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1
Janati, Hicham. "Advances in Optimal transport and applications to neuroscience." Electronic Thesis or Diss., Institut polytechnique de Paris, 2021. http://www.theses.fr/2021IPPAG001.
Abstract:
Les dispositifs d'imagerie cérébrale peuvent donner un aperçu de l'activité neuronale à plusieurs endroits et points dans le temps. En pratique, les études d'imagerie cérébrales sont généralement menées pour plusieurs personnes suivant le même protocole expérimental. L'inférence des régions actives du cerveau est un problème inverse mal posé qui ne peut être résolu qu'en ajoutant des hypothèses a priori sur les solutions. Plusieurs hypothèses préalables ont été poursuivies dans la littérature, comme la favorisation des solutions parcimonieuses ou la résolution du problème pour plusieurs sujets à la fois. Cependant, aucune ne profite de la géométrie spatiale du problème. Le but de cette thèse est d'exploiter au maximum les aspects multisujets, spatiaux et temporels des données de magnétoencéphalographie pour améliorer le conditionnement du problème inverse. À cette fin, nos contributions s'articulent autour de trois axes : le transport optimal (OT), la régression multi-tâches parcimonieuse et les séries temporelles. En effet, la capacité de l'OT à mesurer les disparités spatiales entre les distributions le rend très bien adapté à la comparaison et l'aggrégation des cartes d'activation neurales en fonction de leur forme et de leur emplacement sur la surface du cortex cérébral. Pour des raisons numériques, on utilise la formulation entropique du transport optimal, qui, selon nous, comporte deux pièces manquantes importantes. D'un point de vue théorique, elle n'a aucune expression analytique à ce jour, et d'un point de vue pratique, l'entropie conduit à une augmentation significative de la variance, phénomène connu sous le nom de biais entropique. Nous complétons ce puzzle en étudiant les Gaussiennes multivariées pour lesquelles nous découvrons une forme close de l'OT entropique et proposons des algorithmes débiaisés pour calculer des barycentres de transport optimal rapides et précis. Ensuite, nous définissons une pénalité multitâche basé sur l'OT et des pénalités de parcimonie pour résoudre le problème inverse pour plusieurs sujets afin de promouvoir des solutions cohérentes sur le plan spatial. Nos résultats sur des données réelles mettent en évidence les avantages de l'utilisation de l'OT comme régularisation par rapport aux pénalités de régression multitâches classiques. Enfin, nous proposons une nouvelle divergence pour comparer et moyenner des données spatio-temporelles basée sur un alignement temporel entre des observations spatialement similaires, le tout via un algorithme rapide et adapté aux GPUsBrain imaging devices can provide a glimpse at neural activity in multiple spatial locations and time points. Moreover, neuroimaging studies are usually conducted for multiple individuals undergoing the same experimental protocol. Inferring the underlying sources is a challenging inverse problem that can only be tackled by biasing the solutions with prior domain knowledge. Several prior hypotheses have been pursued in the literature such as promoting sparse over dense solutions or solving the problem for multiple subjects at once. However, none take advantage of the particular spatial geometry of the problem. The purpose of this thesis is to exploit the multi-subject, spatial and temporal aspects of magneto-encephalography data as much as possible to improve the conditioning of the inverse problem. To that end, our contributions revolve around three axes: optimal transport (OT), sparse multi-task regression and time series. Indeed, the ability of OT to capture spatial disparities between measures makes it very well suited to compare and average neural activation patterns based on their shape and location over the cortical surface of the brain. For the sake of scalability, we take advantage of the entropic formulation of optimal transport, which we argue has two important missing pieces. From a theoretical perspective, it has no closed form analytical expressions, and from a practical perspective, entropy leads to a significant increase in variance known as "entropic bias". We complete this puzzle by studying multivariate Gaussians for which we uncover an entropic OT closed form and propose "debiased" algorithms to compute fast and accurate optimal transport barycenters. Second, we define a multi-task prior based on OT and sparse penalties to jointly solve the inverse problem for multiple subjects to promote spatially coherent solutions. Our real data experiments highlight the benefits of using OT as a prior over classical multi-task regression penalties. Finally, we propose a loss function to compare and average spatio-temporal data that computes temporal alignments across spatially similar observations of the data via a fast GPU friendly algorithm
2
Dumenil, Sylvie. "Influence de concentrations subinhibitrices d'amikacine sur l'activité élastolytique de"Pseudomonas aeruginosa" IFO 3455." Paris 5, 1991. http://www.theses.fr/1991PA05P101.
3
Farghal, Aser Soliman Ahmed. "Physiological MR imaging of small bowel : implementation, validation and interpretation." Thesis, University of East Anglia, 2011. https://ueaeprints.uea.ac.uk/34255/.
4
Holmes, Christopher. "Economistic fallacies in contemporary capitalism : a Polanyian analysis of regimes of marketised social protection." Thesis, University of Warwick, 2010. http://wrap.warwick.ac.uk/34555/.
Abstract:
Karl Polanyi used the notion of economistic fallacy in order to flag up the way in which formal definitions of the economy – rooted in the assumption of economising, self-interested market behaviour – were routinely applied as universal and rational by economists, political scientists, policy makers and in general public discourse. This thesis is a critical re-application of the notion of economistic fallacy in theoretical, historical and contemporary perspective. I argue that, although Polanyi’s broad generalisations are unsuitable for contemporary analysis, the same basic type of fallacy can be observed in various specific policy settings. Roughly speaking, the thesis comprises two halves. In the first, I focus on theoretical matters, arguing for a consideration of Polanyi specifically as a political economist of ideas. This, I argue, gets us closer to some of Polanyi’s most interesting analytical intentions whilst freeing us from some of the apparent ontological contradictions latent in his various texts. From there, I develop Polanyi’s insights on the role of ideas in capitalist development, foregrounding the notion of economistic fallacy as a key conceptual device. In the second half of the thesis, I apply this analysis over three case studies, one on global financial regulation, one on climate change and one on welfare provision in the UK. These areas are chosen as contemporary reflections of the three ‘fictitious commodities’ that Polanyi identified as uniquely important loci of economistically fallacious logics, namely money, land and labour. In each case, I note how specific versions of economistic fallacy have guided policies that aim to deliver forms of social protection via market mechanisms and market actors – what I call ‘marketised social protection’. This is in distinction to the straightforward (often state-led) societal self-protection that Polanyi and latter-day Polanyians have typically focused upon. I argue that the policies discussed are economistically fallacious to the extent that they rely on unrealistic, overly rationalist assumptions about the nature of society, the natural environment and people, respectively. I show instead how the dynamics of capital accumulation that such regimes serve to legitimate and protect – dynamics that I refer to as forms of ‘market self-protection’ – act to continually undermine the success of such policy programmes. This, I argue, is a distinctive tension in the ideational and material landscape of contemporary capitalism.
5
Eaton, Natasha Jane. "Imaging Empire : the trafficking of art and aesthetics in British India c.1772 to c.1795." Thesis, University of Warwick, 2000. http://wrap.warwick.ac.uk/34755/.
Abstract:
This dissertation explores the complex entanglements of an artistic traffic between two distinct 'visual economies' in eastern India, c.1772-c.1795. Both late Mughal and early colonial cultures were undergoing transformation, to the extent that during this era the nascent colonial artistic diaspora collapsed. Three inter-related areas will be interrogated: the prestation and commercial circulation of imagery between London, Calcutta and Murshidabad, the dichotomies of political and aesthetic spheres, and colonial representations of late Mughal culture as embroiled by such frameworks. Chapter one examines India-painted subjects in a metropolitan aesthetic sphere, thus acting as crucial juxtaposition for the refiguration of British art in Calcutta, which is the subject of the following section. Hastings' regime wielded British art as part of an intensely spectacular colonial governmentality, but his successor Cornwallis, took a tougher line with devastating effect. A diversity of competing, derivative idioms ousted professional colonial painting forever; its artistic schema penetrated to 'grass-roots' level through the creation of a 'Company School' which transposed the practice of the patua caste. Chapters five to seven investigate nawabi perceptions of British imagery. Hastings introduced the gifting of large-scale portraits; artefacts ill-suited to Indian interiors and aesthetic interiority - perhaps not even viewed as 'art'. The final chapter, through representations of the nawabs of Murshidabad and Lucknow, traces the evolution of British pictures as accoutrements of Mughal sovereignty. By 1795 both courts possessed permanent if 'hybrid' expositions of colonial imagery which transgressed established Indian and British classifications, as well as indicating more profound redefinitions of Indian comportment, consumption and taste. The intersection of 'visual economies' by way of an exploration of diverse zones of transculturation and processes of translation, provides a vital lens for recovering Indian and British agency - both elite and subaltern, in the oft-uneasy formation of a colonial aesthetic forum.
