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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Coupling of ecological and water quality models for improved water resource and fish management

Tillman, Dorothy Hamlin 15 May 2009 (has links)
In recent years new ideas for nutrient management to control eutrophication in estuarine environments have been under consideration. One popular approach being considered in the Chesapeake Bay Program is called the “top down” approach based on the premise that restoring algal predators, such as oysters and menhaden, will limit excess phytoplankton production and possibly eliminate costly nutrient control programs. The approach is being considered to replace or use in conjunction with the “bottom up” approach of reducing nutrient loads. The ability to model higher trophic levels such as fish, as well as the eutrophication processes driving production of primary producers in an aquatic ecosystem is needed. CE-QUAL-ICM (ICM) and Ecopath were two models selected for this research. ICM is a time- and spatial-varying eutrophication model that uses nutrient loads to predict primary producers, while Ecopath is a static mass balance model representing an average time period (e.g., season or year) and uses values of primary producers and other groups to predict fish biomass. Linking the two models will provide the means of going up the food chain by trophic levels. The Chesapeake Bay was chosen as the study site since both models are in use there. Before coupling ICM and Ecopath, common links between the two models were found. Ten groups were identified with such variables as production rates, consumption rates, and unassimilated food/consumption. A post-processor/subroutine was developed for ICM to aggregate output data from 3-D to 0-D to be used in Ecopath. Two Ecopath runs were developed with data from ICM and the Chesapeake Bay (CB) Ecopath model to see how network interactions differed with data representing the same system. Four additional runs were made, creating perturbations (i.e., increased phytoplankton production) using the CB Ecopath model and replacing the primary producers with data from ICM. Final runs of ICM were conducted looking at adjusting three parameters to try to restore the Bay back to 1950 conditions. It was demonstrated that ICM data can be coupled with Ecopath to study management strategies in eutrophication. Because of model formulations there was no data exchange from Ecopath back to ICM.
2

Applying Natural Language Processing and Deep Learning Techniques for Raga Recognition in Indian Classical Music

Peri, Deepthi 27 August 2020 (has links)
In Indian Classical Music (ICM), the Raga is a musical piece's melodic framework. It encompasses the characteristics of a scale, a mode, and a tune, with none of them fully describing it, rendering the Raga a unique concept in ICM. The Raga provides musicians with a melodic fabric, within which all compositions and improvisations must take place. Identifying and categorizing the Raga is challenging due to its dynamism and complex structure as well as the polyphonic nature of ICM. Hence, Raga recognition—identify the constituent Raga in an audio file—has become an important problem in music informatics with several known prior approaches. Advancing the state of the art in Raga recognition paves the way to improving other Music Information Retrieval tasks in ICM, including transcribing notes automatically, recommending music, and organizing large databases. This thesis presents a novel melodic pattern-based approach to recognizing Ragas by representing this task as a document classification problem, solved by applying a deep learning technique. A digital audio excerpt is hierarchically processed and split into subsequences and gamaka sequences to mimic a textual document structure, so our model can learn the resulting tonal and temporal sequence patterns using a Recurrent Neural Network. Although training and testing on these smaller sequences, we predict the Raga for the entire audio excerpt, with the accuracy of 90.3% for the Carnatic Music Dataset and 95.6% for the Hindustani Music Dataset, thus outperforming prior approaches in Raga recognition. / Master of Science / In Indian Classical Music (ICM), the Raga is a musical piece's melodic framework. The Raga is a unique concept in ICM, not fully described by any of the fundamental concepts of Western classical music. The Raga provides musicians with a melodic fabric, within which all compositions and improvisations must take place. Raga recognition refers to identifying the constituent Raga in an audio file, a challenging and important problem with several known prior approaches and applications in Music Information Retrieval. This thesis presents a novel approach to recognizing Ragas by representing this task as a document classification problem, solved by applying a deep learning technique. A digital audio excerpt is processed into a textual document structure, from which the constituent Raga is learned. Based on the evaluation with third-party datasets, our recognition approach achieves high accuracy, thus outperforming prior approaches.
3

