Historical Change of Seagrasses in the Mississippi and Chandeleur Sounds

Seagrasses are important coastal resources facing numerous stressors, and losses have been documented from local to global assessments. Under the broad theme of habitat loss and fragmentation, a study of historical change in total area and landscape configuration of seagrasses in the Mississippi and Chandeleur Sounds was conducted. Mapping data was collated from a multitude of previous projects from 1940 to 2011. Comparisons of seagrass area among various studies that used different mapping methods can result in overestimation of area change and misleading conclusions of change over time. The vegetated seagrass area (VSA) data were generalized to a common resolution for further analysis. Spatial configuration of the seagrass landscape was examined through: (1) an exploratory spatial data analysis using seagrass patch size distribution and hot spot analysis, and (2) a core set of seagrass landscape FRAGSTATS metrics and a principal component analysis to identify major pattern. This study demonstrated a comprehensive analysis across spatial and temporal scales and used multiple landscape indices (from habitat, species composition, VSA, patch size distribution, to spatial configuration at patch- and landscape-levels) to provide insights on the pattern and dynamics of the seagrass landscape. A conceptual model of seagrass landscape change based on two principal factors, overall landscape lushness and continuity, was proposed for the Mississippi Sound. Overall the study area lost seagrasses with contracted spatial extent over the 71-year period, ostensibly due to loss or reduction of protective island barriers and reductions in water quality. The seagrass landscape in the Mississippi Sound exhibited signs of area loss and fragmentation as far back as the 1940-1950s. The landscape in the 1970s was characterized by loss of habitat, loss of seagrass species, the lowest VSA, a faster rate of decline and a higher loss in VSA than before 1970, a low proportion of large-sized patches and their low contribution to VSA, a reduced intensity of hot spots, and a high degree of fragmentation. Recovery of seagrass occurred during the 1980s and 1990s, with the landscape exhibiting characteristics of a more contiguous and more vegetated condition throughout the early 2000s

Effects of Changes in Public Policy on Efficiency and Productivity of General Hospitals in Vietnam

The health sector reform programme which began in Vietnam in 1989 in order to improve the efficiency of the health system has altered the way in which Vietnamese hospitals operate. The programme put the spotlight on input savings. This study aims to examine the relative efficiency of hospitals during the health reform process and assess - by looking at the relative efficiency of hospitals - the effects of the regulatory changes. The study employs the DEA two-stage approach referring to data from 101 general public hospitals over the period 1998-2006. The study revealed that there was evidence of improvement in the productivity of Vietnamese hospitals over the period 1998-2006, with a progress in total factor productivity of 1.4% per year. Furthermore, the differences in hospital efficiency can be attributed to both the regulatory changes and hospital-specific characteristics. The user fees and autonomy measures were found to increase technical efficiency. Provincial hospitals were revealed to be more technically efficient than their central counterparts and hospitals located in the North East, South East and Mekong River Delta regions performed better that hospitals from other regions

Organizational socialization process in small companies in Finland – A study from newcomer’s perspective

According to Batistič and Kaše (2015), organizational socialization has been paid more attention in business research and gradually proven to be the important topic for practitioners. Research around this organizational socialization process is constantly conducted from different angles. However, the research about it in small companies is still limited. There are several studies about this topic in Finland but only on a single case and from a company's perspectives. Therefore, this thesis focused on the organizational socialization process in small companies in Finland through one of their newcomers’ perspectives, to figure out successful and novel practices. The research was conducted by semi-structured interviews with nine participants from nine small companies in Finland. They joined their companies fewer than six months prior to the time of interview. The interviews focused on (1) what has been included in their organizational socialization process (or ‘onboarding’ according to participants), (2) what their companies did to support the process, (3) what they did to facilitate it, and (4) what could have been done differently. The grounded theory research was used to find successful and novel tactics used by companies and newcomers through newcomers’ stories. Patterns and variations were identified through the coding exercise based on themes, grouping, and sorting. Findings from the interview data were categorized into two main groups: newcomer’s tactics and company’s tactics under newcomer’s perspectives. The newcomer’s tactics include ‘expectation setting’, ‘adaptation’, ‘work ownership’, and ‘relationship building’. The company’s tactics under newcomer’s perspectives include ‘provide basic info’, ‘quick hands-on work’, ‘trust and autonomy’, and ‘emotional support and networking’. About newcomer’s development areas, the participants thought that they could have ‘organized their time or schedule better’, ‘made their responsibilities clearer to others’, and ‘asked more’. They also thought that their companies could have organized the process better: ‘have a simple process and structure for onboarding’, ‘provide an introduction about company’s product(s)’, have proper documentation’, ‘communicate the expectation in detailed level and make it as clear and early as possible’, and have frequent check-in and feedback sessions’. Through the data analysis, most of the tactics were mentioned in previous research. Nonetheless, there are interesting ones that were considered important by newcomers, namely ‘expectation setting’, ‘giving trust and autonomy’ and ‘quick hands-on work’. There are also tactics that were more likely used by the more experienced newcomers than the less experienced ones, and vice versa. A design of organizational socialization process was proposed based on the inputs from participants and previous research. It should have a simple structure of process, proper introduction about company and product(s), good documentation, expectation setting, quick hands-on work, trust and autonomy, clear and frequent communication, feedback and performance discussion