6
Chryssochoidis, George. "Rolling out new products across international markets : causes of delays." Thesis, University of Warwick, 1997. http://wrap.warwick.ac.uk/34655/.
Abstract:
The problem of delays in product rollout becomes more unwieldy for new products that are being launched across many countries. This concern rises when firms operate in rapid technological change and high internationalisation business environments. This study aims to form an empirically based body of knowledge about rollout of new products across international markets, build strong theory and provide insights for better practice. The study focuses on both static and dynamic aspects of the management of new product rollout across international markets. The investigation considers an extensive set of variables describing the company's external and internal environment, as well as the company's action across borders. It attempts more precisely to identify: - whether timeliness in new product rollout relates to new product success; - whether companies roll out new products across their international markets simultaneously or sequentially; and - the factors that lead to delay in rollout schedules and their interaction. A six-phase research methodology was designed and implemented. These phases were: (1) a review of literature across several streams of research; (2) a pilot telephone interview study; (3) exploratory interviews in 6 companies and a preliminary cross-case analysis; (4) the refinement of methodological and theoretical framework issues; (5) an additional series of research interviews in 24 more companies; and (6) a second cross-case analysis. These were followed by the formulation of a model and the estimation of the magnitude of direct, indirect and total effects of each factor upon rollout timeliness. The main findings were: - Timely rolled-out projects were far more successful than delayed rolled-out projects. - Sequential new product rollouts were more frequent than simultaneous ones. Delays were consistently featured in the cases of sequential new product rollouts. - The main factors that lead to delay in rollout schedules were: insufficiency of marketing and technological resources, poor internal communications between the HQ and the country markets, lack of synergies in product handling by the sales force in both the HQ and the country markets, lack of synergies in customer familiarity with the product, lack of proficiency in the new product development process and a deficient product.
7
Goff, M. "A critical investigation of electronic patient records in the NHS in England : tracing an elusive object through its actor-network." Thesis, University of Salford, 2014. http://usir.salford.ac.uk/34355/.
Abstract:
This study is a critical investigation of electronic patient records in the National Health Service in England. It explores whether EPRs benefit clinicians in the context of a technology that has been explicitly designed to fulfil multiple purposes, both clinical and non-clinical, and is critical in its motivation to challenge their apparent sense of inevitability. Against the backdrop of a government vision of a nationally networked EPR the research takes a meso level perspective using primary data from interviews with users across multiple NHS Trusts and healthcare settings. The study uses Actor-Network Theory from the outset as both a methodological and theoretical approach with the aim to be revelatory about the interests at work in sustaining this technology and to question whether clinicians bear the costs of network-building for the EPR. This has shaped the trajectory of the research, which is as a consequence highly reflexive and in which theoretical and methodological concerns are given equal weight to investigation of EPRs. Whilst EPRs undoubtedly benefit clinicians fundamentally through improved access to patient information, benefits are constrained by material and social interests that reproduce existing relations. In particular, non-clinical agendas are strongly inscribed within EPRs, reshaping clinical work practices by defining what may and must be recorded, and shifting attention within clinical care. A performative conception of EPRs acknowledges the messy and multiple realities and enables theorisation of the technology as complicit in a reshaping of reality towards informatized healthcare. EPRs mediate a quantification of clinical practice that implies additional work for clinicians, and new regimes of control based around recording in the EPR. The study paints a complex and subtle picture of the use of EPRs by mapping its actor-network through the experiences of users and conceptualising the EPR as emerging from a messy, heterogeneous network of socio-material relations.
8
Kaewkangsadan, Viriya. "Evaluation of immune cell infiltrates and expression of cytokines/biological molecules in the microenvironment of tumours and tumour-draining axillary lymph nodes in patients with large and locally advanced breast cancers undergoing neoadjuvant chemotherapy : crucial contribution to immune-mediated tumour cell death." Thesis, University of Nottingham, 2016. http://eprints.nottingham.ac.uk/34155/.
Abstract:
Background: Neoadjuvant chemotherapy (NAC) is being used as first line treatment in women with large and locally advanced breast cancers (LLABCs). However, the response to NAC is difficult to predict. Growing evidence suggests that these patients are immunosuppressed and that circulating immunosuppressive regulatory cells and humoral factors affect the response to NAC. We explored the possible role of the in situ tumour immune milieu in inducing and affecting the responses to NAC, and the contribution of concomitant systemic circulating regulatory cells. Methods: Paraffin-embedded breast cancers and ipsilateral axillary lymph nodes (ALNs) from pre- and post-NAC samples of a cohort of 33 women with LLABCs, 16 of whom had their blood regulatory cells previously investigated. Various immune cell infiltrations and expression of cytokines/biological molecules in the specimens were studied using appropriate monoclonal antibodies and immunohistochemistry. Statistical analysis was carried out using non-parametric tests with SPSS version 21. Results: High levels of pre-NAC tumour-infiltrating lymphocytes (TILs) (p < 0.001) and subsets of CD4⁺T cells (intratumoural, p=0.023; peritumoural, p=0.001), CD8+T cells (intratumoural, p=0.008; peritumoural, p=0.002) and CD56⁺NK cells (intratumoural, p=0.001; peritumoural, p < 0.001) were significantly associated with a pathological complete response (pCR). High levels of CD163⁺macrophages were also significantly associated with a good pathological response (p=0.004) and pCR (p=0.008). There was a positive correlation between the CD8:FOXP3 ratio and grade of pathological response. In multivariate analyses, TILs and peritumoural CD56+NK cells were found to be independent predictive factors for pCR. There was a significantly high expression of IL-10 in post-NAC breast specimens with poor responses to NAC (p < 0.001). NAC significantly reduced infiltrating T regulatory cells (Tregs) (p=0.001) and PD1⁺T cells (p=0.005), as well as expression of IL-4 (p=0.016). There was no significant difference between the percentages (%) of immune cells present in ALNs with or without metastases but there was a T helper-2 cytokine polarisation in metastatic ALNs. Metastatic ALNs with a high % of CD8+T cells (p=0.048) and low % of FOXP3+Tregs (p=0.019) were significantly associated with an ALN pCR. There was a significantly positive correlation between circulating and intratumoural infiltrating Tregs following NAC (p=0.003). Conclusions: The tumour immune microenvironment is a key factor in achieving a good pathological response with NAC. Tumour and blood immune parameters may be clinically useful in identifying women with LLABCs likely to respond to NAC. Our findings also suggest that the beneficial effects of NAC are mediated via modulation of anticancer immunity, in particular by reduction of T regulatory cells and immunosuppressive humoral factors.
9
Mewar, Devesh. "Studies on autoantigens in rheumatoid arthritis." Thesis, University of Sheffield, 2003. http://etheses.whiterose.ac.uk/3455/.
Abstract:
This thesis describes the use of phage display for the isolation of autoantigens in rheumatoid arthritis. The potential of the technology is demonstrated by the isolation of an autoantigen, eukaryotic translation elongation factor 1a1 (eEF 1 (x 1)) from a fibroblast cDNA library using rounds of selective enrichment with IgG from RA patients. Subsequently in order to isolate joint-specific antigens a phage-displayed cDNA library from rheumatoid pannus was generated and screened with analogous procedures. From the clones isolated, putative candidate autoantigens were identified. The presence of anti- eEF 1a1 autoantibodies in approximately 20% of patients with RA was confirmed and extended in larger panels of sera, and the finding of anti-eEF la1 shown to be relatively specific for RA. In contrast autoantibodies to the activation-induced negative regulator of T cells, CTLA-4 were not found in contrast to a previous report. The relevance of these findings for the use of antibodies in the diagnosis and prediction of disease characteristics in RA are discussed.
