Au Sénégal, la région de Kédougou située au sud-est du pays est considérée comme une zone sentinelle d’endémie pour les arbovirus. Le modèle en est représenté par le virus de la Fièvre jaune (VFJ) qui circule à bas bruit avec des amplifications périodiques tous les 4 à 6 ans. Cependant, peu de données sont à ce jour produites sur les déterminants de la dynamique d'émergence des arboviroses d’importance humaine dans la région. Ainsi, la région de Kédougou a été marquée depuis le début des années 2000 par un développement socio-économique et démographique remarquable qui compte parmi les facteurs anthropiques susceptibles de modifier la diffusion des arboviroses dans la région. Notre travail de recherche a évalué la dynamique des arboviroses émergentes et ré-émergentes dans l’écosystème de Kédougou. Pour ce faire, nous avons mis en place un système de surveillance multidisciplinaire (épidémiologique, entomologique et virologique), réalisé une étude de séroprévalence de l’infection par l’arbovirus Chikungunya (CHIKV) et produit une analyse par modélisations afin d’identifier les facteurs environnementaux et anthropiques liés à la dynamique des émergences arbovirales dans la région. Ce système de surveillance sentinelle a permis la détection d’amplifications du cycle selvatique du CHIKV et VFJ en 2009 et 2011, avec la circulation de ces deux virus chez l’homme (notamment 20 cas de Chikungunya en 2009 et 13 cas confirmés et 10 cas probables de fièvre jaune en 2011). L’adaptation au contexte domestique du moustique vecteur Aedes aegypti, l’urbanisation non contrôlée, la migration massive des populations ainsi que le mouvement des troupeaux de bétails ont été retrouvés comme facteurs pouvant contribuer à l’émergence et à la propagation des arbovirus au Sénégal et dans la région de Kédougou ainsi que dans le reste du Sénégal. Ce modèle d’observatoire multidisciplinaire associé aux outils de modélisation, au système d’information géographique et au développement de l’épidémiologie moléculaire et de la génomique devrait être étendu à d’autres pays de la région d’Afrique de l’Ouest pour renforcer la surveillance et anticiper l’émergence des épidémies en permettant la mise en place de stratégies de prévention et de contrôle pragmatiques et évolutives. / Located in southeastern Senegal, the Kedougou region is considered as an endemic zone for arboviruses with periodic amplifications every 4 to 6 years, as foreseen for the dynamic of the infection by the yellow fever virus (YFV). However, few data are available on the human specific circulation concern for arboviruses in humans in the region. In addition, the Kedougou region has been marked since the early 2000’s by a considerable socio-economic and demographic development that is to be addressed for changing the spreading of arboviruses with human concern in the area. Our research aimed to assess the dynamic of the circulation of emerging and re-emerging arboviruses in the ecosystem of Kedougou, southeastern Senegal, located close to the border of Mali and Guinea. Hence, we have set up a multidisciplinary (epidemiological, entomological and virological) sentinel surveillance system, carried out a CHIKV seroprevalence study and finally carried out modeling studies in to identify environmental determinants related to the emergence of arboviruses in the region. This system has detected an amplification of CHIKV and YFV sylvatic cycle respectively in 2009 and 2011 associated with a human circulation of these viruses with 20 identified cases of Chikungunya in 2009 and 13 confirmed and 10 probable cases of yellow fever in 2011. Concurrently, adaptation to the domestic context of the Aedes aegypti mosquito competent vector, uncontrolled urbanization, massive migration of populations as well as the movement of livestock have been found as potential factors contributing to the emergence and spreading of arboviruses. This multidisciplinary observatory model combined with mathematical modeling tools, geographic information system and the development of molecular epidemiology and genomics should be extended to other West African countries to strengthen the arboviruses surveillance and anticipate the emergence of epidemics through the implementation of prevention and effective control strategies.

Mississippi growers often have issues with corn seedling establishment due to saturated and cool soils, which can reduce productivity. Our first objective was to quantify yield reduction associated with variable emergence. Four patterns simulating various extent of affected plants and four different emergence delays were hand planted uniformly at a standard population. Plants were closely monitored to document emergence variability. Growth stages were measured three separate ways to identify the best field method to characterize stand variability. Data suggest there were yield disadvantages associated with emergence variability. Another objective was to evaluate practical replanting methods for Mid-South corn growers. Treatments included four populations planted at a normal time and replant interval. Two different series of treatments were imposed to evaluate the productivity of intra-planting seed in a partial stand. Corn grain yield was 11% greater when replanting in a clean seedbed, compared to all intra-planted treatments.