Contribution à l’étude de nouveaux convertisseurs sécurisés à tolérance de panne pour systèmes critiques à haute performance. Application à un PFC Double- Boost 5 Niveaux

Les conditionneurs alternatifs – continu à absorption sinusoïdale (PFC) pour les applications critiques se distinguent par un haut niveau de performances tel que les THD réduits, un haut rendement et une bonne fiabilité. Leur importance est d’autant plus nécessaire qu’une continuité de service des alimentations est requise même en présence d’une défaillance interne de composant. Deux types de structures associées à leur commande sont réalisés à cet effet, les structures à redondance parallèle et les structure à redondance en série. Elles consistent respectivement en l’ajout d’un bras d’interrupteur dans le cas de la redondance parallèle, qui est une option plus compliquée et en une suppression d’une cellule de commutation dans le deuxième cas. L’étude présentée ici, consiste en premier lieu en une exploration et une évaluation de nouvelles familles de topologies multi-niveaux, caractérisée par un partitionnement cellulaire en série. Ces nouvelles topologies, ainsi que leurs variantes, comportent au moins une redondance structurelle avec des cellules mono-transistor à défaut de commande non critique et symétriques à point-milieu. Elles sont donc génériques pour la mise en parallèle et l’extension en triphasé. Cependant, elles sont pour la plupart peu compétitives à cause des composants qui sont souvent surdimensionnés et donc plus onéreuses, en comparaison avec la structure PFC Double-Boost 5 Niveaux à composants standards 600 V (brevetée par l’INPT – LAPLACE –CNRS en 2008) que nous étudions. Cette dernière constitue le meilleur compromis entre un bon rendement et une maîtrise des contraintes en mode dégradé. Sur le plan théorique nous montrons que le seul calcul de fiabilité basé uniquement sur un critère de premier défaut est inadapté pour décrire ce type de topologie. La prise en compte de la tolérance de panne est nécessaire et permet d'évaluer la fiabilité globale sur une panne effective (i.e. au second défaut). L'adaptation de modèles théoriques de fiabilité à taux de défaillance constant mais prenant en compte, au niveau de leurs paramètres, le report de contrainte en tension et l'augmentation de température qui résulte d'un premier défaut, permet de chiffrer en valeur relative, le gain obtenu sur un temps court. Ce résultat est compatible avec les systèmes embarqués et la maintenance conditionnelle. Un prototype monophasé de PFC double-boost 5 niveaux à commande entièrement numérique et à MLI optimisée reconfigurable en temps réelle a été réalisé afin de valider l’étude. Il permet une adaptation automatique de la topologie de 5 à 4 puis 3 niveaux par exemple. Ce prototype a également servi de test d'endurance aux transistors CoolMos et diodes SiC volontairement détruits dans des conditions d'énergie maîtrisée et reproductibles. D’autres campagnes d'endurance en modes dégradés ont été réalisées en laboratoire sur plusieurs centaines d’heures en utilisant ce même prototype. Nous nous sommes axés sur la détection de défauts internes et le diagnostic (localisation) rapide, d'une part par la surveillance directe et le seuillage des tensions internes (tensions flottantes) et d'autre part, par la détection d’harmoniques (amplitude et phase) en temps réel. Ces deux techniques ont été intégrées numériquement et évaluées sur le prototype, en particulier la seconde qui ne requiert qu'un seul capteur. Enfin, nous proposons une nouvelle variante PFC expérimentée en fin de mémoire, utilisant deux fois moins de transistors et de drivers pour les mêmes performances fréquentielles au prix d'un rendement et d'une répartition des pertes légèrement moins favorable que la structure brevetée. ABSTRACT : This work is an exploration and an evaluation of new variants of multi-level AC/DC topologies (PFC) considering their global reliability and availability: electrical safety with an internal failure and post-failure operation. They are based on a non-differential AC and centre tap connection that led to symmetrical arrangement cells in series. These topologies permit an intrinsic active redundancy between cells in a same group and a segregation capability between the two symmetrical groups of cells. More again, they are modular and they can be paralleled and derived to any number of levels. Only single low-voltage (600V) transistor pear cell is used avoiding the short-circuit risk due to an unwanted control signal. Comparisons, taking into account losses, distribution losses, rating and stresses (overvoltage and over-temperature) during the post-operation are presented. Results highlight the proposed 5-level Double-Boost Flying Capacitor topology. This one was patented at the beginning of thesis, as a solution with the best compromise. On the theoretical side, we show that the reliability calculation based only on a "first fault occurrence" criterion is inadequate to really describe this type of topology. The inclusion of fault tolerance capability is needed to evaluate the overall reliability law (i.e. including a second failure). The adaptation of theoretical models with constant failure rate including overvoltage and over-temperature dependencies exhibit an increasing of the reliability over a short time. This property is an advantage for embedded systems with monitoring condition. Local detection and rapid diagnosis of an internal failure were also examined in this work. Two methods are proposed firstly, by a direct flying caps monitoring and secondly, by a realtime and digital synchronous demodulation of the input sampled voltage at the switching frequency (magnitude and phase). Both techniques have been integrated on FPGA and DSP frame and evaluated on a AC230V-7kW DC800V – 31kHz lab. set-up. We put forward the interest of the second method which only uses one input voltage sensor. Finally, we propose in this dissertation a new generic X-level PFC Vienna using, in 5-level version, half transistors and drivers for identical input frequency and levels. At the cost of a slight increase of losses and density losses, this topology appears very attractive for the future. A preliminary lab. set-up and test were also realized and presented at the end of the thesis