10
Freier, De Ferrari Luisa Feline. "A reverse migration paradox? : policy liberalisation and new south-south migration to Latin America." Thesis, London School of Economics and Political Science (University of London), 2016. http://etheses.lse.ac.uk/3455/.
Abstract:
In past decades, immigration policies in Latin America developed in stark contrast to other regions. Whereas most countries moved towards more restrictive policies, many Latin American countries liberalised their immigration policy frameworks and recently passed laws that expand individual rights in unprecedented ways. At the same time, migratory movements in Latin America are in flux, one of the most noteworthy recent developments being the increase in extra-continental immigration from Africa, Asia and the Caribbean. This PhD explores a reverse migration paradox inherent in the reciprocal causal relationship between immigration policy liberalisation and new south-south migration. The first paper uses a mixed approach of legal analysis and process tracing to show this paradox in the cases of Argentina, Brazil and Ecuador. It analyses the tension between liberal discourses and policies that invoke the universality of migrants’ rights and free human mobility, on the one hand, and the rejection of recently increasing irregular south–south migration on the other. Using a difference-in-difference design, the second paper tests the impact of Ecuador’s policy of visa freedom of 2008 on previously restricted countries in Asia, Africa and the Caribbean, and shows that immigration from these regions more than doubled. Qualitative findings confirm that visa freedom was the main determinant of migrants’ decision to move to Ecuador and further show great variance of migrant characteristics. The third paper is based on 35 in-depth interviews, which collectively demonstrate that perceived security threats of domestic and international political actors, which led to the partial reintroduction of tourist visa requirements for ten African and Asian countries by 2010, were closely intertwined with racism. Taken together, the three papers have important implications for the study of immigration policies, south-south migration and the securitisation of migration.
11
Barile, Giacomo. "Simulazione dello scenario di missione del volo inaugurale del lanciatore VEGA." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3455/.
12
Winter, Satine Hyacinth. "Navigating the battleground: autism policy and human rights for children with autism spectrum disorders in Australia." Thesis, Griffith University, 2017. https://doi.org/10.25904/1912/3455.
Abstract:
The purpose of this study was to explore the Helping Children With Autism (HCWA) package, which is a public website on Australian autism policy with a particular consideration of how the HCWA package positioned parents when they engaged with this federal government initiative. The study also aimed to examine how and to what extent the HCWA package aligned with international human rights standards using the Convention on the Rights of Persons with Disabilities. This study was underpinned by a theoretical framework that combined the sociology of Zygmunt Bauman and the models of disability (charity, medical, social, human rights) with human rights.
The nature and complexity of autism spectrum disorder (ASD) presents challenges to parents raising their child with ASD, which often results in uncertainty about their rights and responsibilities alongside those of the government, and State. In 2008 the Australian Government attempted to solve the policy problem of autism and implemented the HCWA package in response to parents’ pleas for help in raising their child with ASD (Palm Consulting Group, 2005, June 20). The HCWA package was the first autism specific policy in Australia and aimed to provide funding, support, and services for children with ASD and their families (Minister for Families Community Services and Indigenous Affairs, 2007). The HCWA package is currently being superseded by the rollout of the National Disability Insurance Scheme (NDIS) across Australia and hence the opportunity to benefit from a close exploration of the HCWA may contribute to this process.
Limited research evaluating the effectiveness of the HCWA package has been conducted. No study has evaluated the parent perspective on the HCWA initiative as a policy and there were insufficient studies of parents’ reactions to the HCWA package (Prior, Roberts, Rodger, & Williams, 2011; Wicks & O'Reilly, 2013; K. D. Wilson, 2013; K. D. Wilson & Watson, 2011). Moreover, there is limited research on disability policy compliance with human rights standards, especially in Australia. Research on the HCWA package is important because it has the potential to identify areas of strength and weakness from a consumer and human rights perspective and helps inform future government policies and initiatives such as the NDIS and to improve the quality of life for children with ASD.
A qualitative approach of Multimodal Critical Discourse Analysis (MCDA) was used to examine the HCWA package across three landing pages from two government departments: FaHCSIA and DEEWR. In 2013 data were selected from the HCWA package over several months during the implementation of the HCWA package across Australia. The researcher, as a parent of a child with ASD, selected and analysed the data to explore how the HCWA package positioned parents when they engaged with this federal government initiative. Kress and van Leeuwen’s (2006) grammar of visual design provided a framework to analyse online web content using the researcher as viewer of the policy. The e-government autism policy was further analysed in terms of web accessibility and compliance with regulatory guidelines for federal government department websites.
The findings from this study reveal that the Australian Government positioned parents of children with ASD as consumers of the product of autism policy, in this case the HCWA package. This positioning was framed within a discourse of charity and medical models of disability that viewed autism as a problem of the individual and provided charity through funding, supports, and services (e.g. medical and education professionals). The charity and medical models of disability were entwined within a broader discourse of power where the Australian Government had power, position, and authority as experts over parents of children with ASD. This unequal distribution of power added to the tensions within the autism community and the cycle of blame between parents and professionals.
Good parenting - as it was constituted by the HCWA package - involved being informed and educated and willing to follow the advice of the Australian Government. Good parents furthermore complied with traditional western gender roles where women were viewed as the primary caregivers and nurturers of children with ASD, particularly in the early years. The Australian Government also positioned parents as neoliberal citizens who were responsible for the success of raising their child with ASD and the outcomes of that child in life and within society. Lastly, the study found that the HCWA package did not align with all general principles of Article 3, Convention on the Rights of Persons with Disabilities and was thus regarded as indicative of a violation of human rights for children with ASD in Australia.
Based on these findings, the study presents recommendations concerning the parent-as-consumer role in autism policy in meeting the best interests and needs of children with ASD and their families, which also have relevance to the current transition to the NDIS in Australia. An eight-step model is proposed to improve parent information and health literacy on ASD, which is important for improving parent decision-making for their child with ASD. In particular, a newly framed human rights model of disability is recommended as a means of moving forward from the social model of disability in critical disability studies and for advancing the rights of children with ASD in theory and in practice.
13
Perella, Fiona M. "Exploring the experiences of fathers of children with a visible facial difference." Thesis, University of East London, 2013. http://roar.uel.ac.uk/3455/.
Abstract:
This study examined the experiences of fathers of children with a congenital visible facial difference (CVFD), focussing on cleft lip with/without palate (CLP). The face plays a central role in self-concept and social existence for humans and holds vast cultural significance. However, research has been slow to go beyond individual and address the significant wider impacts on the family. Fathers have been particularly neglected. This is surprising given the wealth of evidence regarding the important direct and indirect influences fathers have on child development. This study aimed to explore how men experience fatherhood in relation to having a child with CLP, their perceived roles within the family and their experiences of support. The study employed a qualitative methodology. Participants were recruited via a national charity and via Twitter. Individual, semi-structured interviews were conducted with eight fathers of children (under the age of ten) with CLP. The data were analysed using Interpretative Phenomenological Analysis, generating three super-ordinate themes: ‘Loss of the perfect child’; ‘The power of ‘normality’; and ‘The expectations and roles of fathers’. Participants faced challenges in managing intense and conflicting emotions, with societal and personal conceptualisations of difference having a significant influence. They emphasised their roles as protector and supporter, highlighting the implications of successfully fulfilling these or not. Feeling excluded, insignificant and undersupported were prevalent issues. Support was derived from partners, and selfmanagement strategies (e.g. avoidance, focussing on practicalities) were identified. Unexpected (mainly positive) outcomes of CLP were also acknowledged. The findings are discussed in relation to the literature on the lived experiences of fathers of children with CLP, other CVFDs and other conditions where relevant. Implications for future research and clinical practice are considered, e.g. taking an actively inclusive approach with fathers, and offering opportunities to speak with a psychologist away from the multidisciplinary team spotlight.
14
Sapienza, Maria Rosaria <1979>. "SNPs array karyotyping reveals recurrent lesions in primary myelofibrosis." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3455/.
15
Jain, Nibha. "Exploring interactive tangrams for teaching basic school physics." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34755.
Abstract:
This Thesis explores the application of Tangible User Interfaces to Education. For this, a research study was conducted by building and testing an interactive game called Tangram Bridge. This Tangram based game was designed to teach players about basic physics principles such as balance, friction and motion on inclined planes.