Iodinated Pharmaceuticals as Precursors to Total Organic Halogen Formation in the Presence of Chlorinated Oxidants and Absence of Natural Organic Matter

Kumkum, Pushpita 20 September 2013 (has links)
No description available.
4

A ExpansÃo das Commodities e a Suposta DesindustrializaÃÃo na RegiÃo Nordeste do Brasil no PerÃodo 1991-2012 / A EXPANSÃO DAS COMMODITIES E A SUPOSTA DESINDUSTRIALIZAÃÃO NA REGIÃO NORDESTE DO BRASIL NO PERÃODO 1991-2012

Kamille LeÃo de Souza 27 August 2013 (has links)
nÃo hà / Nos dias atuais, à tema dos principais debates a desindustrializaÃÃo em curso nas economias que ainda nÃo atingiram alta renda per capita.VÃrios estudos foram realizados no Brasil sobre o assunto, mas a regiÃo Nordeste ainda carece de anÃlises nessa Ãrea. A hipÃtese central deste estudo à verificar se a economia nordestina se desindustrializou no perÃodo 1991-2012, com o crescimento contÃnuo de commodities na pauta de exportaÃÃes, aliado à maior participaÃÃo de produtos de conteÃdo tecnolÃgico mais relevante na pauta de importaÃÃes. A anÃlise foi realizada fazendo uso de dados da balanÃa comercial, exportaÃÃo e importaÃÃo, registrando a participaÃÃo das commodities e dos produtos industriais segundo a classificaÃÃo adotada pelo MDIC e OCDE (Alta, mÃdia-alta, mÃdia-baixa, baixa intensidade tecnolÃgica e produtos nÃo industrializados), do valor agregado pela indÃstria, pela participaÃÃo do emprego industrial no total e a renda (PIB). Para tal fim, foram calculados indicadores do comÃrcio exterior (Ãndice de ConcentraÃÃo das ExportaÃÃes-ICX, Ãndice de ConcentraÃÃo das ImportaÃÃes-ICM, Ãndice de Vantagem Comparativa Revelada em relaÃÃo ao saldo comercial-VCR, Taxa simples de Cobertura das importaÃÃes-TC e o Ãndice de ComÃrcio IntraindÃstria- CII) e regredido um modelo economÃtrico para verificar vestÃgios de desindustrializaÃÃo concernente à produÃÃo industrial. Os resultados indicam que a pauta de exportaÃÃo nordestina passa por uma reprimarizaÃÃo, que associada à maior presenÃa de produtos industriais com maior conteÃdo tecnolÃgico nas importaÃÃes apresenta sinais de desindustrializaÃÃo. NÃo à possÃvel concluir, no entanto, que a economia nordestina padeÃa da doenÃa holandesa, pois, na anÃlise do emprego industrial e do valor adicionado pela indÃstria no total da economia, nÃo apareceram sinais de perda de importÃncia do setor industrial no total, resultados esses corroborados pelo modelo economÃtrico regredido. Alguns segmentos industriais (tÃxtil, vestuÃrio e acessÃrios, mÃquinas, aparelhos e materiais elÃtricos) expressam, contudo, uma tendÃncia decrescente na evoluÃÃo do Ãndice de produÃÃo fÃsica industrial, o que pode indicar perda relativa desses ramos especificamente. / Nos dias atuais, à tema dos principais debates a desindustrializaÃÃo em curso nas economias que ainda nÃo atingiram alta renda per capita.VÃrios estudos foram realizados no Brasil sobre o assunto, mas a regiÃo Nordeste ainda carece de anÃlises nessa Ãrea. A hipÃtese central deste estudo à verificar se a economia nordestina se desindustrializou no perÃodo 1991-2012, com o crescimento contÃnuo de commodities na pauta de exportaÃÃes, aliado à maior participaÃÃo de produtos de conteÃdo tecnolÃgico mais relevante na pauta de importaÃÃes. A anÃlise foi realizada fazendo uso de dados da balanÃa comercial, exportaÃÃo e importaÃÃo, registrando a participaÃÃo das commodities e dos produtos industriais segundo a classificaÃÃo adotada pelo MDIC e OCDE (Alta, mÃdia-alta, mÃdia-baixa, baixa intensidade tecnolÃgica e produtos nÃo industrializados), do valor agregado pela indÃstria, pela participaÃÃo do emprego industrial no total e a renda (PIB). Para tal fim, foram calculados indicadores do comÃrcio exterior (Ãndice de ConcentraÃÃo das ExportaÃÃes-ICX, Ãndice de ConcentraÃÃo das ImportaÃÃes-ICM, Ãndice de Vantagem Comparativa Revelada em relaÃÃo ao saldo comercial-VCR, Taxa simples de Cobertura das importaÃÃes-TC e o Ãndice de ComÃrcio IntraindÃstria- CII) e regredido um modelo economÃtrico para verificar vestÃgios de desindustrializaÃÃo concernente à produÃÃo industrial. Os resultados indicam que a pauta de exportaÃÃo nordestina passa por uma reprimarizaÃÃo, que associada à maior presenÃa de produtos industriais com maior conteÃdo tecnolÃgico nas importaÃÃes apresenta sinais de desindustrializaÃÃo. NÃo à possÃvel concluir, no entanto, que a economia nordestina padeÃa da doenÃa holandesa, pois, na anÃlise do emprego industrial e do valor adicionado pela indÃstria no total da economia, nÃo apareceram sinais de perda de importÃncia do setor industrial no total, resultados esses corroborados pelo modelo economÃtrico regredido. Alguns segmentos industriais (tÃxtil, vestuÃrio e acessÃrios, mÃquinas, aparelhos e materiais elÃtricos) expressam, contudo, uma tendÃncia decrescente na evoluÃÃo do Ãndice de produÃÃo fÃsica industrial, o que pode indicar perda relativa desses ramos especificamente.
5