Plastification en injection des polymères fonctionnels et chargés

L objectif principal de la thèse est de modéliser et visualiser les phénomènes de plastification des polymères dans le procédé d injection-moulage. Dans les procédés de transformation des polymères par un système vis-fourreau (extrusion, injection), la plastification est l étape durant laquelle le polymère originellement à l état solide est graduellement fondu et homogénéisé par le chauffage externe et l action mécanique de la friction contre les parois de l outillage et du cisaillement. Cette étape est capitale dans la maîtrise technique et économique du procédé, en termes d homogénéité thermique, de mélange des charges et de temps de séjour du polymère. Nous envisageons de visualiser et modéliser l ensemble du processus de plastification dans les monovis d injection. Afin de comprendre et de mesurer cette étape, nous avons conçu, validé et réalisé un fourreau à fenêtres. Ce système se compose de trois fenêtres de visualisation, insérées dans un fourreau en acier usiné par électroérosion. Le comportement mécanique de cet assemblage a été analysé par simulation numérique, sous différentes sollicitations thermiques, pressions et contraintes. L hétérogénéité des matériaux de structure (acier verre) a fait apparaître des problèmes potentiels de fuites, de fragilité qui ont été pris en compte dans la conception. Ce fourreau à fenêtres nous permet de visualiser et de suivre à l'aide des caméras scientifiques, les différents états du polymère une fois introduit dans l ensemble vis-fourreau. Les résultats confirment les hypothèses théoriques de la plastification. Certains sont mis en évidence, comme l existence d un lit solide adossé à l arrière du filet de la vis, ainsi que son évolution par rapport à la vitesse de rotation de la vis, ou l apparition des films fondus entre le filet de la vis et le lit solide, et entre la paroi du fourreau et le lit solide. Certains sont par contre à vérifier par d autres expériences, comme par exemple : l apparition de la rupture du lit solide quelle que soit la vitesse de rotation de la vis, la valeur de la vitesse du lit solide par rapport à la vitesse de rotation de la vis. Nous souhaitons aussi, grâce à ce système "fourreau transparent", pouvoir étudier, modéliser et visualiser les aspects de dispersion et de mélange des charges (traceurs, pigments, mélange maître) au sein de la matrice polymère à l état solide ou fondu.The main objective of the thesis is modelling and visualization of the phenomena of polymer plastication in the injection-moulding process. In injection moulding or in extrusion, plastication is the step during which polymer pellets are melted by the means of mechanical dissipation provided by a rotating screw and by thermal conduction coming from a heated metallic barrel. This step is crucial for melt thermal homogeneity, charge dispersion and fibre length preservation. Although there have been a large number of theoretical and experimental studies of plastication during the past decades, mostly on extrusion and mostly using the screw extraction technique, extremely few of them have dealt with trying to visualise plastication, let alone measuring the plastication profile in real-time. As a matter of fact, designing such equipment is an arduous task. We designed an industry-sized metallic barrel, featuring 3 optical glass windows; each window possessing 3 plane faces itself to allow for visualisation and record by synchronised cameras and lightening by lasers. The mechanical behaviour of this assembly was analysed by numerical simulation under different thermal stresses, pressures and constraints. The heterogeneity of structural