The focus of this Tangram Bridge is middle school physics, and therefore concerns children aged 11 years and up, their instructors and care givers. This research also lays a lot of emphasis on constructive play amongst children.
Tangram Bridge is a versatile platform that can be scaled for younger or older populations
A comparative study of existing Tangible User Interfaces ( TUIs) revealed opportunity spaces for this project. Through a compilation of related research in the fields of education, hands on learning, Tangible interaction and understanding play and learning amongst children, the constructionist views on learning are explored as guidelines for the design of this study.
Through the analysis of comparative research studies, trends on TUI with relation to education emerged, informing the design process for Tangram Bridge.
This research study discusses the application of Tangible user interfaces to education. It combines the research data collected through market research, user testing and literature reviews to explore the efficacy of TUI as teaching tool for abstract concepts that require imagination and experimentation.
16
Song, Jin E. "Hierarchical multiscale modeling of Ni-base superalloys." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34855.
Abstract:
Ni-base superalloys are widely used in hot sections of gas turbine engines due to the high resistance to fatigue and creep at elevated temperatures. Due to the demands for improved performance and efficiency in applications of the superalloys, new and improved higher temperature alloy systems are being developed. Constitutive relations for these materials need to be formulated accordingly to predict behavior of cracks at notches in components under cyclic loading with peak dwell periods representative of gas turbine engine disk materials. Since properties are affected by microstructure at various length scales ranging from 10 nm tertiary γ' precipitates to 5-30 μm grains, hierarchical multiscale modeling is essential to address behavior at the component level.
The goal of this work is to develop a framework for hierarchical multiscale modeling network that features linkage of several fine scale models to incorporate relevant microstructure attributes into the framework to improve the predictability of the constitutive model. This hierarchy of models is being developed in a collaborative research program with the Ohio State University. The fine scale models include the phase field model which addresses dislocation dissociation in the γ matrix and γ' precipitate phases, and the critical stresses from the model are used as inputs to a grain scale crystal plasticity model in a bottom-up fashion. The crystal plasticity model incorporates microstructure attributes by homogenization.
A major task of the present work is to link the crystal plasticity model, informed by the phase field model, to the macroscale model and calibrate models in a top-down fashion to experimental data for a range of microstructures of the improved alloy system by implementing a hierarchical optimization scheme with a parameter clustering strategy. Another key part of the strategy to be developed in this thesis is the incorporation of polycrystal plasticity simulations to model a large range of virtual microstructures that have not been experimentally realized (processed), which append the experimentally available microstructures. Simulations of cyclic responses with dwell periods for this range of virtual (and limited experimental) polycrystalline microstructures will be used to (i) provide additional data to optimize parameter fitting for a microstructure-insensitive macroscopic internal state variable (ISV) model with thermal recovery and rate dependence relevant to the temperatures of interest, and (ii) provide input to train an artificial neural network that will associate the macroscopic ISV model parameters with microstructure attributes for this material. Such microstructure sensitive macroscopic models can then be employed in component level finite element studies to model cyclic behavior with dwell times at smooth and cracked notched specimens.
17
Alsenani, Qusai. "The Role of hhbp in Heme Uptake in Haemophilus ducreyi." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/34155.
Abstract:
Haemophilus ducreyi is a gram-negative and heme-dependent bactreia. H. ducreyi is the responsible of causing chancroid, a sexually transmitted infection forming genital ulcers. Infection with H. ducreyi is associated with an increased risk of acquiring HIV-1 as well as increasing the risk of the HIV-1 transmission. Heme acquisition in H. ducreyi occur through a receptor mediated process in which it start with binding of hemoglobin and heme to their cognate outer membrane receptors, HgbA and TdhA, respectively. The receptors are energized by the TonB complex. Following that the deposition of heme into the periplasmic area is unclear. Profiling of the periplasmic proteome of the H. ducreyi resulted in the identification of a periplasmic- binding protein that highly expressed in heme limitation conditions, and it has been called hHbp. This protein is encoded by a gene resides in a locus of four genes displaying genetic features of an ABC transporter. The gene cluster is organized as an operon comprising an internal membrane protein (IntPro), a sulphate reductase gamma subunit (dsvC), a heme dependant periplasmic bind-ing protein (hHBP), and an ATPase. The purified periplasmic binding protein, hHbp, bind heme in a dose-dependent and saturable manner. Moreover, the binding between heme and hHbp was specifically competitively inhibited by heme. The proposal planned to cre-ate an isogenic hhbp mutant by insertional inactivation using a kanamycin cassette, to genotypically and phenotypically characterize the mutant and thereby to confirm the cru-cial role of the hhbp gene in heme transport in H. ducreyi. Several attempts to ligate a kanamycin resistance cassette into hhbp to construct such a mutant were unsuccessful de-spite the systematic alteration of the ligation conditions and the use of kanamycin re-sistant genes derived from a variety of different plasmids. The explanations for this fail-ure are uncertain. In future work, two other approaches to construct an hhbp mutant in-clude the FRT-FLP recombinase technology and the use of overlapping extension PCR with a chloramphenicol cassette.
18
Jin, Yongji. "Interactive Medical Record Visualization based on Symptom Location in a 2D Human Body." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34255.
Abstract:
An electronic medical record (EMR) is “an electronic record of health-related information on an individual.” EMRs are widely used in healthcare organizations and have many advantages over traditional paper-based medical records, such as their efficiency and reduced storage needs.
However, the use of EMRs has not yet reached its full potential. The numerous items of medical data are always shown with redundant and complex text contained in various monotonous forms and tables. It is hard for users to obtain useful information in a short timeframe.
We propose a prototype system to intuitively and interactively visualize patients’ medical records. Navigation is improved through graphics-based and interaction-based visualization. Our interface features clickable two-dimensional (2D) images of a human body, on which the symptom locations are the starting point of the navigation. In addition, interactive and classified history visualization is also provided. Finally, some pertinent suggestions and comments from medical professionals are discussed.
19
Blais, Mario. "Conscience de soi et langage interne." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34555.
Abstract:
L'introspection est souvent contre-intuitive. Par exemple nous croyons, intuitivement, posséder un Moi mais, en réalité, aucun percept de ce "Moi" n'est possible. De plus, notre capacité à conceptualiser le Moi est tributaire des fonctions langagières. Ce que nous observons après analyse est que la conscience de soi-même, loin d'être innée, se développe progressivement en corrélation avec le développement du langage. Le concept de Soi se développe également ainsi.
Plusieurs auteurs tendent à confirmer ce fait: la capacité de référer du sujet l'amène inconsciemment à prendre conscience de lui-même. L'autoréférence est donc le critère indispensable à l'émergence d'une conscience articulée de soi-même. À l'aide de différents ouvrages consacrés à l'étude de ce domaine, nous proposons une analyse de la présente question.
Le principal objectif de cette thèse est d'étudier de plus près le développement de la conscience de soi à travers une analyse des différents stades de développement chez l'enfant. Nous voulons en évaluer les caractéristiques essentielles et confirmer le rôle prépondérant du langage interne dans la capacité à devenir à la fois conscients de soi-même mais également dans la capacité à se projeter dans l'avenir (maintien du "Soi" ou "Moi" temporel).
Dans la dernière section de thèse nous voulons démontrer, à l'aide d'étude de cas empiriques, que certaines lésions, particulièrement relatives aux fonctions langagières, entraînent inexorablement des répercussions sur la conscience de soi. Ainsi nous confirmons l'hypothèse de départ: la conscience articulée de soi dépend du langage interne.
20
Al-Sadoon, Zaid. "Seismic Retrofitting of Conventional Reinforced Concrete Moment-Resisting Frames Using Buckling Restrained Braces." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34755.