Migration to the Flipped Classroom – Applying a Scalable Flipped Classroom Arrangement

Jantos, Anne, Heinz, Matthias, Schoop, Eric, Sonntag, Ralph 09 May 2019 (has links)
Purpose – This paper is part of an extensive project1 which focusses on creating and implementing a scalable flipped classroom framework to broaden information and media competencies in university staff in Saxony. A flipped classroom arrangement with a sensible mix of multimedia tools promotes meaningful learning and lowers travel costs by avoiding content consumption in face-to-face time and instead offers content beforehand using various sources. This paper will in particular focus on the approach to gradually apply a flipped classroom arrangement to a B2B-Marketing course specifically designed for part-time students and use the implications to promote this method and further the step-by-step migration to the flipped classroom at universities in Saxony. Design/methodology/approach – Gathering information by reviewing previous experiences in E-Learning over the past decade, we were able to create an overview of how to approach part-time students and identified various concepts to create a more flexible and meaningful learning environment. We decided on a flipped classroom arrangement which offers time sensible teaching and promotes meaningful learning. A flipped classroom framework has been created which can be adjusted freely. Finally, we implemented the framework to a B2B-Marketing course by adapting it to the course content, time frame and attendance number. This procedure is designed to gradually increase usage of multi media tools and self efficacy and thereby steadily migrates the course to the flipped classroom. Originality/value – Focussing on part-time students’ needs and satisfying them with a flipped classroom arrangement is an entirely new approach. This project connects parttime- learning with online learning in a yet unprecedented manner. Practical implications – This paper describes the project’s two main outcomes. Firstly, an independent scalable framework which can be adapted to different learners’ and teachers’ needs. Secondly, the application strategy is described in detail and offers explicit indications and methods to implement the flipped classroom gradually. Also, there will be an evaluation which will be interpreted and summarized in a guideline as well as patterns and lessons learned. In general, this project aims to broaden media and information competencies and encourage and strengthen collaboration in higher education in Saxony.
6