materials (steel - glass) showed potential leakage problems, or fragility problems, that have been taken into account in the design. We named it "transparent barrel" or "barrel with glass windows". This "transparent barrel" allows us to visualize and follow through scientific cameras, the different states of the polymer when introduced into the screw-barrel. The images recorded can be further analysed by digital image processing. Preliminary results confirm the plastication theory and show a compacted solid bed and a melt pool side by side. The total plastication length is a direct function of screw rotation frequency as it is obvious from results on the melt pool width, which increases when the screw rotation frequency decreases. However, some evidence of solid bed breakage has been recorded, whereby the solid bed does not diminish continuously along the screw but is fractured in the compression zone. Some others results need to be checked with others experiments. We also wish, through this system "transparent barrel", to study, modelling and visualize the aspects of dispersion and mixing charges (tracers, pigments, master batch) in the matrix polymer.VILLEURBANNE-DOC'INSA-Bib. elec. (692669901) / SudocSudocFranceF

The Impact of Coexisting Coeliac Disease on Type 1 Diabetes

Coeliac disease (CD) coexists with type 1 diabetes (T1D) substantially more than in the general population. This body of work examines the broad and pervasive relationship between CD on T1D, including the epidemiology, screening practices, microvascular complications, quality of life (QoL), nutrition, glycaemic variability, and bone health. In particular, the contribution of gluten free diet (GFD) adherence is explored. Study 1: The 20-year incidence of CD in 4,379 people with T1D aged 5 years. Study 2: We systematically reviewed the epidemiology of CD in 11,157 youth with T1D alone and 587 with coexisting CD; 55% of CD cases were diagnosed within 2 years of T1D and 79% within 5 years. We concluded that CD screening should be performed at T1D diagnosis and repeated within 5 years of T1D. Study 3: Comparing 129 youth with T1D and CD vs 2,510 with T1D alone, retinopathy, albumin excretion rate (AER) and neuropathy did not differ. HbA1c was lower in those with CD (8.3% vs 8.6%, p=0.04), however elevated AER was more prevalent in those who did not adhere to the GFD (40% vs 23%, p=0.04). Study 4: In a case control study of 35 youth with T1D and 35 with coexisting CD, and their carers, generic and diabetes-specific QoL did not differ. Youth using insulin pumps had similar generic and diabetes specific QoL to those using multiple daily injections. However, those who did not adhere to the GFD had lower diabetes specific QoL and lower general wellbeing, as did their carers. Study 5: In a case control study using continuous glucose monitoring, youth with T1D and CD had greater glycaemic variability, with a shorter time to peak blood glucose levels (BGL), higher peak, and higher postprandial BGLs than T1D alone, despite similar pre-meal BGLs. Both groups had inadequate calcium, folate and fibre, with excessive saturated fat and sodium intake. Study 6: In a case control study utilising dual energy x-ray absorptiometry and peripheral quantitative computational tomography, youth with coexisting T1D and CD had lower bone mineral content, abnormal trabecular and cortical bone development, and a lower bone turnover state with reduced muscle pull vs T1D alone. These studies further our understanding of the impact of coexisting CD in T1D. The findings inform screening and management of CD, and provide evidence in support of GFD adherence to optimise clinical, dietary, and psychosocial management