Abstract:
Reinforced concrete frame buildings designed and built prior to the enactment of modern seismic codes of the pre-1970’s era are considered seismically vulnerable, particularly when they are subjected to strong ground motions. It is the objective of this research to develop a new and innovative seismic retrofit technology for seismic upgrading of nonductile or limited ductility reinforced concrete frame buildings involving the implementation of buckling restrained braces. To achieve this objective, combined experimental and analytical research was conducted. The experimental research involved tests of large-scales reinforced concrete frames under slowly applied lateral deformation reversals, and the analytical research involved design and nonlinear analysis of laboratory specimens, as well as design and dynamic inelastic response history analysis of selected prototype buildings in eastern and western Canada. The research project started with a comprehensive review of the building code development in Canada to assess the progression of seismic design requirements over the years, and to select a representative period within which a significant number of engineered buildings were designed and constructed with seismic deficiencies. A similar review of seismic design and detailing provisions of the Canadian Standard Association (CSA) Standard A23.3 on Design of Concrete Structures was also conducted for the same purpose. Six-storey and ten-storey prototype buildings were designed for Ottawa and Vancouver, using the seismic provisions of the 1965 National Building Code of Canada, representative of buildings in eastern and western Canadian. Preliminary static and dynamic linear elastic analyses were performed to assess the effectiveness of upgrading the ten-storey reinforced concrete building designed for Ottawa. The retrofit methods studied consisted of lateral bracing by adding reinforced concrete shear walls, diagonal steel braces, or diagonal steel cable strands. The results indicated that the retrofit techniques are effective in limiting deformations in non-ductile frame elements to
the elastic range. The numerical analyses were used to demonstrate the effectiveness of Buckling Restrained Braces (BRBs) as a retrofit method for seismically deficient reinforced concrete frame buildings. The experimental phase of research consisted of two, 2/3rd scale, single bay and single storey reinforced concrete frames, designed and constructed based on a prototype sixstorey moment resisting frame building located in Ottawa and Vancouver, following the
requirements of the 1965 edition of the NBCC. One test specimen served as a bare
control frame (BCF) that was first tested, repaired and retrofitted (RRF) to evaluate the effectiveness of the proposed retrofit methodology for buildings subjected to
earthquakes in the City of Ottawa. The control frame was assessed to be seismically
deficient. The second frame served as a companion non-damaged frame (RF) that was retrofitted with a similar retrofit concept but for buildings subjected to earthquakes in the City of Vancouver.
A new buckling restrained brace (BRB) was conceived and developed to retrofit existing sub-standard reinforced concrete frames against seismic actions. The new BRB consists of a ductile inner steel core and an outer circular sleeve that encompasses two circular steel sections of different diameters to provide lateral restraint against buckling in compression of inner steel core. Mortar is placed between the two circular sections to provide additional buckling resistance. The inner core is connected to novel end units that allow extension and contraction during tension-compression cycles under seismic loading while providing lateral restraint against buckling within the end zones. The end units constitute an original contribution to the design of Buckling Restrained Braces (BRBs), providing continuous lateral restraint along the core bar. The new technique has
been verified experimentally by testing four BRBs on the two test structures under
simulated seismic loading. The test results of the BRB retrofitted frames indicate
promising seismic performance, with substantial increases in the lateral load and
displacement ductility capacities by factors of up to 3.9 and 2.6, respectively. In addition, the test results demonstrate that the BRB technology can provide excellent drift control, increased stiffness, and significant energy dissipation, while the reinforced concrete frames continue fulfilling their function as gravity load carrying frames. The above development was further verified by an exhaustive analytical study using SAP2000. At the onset, analyses were conducted to calibrate and verify the analytical models. Two-dimensional, one-bay, one-storey models, simulating the BCF and RRF test frames, were created. The models were subjected to incrementally increasing lateral displacement reversals in nonlinear static pushover analyses, and the results were compared with those obtained in the test program. Material nonlinearity was modeled using “Links” to incorporate all lumped linear and nonlinear properties that were defined with moment-rotation properties for flexural frame members and with force-displacement properties for the diagonal buckling restrained braces. Comparison with test data demonstrated good agreement of the frame behaviour in the elastic and post-elastic ranges, and the loading and unloading stiffness. The research program was further augmented with nonlinear dynamic time history analyses to verify the feasibility of the new retrofit technique in multi-storey reinforced concrete frame buildings located in Canada and their performances relative to the performance-based design objectives stated in current codes. Prior to conducting the analyses, 450 artificial earthquake records were studied to select the best matches to the Uniform Hazard Spectra (UHS) according to the 2010 edition of the NBCC for Ottawa and Vancouver. Furthermore, additional analyses were conducted on buildings for the City of Ottawa based on amplified Uniform Hazard Spectrum compatible earthquake records. The nonlinear time-history response analyses were conducted using a model that permits inelasticity in both the frame elements and the BRBs.The results indicated that reinforced concrete buildings built before the 1970’s in the City of Ottawa do not require seismic retrofitting; they remain within the elastic range under current code-compatible earthquake records. The structural building performance is
within the Immediate Occupancy level, and all structural elements have capacities
greater than the force demands. In the City of Vancouver, buildings in their virgin state experienced maximum interstorey drifts of 2.3%, which is within the Collapse Prevention structural performance level. Improved building performance was realized by retrofitting the exterior frames with multiple uses of the BRB developed in this research project. The seismic shear demands were reduced in the columns, while limiting the deformations in the non-ductile frame elements to the elastic range. The lateral interstorey drift was limited to 0.92%, which lies within the Life Safety structural performance level.
21
Kutcher, Stephen Alexander. "Investigating the Influence of NEDD4L in the Development of Salt Sensitive Hypertension with Age." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34955.
Abstract:
Background: Hypertension, a leading risk factor for cardiovascular disease, exhibited in 17.7% of the Canadian population, and attributed to 13% of world mortality, is influenced by both the environment and genetics. Salt sensitivity is described at higher rates in the hypertensive population. The NEDD4-like (NEDD4L) protein is important in sodium reabsorption and has been implicated in essential hypertension and salt sensitivity.
Objectives: Two variations (rs4149601/rs2288774) found in NEDD4L have been associated with salt sensitivity and hypertension; a third (rs576416) is in linkage disequilibrium with rs4149601. The purpose of this study is to assess the relationship between the NEDD4L rs4149601, rs2288774, and rs576416 single nucleotide polymorphisms with sodium and age on blood pressure (BP).
Methods: Canadian hypertensive patients were recruited through the University of Ottawa Heart Institute, with genotyped data from Leuven, Belgium, and the DNA of subjects from Warsaw, Poland also included in the study. Eligible subjects were studied off anti-hypertensive medications. Daytime BP was measured using 24hr ambulatory BP monitoring in 662 Caucasian hypertensives (BP ≥130/85 mmHg). 24hr urine Na+ was collected. DNA from Canada and Poland was genotyped on the GeneTitan Affymetrix Axiom platform and through TaqMan MGB probe-based RT-PCR, while the Belgium samples were analyzed on Illumina 1M-duo arrays. Simple and multivariate linear regression modelling with SAS 9.4.0 was used for genotypic comparisons affecting BP, combined with age and corrected urine sodium.
Results: The three hypertensive populations were significantly different (P<0.05) across all demographic and clinical measures, even when stratified by sex. The Polish and female hypertensives from Canada and Belgium were removed from the analysis for lacking the general populations’ trend of increasing BP with age. Multiple linear regressive modelling found a significant association (Pmodel=0.0034) of rs4149601 GA (P=0.0129) and GG (P=0.0082), with age and urine sodium, on SBP in the Belgium male hypertensives (n=273). No significant models analyzing the association of rs576416 and rs2288774 with BP in the Belgium population were found. In the Canadian hypertensive population (n=120) no association on the discrete analyses of the rs4149601, rs576416, and rs2288774 genotypes were found; however the combination of the GG rs4149601 and AA rs576416 (β=0.021, P=0.03) and the GG rs4149601 and CC rs2288774 (β=0.020, P=0.04) genotypes showed significant associations with BP in borderline significant models (P=0.055 and P=0.094 respectively), when analyzed with urine sodium levels and age.
Conclusions: A significant influence of the rs4149601 G-allele, with urine sodium and age, was found to be associated with an increase in BP in the Belgium males. Multiple linear modelling describing borderline significant findings in the interaction of rs4149601 with rs576416, and rs4149601 with rs2288774 in Canadian male hypertensives suggests of the possible synergism between polymorphisms and development of salt sensitive hypertension. Future research could evaluate the role of NEDD4L on the sex differences in early-onset salt-sensitive hypertension.
22
Travers, James Peregrine. "Studies relating to diabetic pregnancy : effect of hyperglycaemia upon carbohydrate metabolism and insulin on growth in the rat embryo." Thesis, University of Leicester, 1989. http://hdl.handle.net/2381/34255.