Business plan for ICM (Pty) Ltd

Van Metzinger, Willem Antonie 12 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: This business plan is a document focussing on creating a business which truly embrace the "New Economy", and by using technology, crafting a strategy which can ensure that the company become successful, and a market leader in the field of civil engineering. The plan focuses on two separate entities. Firstly, building a business by using current techniques in evaluating the industry, developing an initial strategy, and setting the tone for crafting a strategy in the future which will fulfil the goals and objectives of the company, thereby reaching it's initial vision. It use a combination of analysis, creativity, and learning to develop a market leader which has the main focus of being innovative, serving it's clients with service quality, becoming the leader in it's field. A key success factor interaction diagram was developed and combined with an industry value chain to change the operational process into a new market orientated process enabling the company to achieve it's goals. Secondly, the focus is to create wealth for its stakeholders. In that regard the current system in the engineering industry was challenged. New operational processes were developed which is in line with the company vision and mission. These processes was correlated with the financial structure and projections made to ensure that the crafting of the strategy will be done in a systematic way, but always focussing on the goals and objectives of the company. Finally, an implementation plan is developed which is a crucial action plan to ensure success in the future. / AFRIKAANSE OPSOMMING: Die doelwit van hierdie besigheidsplan is om die basis te lê om 'n suksesvolle markleier in die siviele ingenieurs bedryf te word. Dit is gebaseer op die beginsels van die "Nuwe Ekonomie". Tesame met daardie beginsels word tegnologie gebruik om 'n strategie te ontwikkel en te vorm soos wat die maatskappy groei. Die plan fokus op twee hoofdele. Eerstens, om 'n maatkappy van statuur te ontwikkel. Huidige analitiese tegnieke om die industrie te evalueer is gebruik om 'n basis strategie te ontwikkel. Hierdie basis strategie sal dan uitgebrei word soos wat die maatskappy ontwikkel deur te fokus op sy doelwitte en sy visie. Deur analise, kreatiwiteit en kundigheid te kombineer word gepoog om te fokus op innovering en kwaliteit wat die kwaliteite is wat benodig word om 'n mark leier te word. 'n Sleutel sukses faktor interaksie diagram is ontwikkel wat tesame met 'n industrie waarde ketting gebruik is om die huidige operasionele prosesse te verander in nuwe mark gerigte prosesse. Die stelsel is die fondasie wat gelê word om die maatskappy doelwitte te bereik. Tweedens, word daar gefokus om rykdom te skep vir die aandeelhouers asook die maatskappye wat deel vorm van die lCM netwerk. Die huidige stelsels in die industrie was ge-evalueer en afgebreek totdat nuwe stelsels ontwikkel is wat inpas in die visie en missie van die maatskappy. Dit is gekorreleer met 'n finansiële model en inkomste en uitgawe projeksies vir die toekoms. Die projeksies is gebaseer op 'n geleidelike ontwikkeling van die stelsels totdat daar na drie jaar 'n gevestigde wereldklas stelsel in plek is. Laastens word afgesluit met 'n aksie-plan wat noodsaaklik is vir effektiewe implimentering van die besigheidsplan.
7