Contribution à l'étude de nouveaux convertisseurs sécurisés à tolérance de panne pour systèmes critiques à haute performance (Application à un PFC Double- Boost 5 Niveaux)

Les conditionneurs alternatifs continu à absorption sinusoïdale (PFC) pour les applications critiques se distinguent par un haut niveau de performances tel que les THD réduits, un haut rendement et une bonne fiabilité. Leur importance est d autant plus nécessaire qu une continuité de service des alimentations est requise même en présence d une défaillance interne de composant. Deux types de structures associées à leur commande sont réalisés à cet effet, les structures à redondance parallèle et les structure à redondance en série. Elles consistent respectivement en l ajout d un bras d interrupteur dans le cas de la redondance parallèle, qui est une option plus compliquée et en une suppression d une cellule de commutation dans le deuxième cas. L étude présentée ici, consiste en premier lieu en une exploration et une évaluation de nouvelles familles de topologies multi-niveaux, caractérisée par un partitionnement cellulaire en série. Ces nouvelles topologies, ainsi que leurs variantes, comportent au moins une redondance structurelle avec des cellules mono-transistor à défaut de commande non critique et symétriques à point-milieu. Elles sont donc génériques pour la mise en parallèle et l extension en triphasé. Cependant, elles sont pour la plupart peu compétitives à cause des composants qui sont souvent surdimensionnés et donc plus onéreuses, en comparaison avec la structure PFC Double-Boost 5 Niveaux à composants standards 600 V (brevetée par l INPT LAPLACE CNRS en 2008) que nous étudions. Cette dernière constitue le meilleur compromis entre un bon rendement et une maîtrise des contraintes en mode dégradé. Sur le plan théorique nous montrons que le seul calcul de fiabilité basé uniquement sur un critère de premier défaut est inadapté pour décrire ce type de topologie. La prise en compte de la tolérance de panne est nécessaire et permet d'évaluer la fiabilité globale sur une panne effective (i.e. au second défaut). L'adaptation de modèles théoriques de fiabilité à taux de défaillance constant mais prenant en compte, au niveau de leurs paramètres, le report de contrainte en tension et l'augmentation de température qui résulte d'un premier défaut, permet de chiffrer en valeur relative, le gain obtenu sur un temps court. Ce résultat est compatible avec les systèmes embarqués et la maintenance conditionnelle. Un prototype monophasé de PFC double-boost 5 niveaux à commande entièrement numérique et à MLI optimisée reconfigurable en temps réelle a été réalisé afin de valider l étude. Il permet une adaptation automatique de la topologie de 5 à 4 puis 3 niveaux par exemple. Ce prototype a également servi de test d'endurance aux transistors CoolMos et diodes SiC volontairement détruits dans des conditions d'énergie maîtrisée et reproductibles. D autres campagnes d'endurance en modes dégradés ont été réalisées en laboratoire sur plusieurs centaines d heures en utilisant ce même prototype. Nous nous sommes axés sur la détection de défauts internes et le diagnostic (localisation) rapide, d'une part par la surveillance directe et le seuillage des tensions internes (tensions flottantes) et d'autre part, par la détection d harmoniques (amplitude et phase) en temps réel. Ces deux techniques ont été intégrées numériquement et évaluées sur le prototype, en particulier la seconde qui ne requiert qu'un seul capteur. Enfin, nous proposons une nouvelle variante PFC expérimentée en fin de mémoire, utilisant deux fois moins de transistors et de drivers pour les mêmes performances fréquentielles au prix d'un rendement et d'une répartition des pertes légèrement moins favorable que la structure brevetée.This work is an exploration and an evaluation of new variants of multi-level AC/DC topologies (PFC) considering their global reliability and availability: electrical safety with an internal failure and post-failure operation. They are based on a non-differential AC and centre tap connection that led to symmetrical arrangement cells in series. These topologies permit an intrinsic active redundancy between cells in a same group and a segregation capability between the two symmetrical groups of cells. More again, they are modular and they can be paralleled and derived to any number of levels. Only single low-voltage (600V) transistor pear cell is used avoiding the short-circuit risk due to an unwanted control signal. Comparisons, taking into account losses, distribution losses, rating and stresses (overvoltage and over-temperature) during the post-operation are presented. Results highlight the proposed 5-level Double-Boost Flying Capacitor topology. This one was patented at the beginning of thesis, as a solution with the best compromise. On the theoretical side, we show that the reliability calculation based only on a "first fault occurrence" criterion is inadequate to really describe this type of topology. The inclusion of fault tolerance capability is needed to evaluate the overall reliability law (i.e. including a second failure). The adaptation of theoretical models with constant failure rate including overvoltage and over-temperature dependencies exhibit an increasing of the reliability over a short time. This property is an advantage for embedded systems with monitoring condition. Local detection and rapid diagnosis of an internal failure were also examined in this work. Two methods are proposed firstly, by a direct flying caps monitoring and secondly, by a realtime and digital synchronous demodulation of the input sampled voltage at the switching frequency (magnitude and phase). Both techniques have been integrated on FPGA and DSP frame and evaluated on a AC230V-7kW DC800V 31kHz lab. set-up. We put forward the interest of the second method which only uses one input voltage sensor. Finally, we propose in this dissertation a new generic X-level PFC Vienna using, in 5-level version, half transistors and drivers for identical input frequency and levels. At the cost of a slight increase of losses and density losses, this topology appears very attractive for the future. A preliminary lab. set-up and test were also realized and presented at the end of the thesis.TOULOUSE-INP (315552154) / SudocSudocFranceF