Abstract:
Congenital abnormalities are up to four times more frequent in diabetic pregnancy than in the general population. Human and animal studies suggest several factors which may be involved in diabetic embryopathy, one of which is maternal hyperglycaemia. Although most clinical studies have reported on insulin treated diabetic pregnancy, (associated with higher serum insulin levels on average), few suggest that lack of insulin as encountered in poorly controlled or undiagnosed metabolically decompensated diabetic pregnancy may contribute to diabetic embryopathy. The first part of this thesis aims to establish whether rat embryos can metabolise excess glucose, (as encountered in maternal hyperglycaemia). Findings have shown that they are unable to do this and it is postulated that the unmetabolized glucose is free to exert any teratological effects. Enzyme kinetic studies show that glucokinase, (active at high glucose concentrations) is inactive during organogenesis. The role of insulin in rat embryonic growth and development was also assessed by culture of rat embryos in insulin deficient rat serum. This showed that embryonic growth and development was abnormal such serum. Supplementation with insulin, restored the ability of the insulin deficient serum to support normal growth and development. Culture of rat embryos in guinea pig serum known to contain a biologically inactive insulin for rat systems also resulted in abnormal rat embryonic growth and development which was largely restored by the supplementation of such serum with a biologically active insulin. Insulin was not detected by sensitive immunocytochemical methods before 13 days gestation. Thus insulin is required for normal embryonic development, but the earliest appearance of rat embryonic insulin was not until the much later stages of organogenesis. This would suggest that the embryo is dependent upon maternal insulin for normal development during most of organogenesis.
23
Devorak, Nicholas A. "Organizational analysis of energy manpower requirements in the United States navy." Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/34655.
Abstract:
Approved for public release; distribution is unlimitedThe Secretary of the Navy (SECNAV) directed NPS to establish energy-focused subspecialty codes (SSC) that will prepare officers to manage all aspects of energy. In response to this SECNAV directive NPS has developed four energy-focused degree plans in the areas of Operations Analysis, Financial Management, Mechanical and Electrical Engineering. An analysis of the current force structure requirements was necessary to assess and implement a new direction. At the present time, the Navy utilizes petroleum management officers as energy managers. Unfortunately, the Navy Officer Billet Classification (NOBC) Codes assigned to these officers do not translate into the identification of the billets being identified with the energy SSCs. Analysis shows a possible solution to this issue is to establish afloat and ashore general Energy NOBCs that could be assigned as either a primary or secondary NOBC Energy billets. Specifically, analysis shows the majority of NOBCs assigned to energy billets are from the Naval Operations (90009999) Field. Therefore, this research recommends the establishment of two Energy NOBCs to support future Fleet Energy Management Challenges.
24
Umar, Aminu Mohammed. "Nigeria and the Boko Haram sect: adopting a better strategy for resolving the crisis." Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/34755.
Abstract:
Approved for public release; distribution is unlimitedThe purpose of this thesis is to examine the growth and activities of the Boko Haram sect in Nigeria with the aim of suggesting a strategy for resolving the crisis. The thesis will focus on the evolution of the sect and the enabling environment that served to support its growth especially in the North East region of Borno, Yobe, and Adamawa States of Nigeria. This thesis will demonstrate that the present response of the government which is more focused on addressing the symptoms of terrorism, remains inadequate, and requires a strategy that addresses the root cause and symptoms of terrorism to resolve the crisis. Such a strategy involves a government-wide approach whereby the military expands its operations to limit the operating space for the sect, and the government simultaneously addresses the root causes of the crisis as well as the conditions that facilitated the growth of Boko Haram in North-Eastern Nigeria.
25
McMillan, Brian L. "A proposed guide for improving the organization and conduct of Procurement Management Review within the Marine Corps Field Contracting System." Thesis, Monterey, California: Naval Postgraduate School, 1990. http://hdl.handle.net/10945/34855.
Abstract:
Approved for public release; distribution is unlimited.This thesis analyzes the organization and conduct of the Procurement Management Review (PMR) program within the Marine Corps Field Contracting System. An attempt is made to identify, to the maximum extent possible, the goals, management philosophy, organization, and methods considered to be ideal for PMR by three sources: literature, previous studies, and contracting professionals. An analysis and comparison between this consensus and HQMC's current PMR policies and procedures, as well as field contracting personnel's perceptions of these policies and procedures is conducted to highlight similarities and differences, and to provide acquisition managers at HQMC with alternatives for improving current practices to optimize the effectiveness of the PMR program, given the Marine Corps Field Contracting System's peculiar acquisition needs and structure.
26
Neil, David Langley. "Allelic variation and mutation at human hypervariable minisatellite loci." Thesis, University of Leicester, 1994. http://hdl.handle.net/2381/34455.
Abstract:
Human polymorphic tandemly repeated loci have been exploited in linkage analysis and have also had a profound impact on forensic and legal medicine. Most DNA typing systems assay allelic length variation at tandem repetitive loci such as minisatellites. Although these include the most informative loci in the human genome, their forensic application is limited by innaccuracies in allele length measurement, and the need to make population genetic assumptions in statistical analysis. Minisatellite alleles frequently vary not only in repeat copy number, but also in the interspersion pattern of variant repeat units, which can be assayed by minisatellite variant repeat mapping (MVR). This technique uses either restriction analysis, or more efficiently MVR-PCR, to display minisatellite allele internal structures as digital codes that can theoretically distinguish millions of alleles. MVR-PCR profiles from the hypervariable minisatellites MS31A and MS32 generate extraordinarily heterogenous codes, reflecting extreme levels of allelic variability, far in excess of that detectable by allele length analysis. These codes are appropriate for forensic investigations and for analysing allelic diversity and mutation. Comparison of MVR structures showed that most alleles at both loci were different, implying the existence of many thousands of alleles worldwide. Variation between groups of alleles with related MVR-structures was largely confined to one end of the locus, providing evidence for a localised mutation "hotspot". This was confirmed by using MVR-PCR to characterise de novo mutation events at both loci. Most mutations involved gains of small numbers of repeats at the ultravariable end of the tandem repeat array, by highly polar intra- and interallelic unequal conversion-like processes. Evidence suggested that this mechanism was male germline-specific, and possibly meiotic. Less frequent intraallelic deletions were seen in male and female germline and in somatic tissues. These observations suggest that the same mechanisms of repeat unit turnover may operate at different hypervariable minisatellites.
27
Yarlett, Robert Thomas. "Quantifying the role of parrotfish in the production and cycling of carbonate in coral reef ecosystems." Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/34655.
Abstract:
Parrotfish are a diverse and ubiquitous group found on coral reefs worldwide. They are categorised into three main feeding modes; the browsers, scrapers and excavators, which together perform a number of important functional roles on coral reefs. Scraper and excavator parrotfish are common on most Indo-Pacific coral reefs where their roles in bioerosion, sediment production, grazing pressure and sediment reworking have been shown to influence benthic community composition, reef growth potential and sediment supply to reef habitats and reef associated sedimentary landforms. However, despite the widely known importance of parrotfish on coral reefs, our understanding of how their roles in carbonate cycling vary among species and among whole parrotfish communities in different reef habitats remains limited. This thesis produces original contributions to knowledge in the areas of species specific bioerosion estimates for the central Indian Ocean, bottom-up controls of habitat type on parrotfish assemblages and how variations in parrotfish assemblages translate to contributions to carbonate cycling processes among different reef habitats. The study was carried out across eight habitats on an atoll-edge reef platform in the central Maldives, where it was found that parrotfish community composition was driven by reef structural complexity and substrate type. Parrotfish occurred in six of the eight habitats, comprising ~44% of the platform area. Among these habitats, overall grazing pressure, bioerosion rates, sediment reworking and sediment production varied markedly. These processes were also found to have different spatial patterns over the reef platform, showing that they are not necessarily tightly coupled. In addition, reef habitats can vary in their importance for both sediment supply, and the relative importance of reworked sediment. Parrotfish produced a wide range of sediment size fractions, from < 32 to 2000 μm and produced predominantly coral sands (>80%) between 125 and 1000 μm in diameter. This is comparable to the grain types found on local reef islands, and it is likely that the most significant supply of this material is from habitats on the atoll-edge side of the platform (which make up ~20% of the total platform area). Quantifying parrotfish functional roles and understanding the drivers behind these processes is important for informing future empirical and modelling studies, particularly as coral reefs undergo a time of dramatic environmental change.