Communicating the Australian Coast: Communities, Cultures and Coastcare

Foxwell-Norton, Kerrie-Ann, na January 2007 (has links)
In Australia, Integrated Coastal Zone Management (ICM) is the policy framework adopted by government to manage the coastal zone. Amongst other principles, ICM contains an explicit mandate to include local communities in the management of the coastal zone. In Australia, the Coastcare program emerged in response to international acceptance of the need to involve local communities in the management of the coastal zone. This dissertation is a critical cultural investigation of the Coastcare program to discover how the program and the coastal zone generally, is understood and negotiated by three volunteer groups in SE Queensland. There is a paucity of data surrounding the actual experiences of Coastcare volunteers. This dissertation begins to fill this gap in our knowledge of local community involvement in coastal management. My dissertation considers the culture of Coastcare and broadly, community participation initiatives. Coastcare participants, government policymakers, environmental scientists, etc bring to their encounter a specific ‘way of seeing’ the coast – a cultural framework – which guides their actions, ideas and priorities for the coastal zone. These cultural frameworks are established and maintained in the context of unequal relations of power and knowledge. The discourses of environmental science and economics – as evidenced in the chief ICM policy objective, Ecologically Sustainable Development (ESD) – are powerful knowledges in the realm of community participation policy. This arrangement has serious consequences for what governments and experts can expect to achieve via community participation programs. In short, the quest for ‘power-sharing’ with communities and ‘meaningful participation’ is impeded by dominant scientific and economic cultures which act to marginalise and discredit the cultures of communities (and volunteers). Ironically enough, the lack of consideration of these deeper relations of power and knowledge means that the very groups (such as policymakers, environmental scientists, etc) who actively seek the participation of local communities, contribute disproportionately to the relative failure of community participation programs. At the very least, as those in a position of power, policymakers and associated experts do little to enhance communication with local communities. To this situation add confusion wrought by changes in the delivery of the Coastcare program and a lack of human and financial resources. From this perspective, the warm and fuzzy sentiment of Coastcare can be understood as the ‘Coastcare of neglect’. However, the emergence of community participation as ‘legitimate’ in environmental policymaking indicates a fissure in the traditional power relations between communities and experts. Indeed the entry of ‘community participation policy’ is relatively new territory for the environmental sciences. It is this fissure which I seek to explore and encourage via the application of a cultural studies framework which offers another ‘way of seeing’ community participation in coastal and marine management and thereby, offers avenues to improve relations between communities and experts. My fieldwork reveals a fundamental mismatch between the cultural frameworks which communities bring to the coast and those frameworks embodied and implemented by the Coastcare program. Upon closer examination, it is apparent that the Coastcare program (and community participation programs generally) are designed to introduce local ‘lay’ communities to environmental science knowledge. Local coastal cultures are relegated to the personal and private realm. An excellent example of this is the scientifically oriented ‘eligible areas for funding’ of the Coastcare program. The volunteers consulted for this project emphasized their motivation in terms of ‘maintaining the natural beauty of the coast’ and ‘protecting a little bit of coast from the rampant development of the coastal zone’. Their motivations were largely the antithesis of ESD. They understood their actions as thwarting the negative impacts of coastal development – this occurred within a policy framework which accepted development as fait d’accompli. Australia’s nation of coastal dwellers may not know a lot about ‘coastal ecologies’ but they do know the coast in other ways. Community knowledge of the coast can be largely accounted for in the phrase, ‘Australian beach culture’. Serious consideration of Australian beach culture in environmental policy is absent. The lack of attention to this central tenet of the Australian way of life is because, as a concept and in practice, beach culture lacks the ‘seriousness’ and objectivity of environmental science knowledge – it is about play, hedonism, holidays, spirituality, emotion and fun. The stories (including Indigenous cultural heritage) which emerge when Australians are asked about their ‘beach cultural knowledge’ – historical and contemporary experiences of the Australian coast – await meaningful consideration by those interested in communicating with Australian communities living on the coast. This ‘cultural geography’ is an avenue for policymakers to better communicate and engage with Australian communities in their quest to increase participation in, or motivate interest in community coastal management programs.
8

Electroencéphalographie et Interfaces Cerveau-Machine : nouvelles méthodes pour étudier les états mentaux