Online teaching during the COVID-19 pandemic: Vietnamese language teachers’ emotions, regulation strategies and institutional policy and management

Teaching is often described as one of the most emotion-laden professions. In times of the COVID-19 pandemic, the conversion to online teaching has triggered new emotional experiences of teachers that not many studies have taken into account. Studying emotion from a poststructuralist lens, this study examines the emotional experiences of 10 language teachers in a university in Vietnam and their responses to the new teaching platforms. Analysis of the in-depth semi-structured interviews shows that the pedagogically and technologically distinctive features of online teaching aroused unique challenges for and emotions of the teachers, both positive and negative. Also, the teachers reported a number of strategies to cope with the new situation which we term as in-the-moment and out-of-class emotion regulation. The study highlights the need for acknowledgment and support for teachers in terms of resources, policy and management of institutions in the “new normal situation,” while displaying teachers’ self-reliance and emotional self-regulation. The article calls for attention to teachers emotion as an integral dimension of the profession, regardless of the physical or virtual setting of the classroom

Vietnamese university teacher mothers’ juggling roles when teaching online

Since the onset of the COVID-19 pandemic, people’s lives have been affected on a global scale. In academia in particular, the focus has been on the challenges of academic mothers juggling their careers with raising children during social distancing time. The excessive demand of work changes such as the conversion to online teaching and family increasing attention has given rise to additional workload and negative emotional responses of university teacher mothers. Analysing in-depth interviews with nine Vietnamese university teacher mothers of young children, this article shows how they had to reorganise their work-life structure as a result of the global COVID-19 pandemic. The article features the challenges and struggles of teacher mothers as they had to teach from home and homeschool their children at the same time, while navigating the ‘new normal’ situation in a way that least possible affected their life and work organisation. The article also unveils the lack of support from family members and the workplaces of the university teacher mothers and questions the gendered burden and inequality entailed by the pandemic. The study highlights how resilient the university teacher mothers were with constant changes in their personal and professional lives due to the pandemic. We argue that the new situation provided a unique opportunity for university teacher mothers to re-imagine their teaching practices and maternity performances in an interlacing way that they might not hitherto have considered