28
Alkhalifa, Saad Fadhil Ramadhan. "2D materials for magnetic and optoelectronic sensing applications." Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/34955.
Abstract:
In the last decade, the emerging classes of two-dimensional (2D) materials have been studied as potential candidates for various sensing technologies, including magnetic and optoelectronic detectors. Within the quickly growing portfolio of 2D materials, graphene and semiconducting transition metal dichalcogenides (TMDs) have emerged as attractive candidates for various sensor applications because of their unique properties such as extreme thickness, excellent electrical and optical properties. In this thesis, I have exploited the unique properties of graphene and TMDs materials to develop 2D detectors based on field effect transistors for sensing magnetic field and light. In the first part of this thesis I have shown how the sensitivity of the properties of 2D materials to their surrounding environment can be turned into a feature useful to create new types of magnetic field sensors. The first experimental demonstration of this concept involved the use of graphene deposited on hexagonal Boron Nitride (h-BN), where the inevitable contaminations occurring at the interface of the two materials was used to generate a large magnetoresistance (MR) for a magnetic field sensor. Specifically, I have demonstrated that the contaminations generate an inhomogeneity in the carrier mobility throughout the channel, which is a required ingredient for magnetic field sensing based on linear magnetoresistance (LMR). Another approach I used to make a LMR sensor was by exploiting the large dependence of the mobility in graphene on the Fermi level position. This concept was used to generate two parallel electron gases with different mobility by tuning the Fermi level with an electrical field employing a field effect transistor. The second part of the thesis is focussed on strategies to reduce the impact of the surrounding environment on the properties of 2D materials in order to improve their performance. In particular, I used a 2D heterostructure encapsulated in an ionic polymer to makeii a highly responsive graphene-TMD photodetector. In this device, the ionic polymer covering the heterostructure was employed to screen the long-lived charge traps that limit the speed of such detectors, resulting in a drastic improvement of the detector responsivity properties. Finally, some of the 2D materials properties are very sensitive to the configuration of the electronics measurement setup. For example, effects behind spintronic and valleytronic concepts require non-local electrical transport measurement. We built a novel circuit that enables the detection of such effects without concern about the spurious contributions.
29
Robbins, Jennifer L. "The role of mismatch repair in mediating cellular sensitivity to cisplatin : the Escherichia coli methyl-directed repair paradigm." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34155.
Abstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Biological Engineering Division, 2006.Includes bibliographical references (v. 2, leaves 195-258).
The anticancer drug cisplatin is in widespread use but its mechanism of action is only poorly understood. Moreover, human cancers acquire resistance to the drug, which limits its clinical utility. A paradox in the field is how loss of mismatch DNA repair leads to clinical resistance to this widely used drug. The phenomenon of cisplatin tolerance in mismatch repair deficient cells was initially discovered in E. coli, where methylation deficient dam mutants show high sensitivity to cisplatin and dam mutants with an additional mutation in either of the mismatch repair genes mutS or mutL show near wildtype levels of resistance. A prevalent explanation for this observation is the abortive repair model, which proposes that in dam mutants, where the strand discrimination signal is lost, mismatch repair attempts futile cycles of repair opposite cisplatin-DNA adducts. Previous findings have supported this model to the extent that MutS, the E. coli mismatch recognition protein, specifically recognizes DNA modified with cisplatin. However it has recently been shown that MutS binding to cisplatin adducts may contribute to toxicity by instead preventing the recombinational repair of a cisplatin-modified substrate, and we have previously shown that recombination is an essential mechanism for tolerating cisplatin damage.
(cont.) In the present study, we examined the global transcriptional responses of wildtype, dam, dam mutS, and mutS mutant E. coli after treatment with a toxic dose of cisplatin. We also determined any dose-response at the transcriptional level of several SOS response genes and other genes involved in DNA repair by real time RT-PCR. Furthermore, we performed single-cell electrophoresis in order to determine the effect of mismatch repair on the level of double-strand break formation in cisplatin-treated cells. Our results show that Dam-deficient strains exhibit unique gene regulation that may be due to mismatch-repair induced DNA damage in the absence of adenine methylation. In addition, cisplatin treatment induces double-strand break formation and the SOS response in a dose-dependent manner, and both break formation and the SOS response are greatest in the hypersensitive dam mutant strain. The higher level of cisplatin-induced double-strand breaks in the dam mutant may be dependent on functional mismatch repair.
by Jennifer L. Robbins.
Ph.D.
30
Soontrapa, Chaiyod. "Design optimization and analysis of coated particle fuel using advanced fuel performance modeling techniques." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34455.
Abstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2005.Includes bibliographical references (p. 154).
Modifying material properties provides another approach to optimize coated particle fuel used in pebble bed reactors. In this study, the MIT fuel performance model (TIMCOAT) was applied after benchmarking against the experiment results. The optimization study focuses on the fracture toughness of silicon carbide and Bacon anisotropy factor (BAF) of pyrocarbon. The variations on the silicon carbide toughness show that higher fracture toughness leads to a lower fuel failure probability, as expected. However, the results from the BAF variations reveal that a higher BAF lowers a fuel failure probability. This quite contradicts the generally believed notion that a higher BAF would increase fuel failures. In addition to the fuel design optimization, the failure characteristics of coated particle fuel are explained and the key factors influencing such characteristics are identified.
by Chaiyod Soontrapa.
S.M.
31
Chan, Kai Pak. "Stochasticity induced by electrostatic waves in magnetized plasma." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/34055.
Abstract:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994, and Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1994.Includes bibliographical references (leaves 105-106).
by Kai Pak Chan.
B.S.
M.Eng.
32
Hall, Ralph P. 1975. "Understanding and applying the concept of sustainable development to transportation planning and decision-making in the U.S." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34555.
Abstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology, Management, and Policy Program, 2006.Includes bibliographical references.
This research demonstrates that sustainable development is a multidimensional concept that should be approached in a transdisciplinary manner. Its objective has been to synthesize and integrate disparate and currently unconnected lines of thought that have not yet been applied in a systematic way to promote sustainable development and sustainable transportation. The primary contribution of this research is the theoretical development of a decision-support framework that identifies the tools and approaches that decision-makers could/should use to create policies and programs that transition society towards sustainability. These tools and approaches are either articulated or developed by the author throughout the dissertation. Specific ideas explored include a Rawlsian/utilitarian decision-making philosophy; a hybrid trade-off/positional analysis framework that is presented as an alternative to benefit-cost analysis; ecological vs. environmental economics; participatory backcasting; and ways to stimulate disrupting and/or radical technological innovation. To identify gaps that exist between theory and practice, the approach embodied in the proposed sustainable transportation decision-support framework is compared with current metropolitan transportation planning and decision-making processes in the U.S. The framework is then used to consider how the U.S. federal government might move the nation's transportation system towards sustainability.
by Ralph P. Hall.
Ph.D.
33
Afergan, Michael Moïse. "Applying the repeated game framework to multiparty networked applications." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34655.
Abstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 145-154).
This thesis presents repeated game analysis as an important and practical tool for networked application and protocol designers. Incentives are a potential concern for a large number of networked applications. Well-studied examples include routing and peer-to-peer networks. To the extent that incentives significantly impact the outcome of a system, system designers require tools and frameworks to better understand how their design decisions impact these incentive concerns. Repetition is a prevalent and critical aspect of many networking applications and protocols. Most networked protocols and architectures seek to optimize performance over a longer timescale and many have explicit support for repetition. Similarly, most players in networked applications are interested in longer horizons, whether they be firms building a business or typical individuals trying to use a system. Fortunately, the study of repeated interaction between multiple self-interested parties, repeated games, is a well-understood and developed area of economic and game theoretic research. A key conclusion from that literature is that the outcome of the repeated game can differ qualitatively from that of the one-shot game. Nonetheless, the tools of repeated games have rarely if ever been brought to bear on networking problems. Our work presents the descriptive and prescriptive power of repeated game analysis by making specific contributions to several relevant networking problems.
