapeutic validity and pooled-effects. Conclusion: Preoperative therapeutic exercise for TJR did not demonstrate beneficial effects on postoperative functional recovery. However, poor therapeutic validity of the therapeutic exercise programmes may have hampered potentially beneficial effects, since none of the studies met the predetermined quality criteria. Future review studies on therapeutic exercise should address therapeutic validity. (aut.ref.

Global assessment of marine plastic exposure risk for oceanic birds

Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species

Global assessment of marine plastic exposure risk for oceanic birds

Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species

Global assessment of marine plastic exposure risk for oceanic birds

Plastic pollution is distributed patchily around the world's oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.B.L.C., C.H., and A.M. were funded by the Cambridge Conservation Initiative’s Collaborative Fund sponsored by the Prince Albert II of Monaco Foundation. E.J.P. was supported by the Natural Environment Research Council C-CLEAR doctoral training programme (Grant no. NE/S007164/1). We are grateful to all those who assisted with the collection and curation of tracking data. Further details are provided in the Supplementary Acknowledgements. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Peer reviewe

Iron dynamics in the rhizosphere as a case study for analyzing interactions between soils, plants and microbes

Iron is an essential element for plants and microbes. However, in most cultivated soils, the concentration of iron available for these living organisms is very low because its solubility is controlled by stable hydroxides, oxyhydroxides and oxides. In the rhizosphere, there is a high demand of iron because of the iron uptake by plants, and microorganisms which density and activity are promoted by the release of root exudates. Plants and microbes have evolved active strategies of iron uptake. Iron incorporation by these organisms lead to complex interactions ranging from competition to mutualism. These complex interactions are under the control of physico-chemical properties of the soils in which they occur, and reciprocally iron uptake strategies of plants and microbes impact these soil properties. These iron-mediated interactions between soils, plants and microbes impact the plant growth and health and their analysis, together with that of the resulting iron dynamics, is of a major agronomic interest. Analysis of the complex interactions soils, plants and microbes represent also a unique opportunity to progress in our knowledge of the rhizosphere ecology. This progression requires merging complementary expertises and study strategies in soil science, plant biology and microbiology. This review provides information on (i) iron status in soil and rhizosphere, iron uptake by plants and microbes, and on (ii) the corresponding study strategies. Finally, illustrations of how integration of these approaches allows gaining knowledge in the complex interactions occurring in the rhizosphere are given

Iron dynamics in the rhizosphere as a case study for analyzing interactions between soils, plants and microbes

International audienceIron is an essential element for plants and microbes. However, in most cultivated soils, the concentration of iron available for these living organisms is very low because its solubility is controlled by stable hydroxides, oxyhydroxides and oxides. In the rhizosphere, there is a high demand of iron because of the iron uptake by plants, and microorganisms which density and activity are promoted by the release of root exudates. Plants and microbes have evolved active strategies of iron uptake. Iron incorporation by these organisms lead to complex interactions ranging from competition to mutualism. These complex interactions are under the control of physico-chemical properties of the soils in which they occur, and reciprocally iron uptake strategies of plants and microbes impact these soil properties. These iron-mediated interactions between soils, plants and microbes impact the plant growth and health and their analysis, together with that of the resulting iron dynamics, is of a major agronomic interest. Analysis of the complex interactions soils, plants and microbes represent also a unique opportunity to progress in our knowledge of the rhizosphere ecology. This progression requires merging complementary expertises and study strategies in soil science, plant biology and microbiology. This review provides information on (i) iron status in soil and rhizosphere, iron uptake by plants and microbes, and on (ii) the corresponding study strategies. Finally, illustrations of how integration of these approaches allows gaining knowledge in the complex interactions occurring in the rhizosphere are given

Poisonings with Suicidal Intent Aged 0-21 Years Reported to Poison Centers 2003-12

Introduction: Few studies explore the clinical features of youth suicide by poisoning. The use of both social and clinical features of self-poisoning with suicidal intent could be helpful in enhancing existing and creating new prevention strategies. We sought to characterize self-poisonings with suicide intent in ages 0 to 21 years reported to three regional poison control centers from 2003-2012.Methods: This study was a blinded retrospective review of intentional self-poisonings by those age 21 or younger captured by the Poison Information Control Network. Age, sex, substance(s) used, medical outcome, management site, clinical effects, and therapies were described using counts and percentages and analyzed using chi-square tests. We analyzed the medical outcome ranging from no effect to death using the Wilcoxon rank-sum test. Serious medical outcome was defined as death or major outcome.Results: We analyzed a total of 29,737 cases. The majority were females (20,945;70.5%), of whom 274 (1.3%) were pregnant. Most cases were 15-18 year olds (15,520;52.2%). Many experienced no effects (9,068;30.5%) or minor medical outcomes (8,612;29%). Males had more serious medical outcomes (p<0.0001), but females were more likely to be admitted to a critical care unit (p<0.0001). There were 17 deaths (0.06%), most in males (10; p=0.008). Of the 52 substances reported in the death cases, 12 (23.1%) were analgesics. In eight (47.1%) of the deaths, over two substances were used. Overall, drowsiness/lethargy (7,097;19.3%) and single-dose charcoal (8,815;16.3%) were frequently reported. Nearly 20% were admitted to critical care units (5,727;19.3%) and 28.7% went to psychiatric facilities (8,523). Of those admitted to hospitals (8,203), nearly 70% (5,727) required critical care units. Almost half <10 years old were evaluated and released (43;47.2%). Of the 114 reported substances for this population, 22.8% involved psychotropic medications, 15.8% analgesics, and 14% Attention Deficit-Hyperactive Disorder (ADHD) medications. Analgesics (13,539;33.6%) were the most common medication category used by all age groups. Typically only one substance (20,549;69.1%) was used.Conclusion: Undiagnosed ADHD may be a potential underlying cause for self-harming behaviors in the very young. Gender-specific suicide prevention strategies may be more effective at identifying those at risk than traditional measures alone. Further study into admitting practices by emergency physicians is needed to understand the difference in critical care admission rates based on gender. Once identified to be at-risk for suicidal behavior, access to analgesics and psychotropics should be monitored by care-givers especially in those between the ages of 15-18. [West J Emerg Med.–0