Grandchamp, Romain 02 October 2012 (has links) (PDF)
Avec les avancées technologiques dans le domaine de l'imagerie cérébrale fonctionnelle et les progrès théoriques dans la connaissance des différents éléments neuro-physiologiques liés à la cognition, les deux dernières décennies ont vu l'apparition d'interfaces cerveau-machine (ICM) permettant à une personne d'observer en temps réel, ou avec un décalage qui se limite à quelques secondes, sa propre activité cérébrale. Le domaine clinique en général, et plus particulièrement celui de la neuropsychologie et des pathologies conduisant à un handicap moteur lourd, pour lesquels les applications potentielles sont nombreuses qu'elles soient thérapeutiques ou en vue d'une réhabilitation fonctionnelle, a constitué un moteur important de la recherche sur ce nouveau domaine des neurosciences temps réel. Parmi ces applications, le neurofeedback, ou neurothérapie, qui vise l'acquisition par le sujet du contrôle volontaire de certains aspects de son activité cérébrale en vue de les amplifier ou au contraire les diminuer dans un but thérapeutique, voire d'optimisation cognitive, représente une technique prometteuse, alternative aux thérapies et traitements médicamenteux. Cependant, la validation de ce type d'intervention et la compréhension des mécanismes mis en jeux en sont encore à leurs balbutiements. L'entraînement par neurofeedback est souvent long, pouvant s'étaler sur plusieurs semaines. Il est donc très probable que ce type de rééducation cérébrale sollicite des phénomènes de plasticité qui s'inscrivent dans une dynamique lente, et de ce fait, requiert une durée relativement longue d'entraînement pour atteindre les effets à long terme recherchés. Cependant, à cela peuvent s'ajouter de nombreux éléments perturbateurs qui pourraient être à l'origine de la difficulté de l'apprentissage et des longs entraînements nécessaires pour obtenir les résultats attendus. Parmi eux, les perturbations qui viennent déformer le signal enregistré, ou les éléments artefactuels qui ne font pas partie du signal d'intérêt, sont une première cause potentielle. Le manque de spécificité fonctionnelle du signal retourné au sujet pourrait en constituer une deuxième. Nous avons d'une part développé des outils méthodologiques de traitement du signal en vue d'améliorer la robustesse des analyses des signaux EEG, principalement utilisés jusqu'à maintenant dans le domaine du neurofeedback et des ICM, face aux artefacts et au bruit électromagnétique. D'autre part, si l'on s'intéresse au problème de la spécificité fonctionnelle du signal présenté au sujet, des études utilisant l'IRM fonctionnelle ou des techniques de reconstruction de sources à partir du signal EEG, qui fournissent des signaux ayant une meilleure spécificité spatiale, laissent entrevoir de possibles améliorations de la vitesse d'apprentissage. Afin d'augmenter la spécificité spatiale et la contingence fonctionnelle du feedback présenté au sujet, nous avons étudié la stabilité de la décomposition de l'EEG en différentes sources d'activité électrique cérébrale par Analyse en Composantes Indépendantes à travers différentes séances d'enregistrement effectuées sur un même sujet. Nous montrons que ces décompositions sont stables et pourraient permettre d'augmenter la spécificité fonctionnelle de l'entraînement au contrôle de l'activité cérébrale pour l'utilisation d'une ICM. Nous avons également travaillé à l'implémentation d'un outil logiciel permettant l'optimisation des protocoles expérimentaux basés sur le neurofeedback afin d'utiliser ces composantes indépendantes pour rejeter les artefacts en temps réel ou extraire l'activité cérébrale à entraîner. Ces outils sont utiles dans le cadre de l'analyse et de la caractérisation des signaux EEG enregistrés, ainsi que dans l'exploitation de leurs résultats dans le cadre d'un entraînement de neurofeedback. La deuxième partie de ce travail s'intéresse à la mise en place de protocoles de neurofeedback et à l'impact de l'apprentissage. Nous décrivons tout d'abord des résultats obtenus sur une étude pilote qui cherche à évaluer chez des sujets sains l'impact d'un protocole de neuro-feedback basé sur le contrôle du rythme Mu. Les changements comportementaux ont été étudiés à l'aide d'un paradigme de signal stop qui permet d'indexer les capacités attentionnelles et d'inhibition de réponse motrice sur lesquelles on s'attend à ce que l'entraînement ICM ait une influence. Pour clore cette partie, nous présentons un nouvel outil interactif immersif pour l'entraînement cérébral, l'enseignement, l'art et le divertissement pouvant servir à évaluer l'impact de l'immersion sur l'apprentissage au cours d'un protocole de neurofeedback. Enfin, les perspectives de l'apport des méthodes et résultats présentés sont discutées dans le contexte du développement des ICMs de nouvelle génération qui prennent en compte la complexité de l'activité cérébrale. Nous présentons les dernières avancées dans l'étude de certains aspects des corrélats neuronaux liés à deux états mentaux ou classes d'états mentaux que l'on pourrait qualifier d'antagonistes par rapport au contrôle de l'attention : la méditation et la dérive attentionnelle, en vue de leur intégration à plus long terme dans un entraînement ICM par neurofeedback.
9

Molecular characterization of oct4-expressing yolk sac endoderm stem cell lines.