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Image processing systems have typically exhibited a high degree of application specificity. This makes it unlikely that any of the processing tasks for one application can be applied to another. Research has also found that such systems had not made use of knowledge about human perception although, it can be argued, such knowledge is independent of the application. This thesis takes the view that the structures which people perceive in pictures are of considerable importance to supporting picture-based human computer interaction. However, the design of systems which process pictures based on knowledge of human perception presents two major challenges. The first relates to determining the appropriate psychological knowledge that the computational modelling effort will be based upon. The second relates to the testing and evaluation of systems that aim to generate perceptually-valid structures, which poses significant problems because such systems are concerned with perceptual structures rather than semantic interpretations. An approach to developing picture processing systems is proposed that overcomes these problems. The approach represents a development strategy that exploits psychological theory in constructing image processing algorithms. The aim of these algorithms is to generate structures that match those perceived by humans. The approach enables new algorithms to be developed as additional psychological knowledge becomes available. Given appropriate training, users of such systems are able to see in images the structures that are generated by the system. The thesis presents the results of a study of perceptual and computational approaches to the processing of pictures. Motivations for and the development of a computational model based on perceptual grouping are described. A thorough evaluation of the computational model is performed which highlights both its value and limitations. Specific applications of the computational model in areas such as shape emergence in design, and pictorial databases, are then considered.

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Vegetable soybean, also known as edamame, has become increasingly popular in the United States due to its excellent nutrition and health benefits. This rising demand has sparked the interest of local farmers in growing edamame. However, a significant problem in edamame production is the poor seedling emergence. This dissertation focuses on three key objectives: 1) exploring the physiological traits linked to the low emergence of edamame seeds; 2) enhancing edamame seedling emergence by identifying genotypes with high vigor and resistance to soil-borne diseases; and 3) determining the optimal temperature for edamame seedling emergence. The study includes newly developed edamame breeding lines from the soybean breeding programs at Virginia Tech and the University of Arkansas, and major edamame cultivars commonly used in the Mid-Atlantic region. The results have identified several genotypes that exhibit high seeding vigor, aging tolerance, and consistently achieve a plant stand of over 80% in both laboratory and field conditions. It is also clarified that edamame's larger seed size leads to lower germination rates and slower emergence, although this is not correlated to total emergence. Moreover, environmental factors, pathogens and temperature, impact emergence. The study highlights that current edamame genotypes are commonly affected by soilborne pathogens, including Rhizoctonia solani, Athelia rolfsii, and Pythium irregulare, leading to seed rot and seedling damping off. However, the research has successfully identified partially resistant varieties characterized by significantly low disease indexes (p<0.05). Furthermore, the optimal temperature range for edamame seedling emergence (25-32°C) was found to be lower than that of other types of soybeans such as grain-type soybeans (29-36°C). This research provides a scientific foundation to improve edamame production practices. / Doctor of Philosophy / Vegetable soybean, also known as edamame, commonly consumed as a healthy snack, is steadily gaining popularity in the United States. However, there are significant challenges in achieving successful edamame plant growth from seeds. This research focuses on three primary objectives: first, understanding the underlying factors contributing to poor seedling emergence in edamame; second, identifying edamame genotypes with exceptional vigor and resistance to soil-borne diseases; and third, determining the ideal temperature conditions for optimal edamame seedling development. To accomplish these goals, a comprehensive study was conducted, encompassing various edamame varieties, including those developed by Virginia Tech and the University of Arkansas. The research identified some edamame genotypes that exhibited exceptional seed vigor, aging tolerance, and consistently achieved plant stands of over 80% under both laboratory and field conditions. Additionally, we also learned that bigger edamame seeds take longer time to grow, but the seed size does not affect the total emergence. Furthermore, we found that some diseases in the soil can hurt edamame seedlings, but we identified a few genotypes that are more resistant to these diseases. Lastly, in terms of temperature, we found that edamame seedlings grow the best between 25-32°C, which is slightly lower than other types of soybeans. Overall, this research helps farmers grow better edamame and brings more delicious and healthy food to our tables.

Enterprise Systems (ESs) are more than a collection of people, technology, processes, and capabilities. The responsibilities of post implementation management of ES lie in the unit called the Competency Center (CC). The CC has a bidirectional relationship with ESs wherein the CC influences the shaping of ESs, and the CC is affected by the dynamic interaction between people, technology, process, and capabilities within the ES. These dynamic interactions keep the CC, fluid and always in-process. The general-use definition of the term “process” as used in the Enterprise Systems literature treats the notion as “repeatable processes” or "replicable processes". However, arising from comparative case studies in four large organizations, I found that decision making, managing, and governing in the ES are not “replicable processes”, not reifications of structural variations over time when examined through the lens of the Assemblage Theory. Assemblage Theory incorporates the dynamic interplay of two continua: the first, territorialization, deterritorialization, and reterritorialization, and the second, material vs. expression. Although the notion of the terms formation, deformation, and reformation are suitable for understanding the processes these CCs encounter in a broad and general manner, they do not sufficiently describe the not-so-solid, never-quite-finished, always in-process or structuring referred to by Hopper (1996) as "emergent regularities". In contrast to the notion of stable structures, this dissertation research adopts the language of Deleuzian assemblage of Territorialization, deterritorialization, and Reterritorialization. Although the four study organizations planned and intended to develop clearly defined competency centers, which would create formalized processes and procedures to manage the post implementation phase, none of the study organizations ever achieved the anticipated stability. Instead, the CCs exhibited the signs of being ‘in-process’ and ‘structuring’. The contribution of this research to the IS field is an understanding of the CCs as processes as opposed to structures and how CCs structuring impact the ESs in organizations.

Human cytomegalovirus (HCMV) is a major cause of morbidity and mortality amongst immuno-compromised individuals and is the leading cause of congenital diseases amongst newborn infants. Mouse CMV (MCMV) infection of inbred mice has been extensively used as a model for HCMV pathogenesis and host-virus interaction. Macrophages are a key target cell type in the pathogenesis of human and mouse CMV infections. Macrophages are semi-permissive to CMV infection, however, the nature of this restrictive mechanism of infection is open for investigation. In this thesis, I hypothesized that macrophage permissivity is determined by the dynamic interplay of the innate response during the immediate-early (IE) period of infection. To test this hypothesis, I first developed and validated a flow cytometry based assay. In MCMV infected macrophages, I found heterogeneous expression from the major IE promoter (MIEP) leading to the development of a refractory subpopulation for IE expression. I further developed a computational modelling approach to help elucidate the dynamics of infection during this period. Modelling work revealed that the occurrence of refractory subpopulation could be caused by either 1) pre-existence of heterogeneous permissivity of macrophages prior to infection or 2) through an emergent process. Experimental testing of the models shows that the heterogeneous IE expression of homogeneously infected macrophages is caused by an emergent process. MCMV infection using type I interferon receptor and signal transducers and activator of transcription 1 (Stat1) knockout macrophages reveals that the emergence of refractory subpopulation is predominantly mediated by type I interferon through Stat1. Comparative molecular analysis between progressively infected and refractory subpopulations reveals that MCMV MIEP activation in the refractory subpopulation is stochastically inhibited by high expression of type I interferon induced antiviral components.

Thesis advisor: Mary Ann Glynn / My dissertation examines changes in audience sensemaking by the public and media about Apple’s novel product, iPad. My study begins on December 28, 2009, one-month before the introduction of the iPad by Apple and ends with the anniversary of its retail availability on April 2, 2011, shortly after the launch of the second-generation iPad. Using primarily qualitative methods, I analyze archival data including online forums and news articles to understand audience sensemaking as it unfolds. I investigate how sensemaking by the two audiences a) changes over time, b) changes with different types of material interaction with the product, c) incorporates the use of functional and symbolic frames in their public discourse about the iPad, and d) changes based on the public role of the audience. In doing so, I advance explanations as to how meanings about novel products stabilize. More broadly, I elaborate how nascent product categories can emerge by focusing on the cultural-cognitive processes that undergird product classification systems. As a result, I offer novel pathways for product category emergence. / Thesis (PhD) — Boston College, 2016. / Submitted to: Boston College. Carroll School of Management. / Discipline: Management and Organization.