Debeb, Bisrat Godefay 15 May 2009 (has links)
The extraembryonic endoderm (XEN) defines the yolk sac, a set of membranes that provide essential support for mammalian embryos. Recently, the committed XENprecursor was identified in the embryonic Inner Cell Mass (ICM) as a group of cells that intermingles with the closely related, anatomically indistinguishable epiblast (EPI)- precursor that gives rise to the fetus. In vitro, the EPI-precursor is represented by the well-known embryonic stem (ES) cell lines, but cell lines representing the XENprecursor are not known. Furthermore, since the XEN-precursor cells were discovered only very recently, the unexpected fact that they express the key pluripotency marker Oct4 has not been explored. Recently, however, our laboratory has isolated rat XEN cell lines that express Oct4, leading to the following two questions: (i) Do these new XEN cell lines represent XEN-precursor cells? (ii) Is their Oct4 expression regulated similarly as previously known from ES cells? These two questions are addressed here by lineage marker and reporter gene analyses. Whole culture analyses showed that rat XEN cell lines expressed markers of all XEN stages including XEN-precursor, primitive endoderm (PrE) and/or visceral endoderm (VE), and parietal endoderm (PE) but trophoectoderm and EPI-precursor markers were missing. In line with this, immunocytochemistry demonstrated heterogeneity and directly visualized the XEN-precursor, PrE/VE, and PE subpopulations. Low-density plating and time-dependent immunocytochemistry on resulting colonies strongly suggested that XEN-precursor cells generate the other XEN stages. Moreover, by analyzing single-cell derived clones, it was shown that culture heterogeneity results from the self-renewal and differentiation of a single cell. Reporter gene analyses using the 5’ regulatory region of the mouse Oct4 gene revealed that a DNA fragment containing the previously described distal enhancer drove reporter gene expression only in ES cells whereas inclusion of an upstream fragment led to high expression in both mouse ES and rat XEN cells. In conclusion, our rat XEN cell lines contain XEN-precursor cells that differentiate extensively, providing for the first time an in vitro model that mimics the natural process of early XEN differentiation. In addition, they regulate Oct4 gene transcription differently than ES cells suggesting heterogeneous Oct4 regulation within the mammalian ICM.
10

Commande robuste d'un effecteur par une interface cerveau machine EEG asynchrone / Robust control of an actuator by EEG based asynchronous BCI

Barachant, Alexandre 28 March 2012 (has links)
Cette thèse a pour but le développement d’une Interface cerveau-machine (ICM) à partir de la mesure EEG,permettant à l’utilisateur de communiquer avec un dispositif externe directement par l’intermédiaire de son activité cérébrale. Ces travaux ont été menés avec comme ligne directrice le développement d'un système d'ICM utilisable dans un contexte de vie courante, le but étant de réaliser une ICM simple d'utilisation, robuste et ergonomique, permettant le contrôle d'un effecteur avec un temps de calibration minimal.Un brain-switch ou interrupteur cérébral a été réalisé et permet à l'utilisateur d'envoyer une commande binaire. La réalisation d'une telle ICM implique le développement d'algorithmes robustes et leurs mises en œuvre expérimentales. Les travaux réalisés comportent deux volets, l'un concerne le développement de nouveaux algorithmes, l'autre concerne la réalisation de campagne de tests. / This thesis presents the development of a Brain computer Interface (BCI) based on EEG signal, allowing its user to communicates with an external device solely by the mean of brain activity. This work as been conduct with the goal of designing a robust, ergonomic and easy to use BCI system for real life applications.In this context, a brain-switch has been developed, allowing it's user to send a binary command to a homeautomation system. This goal can only be achieved by developing new methodologies and algorithms, while testing them on real life experiments. Therefore, this works is two part, the first one is focus on the design of new algorithms, the secondon the design of experimental paradigm.

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