(cont.) The applications considered are inherently repeated in practice, yet our research is the first to consider the repeated model for each particular problem. In the case of interdomain routing, we first show that user-directed routing (e.g., overlays) transforms routing into a meaningfully repeated game. This motivates us to consider protocols that integrate incentives into routing systems. In designing such a routing protocol, we again use repeated games to identify important properties including the protocol period and the format of certain protocol fields. Leveraging this insight, we show how it is possible to address the problem of the repeated dynamic and arrive at a more desirable outcome. In the case of multicast overlay networks, we show how repeated games can be used to explain the paradox of cooperative user behavior. In contrast to prior models, our repeated model explains the scaling properties of these networks in an endogenous fashion. This enables meaningful examination of the impact architecture and protocol design decisions have on the system outcome. We therefore use this model, with simulation, to descry system parameters and properties important in building robust networks. These examples demonstrate the important and practical insights that repeated game analysis can yield. Further, we argue that the results obtained in the particular problems stem from properties fundamental to networked applications - and their natural relationship with properties of repeated games.
(cont.) This strongly suggests that the tools and techniques of this research can be applied more generally. Indeed, we hope that these results represent the beginning of an increased use of repeated games for the study and design of networked applications.
by Michael Moïse Afergan.
Ph.D.
34
Yang, Joel K. (Joel Kwang wei). "Fabrication of superconducting nanowire single proton detectors." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34355.
Abstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Includes bibliographical references (p. 81-85).
The future NASA Mars project will need an ultra-fast, highly sensitive photodetector to increase the bandwidth of free-space long-range communication, which is now done primarily using RF signals. Our original motivation in fabricating superconducting nanowire single-photon detectors (SN-SPD) is to fulfill this need. The SN-SPD's reported GHz counting rates [1] make it very attractive for this application. A new fabrication process for making SN-SPDs using hydrogen-silsesqioxane (HSQ), a high-resolution electron-beam lithography resist will be presented. An electron-beam proximity-effect correction program was developed to achieve nanowires with uniform linewidths, which is important for device performance. Finally, we present initial test results that show device functionality and performance. Our best device has a detection efficiency of [approx.] 10 % at 1064 nm photon wavelength at 2.1 K and a photon-induced voltage-pulse duration of [approx.] 3 ns.
by Joel K. Yang.
S.M.
35
Murdoch, Kimberly R. "Development of a robust work transfer iomplementation process." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/34755.
Abstract:
Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics; in conjunction with the Leaders for Manufacturing Program at MIT, 2004.Includes bibliographical references (p. 121-122).
The industry-wide need for a robust method of transferring the manufacturing of a component from one location to another is addressed in this thesis. Work transfer activities can be initiated due to a number of business reasons. These reasons include: reducing general operating costs, increasing asset utilization, and reducing overhead costs by leveraging manufacturing synergies. However, in order to fully realize the benefits of a work transfer activity, a robust work transfer process is needed to mitigate the risks associated with work transfer activities. In this thesis, the work transfer process is studied with specific concentration on the implementation phase of the work transfer. The overall objective is to propose and document a robust work transfer implementation process that improves the reliability with which work transfers are executed. The current work transfer process at The Boeing Company, in addition to the strategic and business decisions that initiate work transfers and the selection of manufacturing processes and technologies, serve as the starting point of the work and associated considerations. In developing this recommended work transfer process, robustness was addressed as the risks associated with the implementation of work transfer activities and subsequent risk mitigation activities were identified, in cooperation with key stakeholders, via a failure modes and effects analysis (FMEA). These risk mitigation activities were then integrated into the current work transfer process, and the resulting overall process was documented. This recommended process was then assessed by comparing it with the current work transfer process on the basis of time and cost. The results of this assessment
indicate that the recommended work transfer is an improvement over the current work transfer process. The recommended process is presented generically, and as such is flexible due to its adaptability to individual situations. When implementing the recommended work transfer process, it is suggested that the responsibility for and authority of the work transfer process be assigned to an individual to ensure adherence to and adoption of the process. System-level interactions of factors within a manufacturing system are also investigated and presented in this thesis. The results of this investigation illustrate the need to consider the potential long-term system-level results when making business decisions. Finally, the issue of manufacturing flexibility is discussed, and the consideration of manufacturing mobility during the design of manufacturing processes is suggested.
y Kimberly Robyn Murdoch.
S.M.
M.B.A.
36
Kaya, Ömür Sedat. "Evaluation and improvement of proactive customer notification in e-commerce environment." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/34855.
Abstract:
Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; in conjunction with the Leaders for Manufacturing Program at MIT, 2005.Includes bibliographical references (p. 53).
The Internet, and thus e-commerce, both Business to Consumer (B2C) and Business to Business (B2B), has changed the way companies do business with each other and communicate with their customers. Because of the speed of the Internet, information transfer both among companies and between a company and its customers has become faster, albeit technologically more complex, in the e-commerce era. It has been a challenge for e-companies to develop creative, satisfying ways of communicating with their customers. After all, the Internet is approximately a decade old, and there has not been enough accumulation of knowledge about customer behavior. Unlike in conventional shopping where the customer takes the product with him/her or makes specific delivery arrangements in a specific geographical zone, in e-commerce the customer picks a specific delivery method from literally anywhere in the world at any time. This, of course, brings many logistical challenges for a successful delivery. Dell Computer Corporation, famous for its build-to-order and direct model, is one of the biggest e-commerce companies in the world and, thus, faces the challenges that any e- commerce company must confront, such as communicating with customers efficiently in a timely manner. Therefore, such logistical challenges that the e-commerce era has brought are not unique to Dell. One such challenge is effective communication with the customer after a shipment is just processed. This thesis focuses on finding best-of-breed technologies and applications in the proactive customer notification field through benchmarking.
(cont.) This thesis also offers a tool to evaluate various technology providers and to make decisions based on the analysis.
by Ömür Sedat Kaya.
S.M.
M.B.A.
37
Fraser, Sydney Gordon. "Cognitive and behavioural strategies in the management of suicidal behaviour." Thesis, University of Leicester, 1987. http://hdl.handle.net/2381/34655.
Abstract:
Study One of this research aimed to assess interpersonal problem-solving ability in individuals who evidenced suicidal behaviour. Suicide attempters were compared with mixed psychiatric outpatients and normal controls on a measure of means-ends problem-solving. The results of Study One suggested that suicidal individuals produced significantly fewer relevant means, story directed responses and sufficient narratives compared to both normal and psychiatric subjects. On qualitative indices of introspection, emotional relevant means and on time and obstacle recognition suicidals were significantly more deficient than control groups. Amongst suicidal subjects greater social dysfunction, stress and affective disturbance was associated with poorer interpersonal problem-solving. A model for the development of suicidal behaviour which suggested possible points of entry for intervention was proposed. In Study Two three treatment strategies for suicidal behaviour - Cognitive Therapy, Problem-solving Training and Psychiatric After Care were compared. In general the results suggested that all treatments were having some positive effects. The most significant changes in problem-solving skills occurred in the group receiving such training but improvement in this area was also noted in the Cognitive Therapy Group. It was proposed that aspects of Cognitive Therapy may have direct influence on problem-solving behaviour. Affective change seen at the end of eight weeks of treatment followed a different time course compared to cognitive change and the maintenance of such change to follow-up was shown to be dependent upon skills learnt during Cognitive Therapy and Problem-solving Training. Problem-solving Training had the most significant impact in improving social dysfunction and all treatments were shown to reduce suicidal ideation but at differing rates. One episode of suicide attempt occurred in the Psychiatric After Care Group representing a 6.25 percent rate of reoccurrence. It was concluded that the acquisition of interpersonal and cognitive skills held implications for the prophylaxis of suicidal behaviour. Suggestions for early primary intervention within the family and education systems were proposed.
38
Clarke, Michael P. "Silylenes as intermediates in the 'direct synthesis'." Thesis, University of Leicester, 1989. http://hdl.handle.net/2381/34055.
Abstract:
Butadiene trapping experiments demonstrated that the silylenoids, :SiMeCl and :SiC12, are intermediates in the Direct Synthesis. It is believed that two types of silylenoid are formed on the metal surface. One type reacts on the surface with methyl chloride to generate methylchlorosilanes. The second type is released from the surface where as the free silylene it may be trapped by butadiene; it is not important in methylchlorosilane production. The gas phase reaction between the silylenes, :SiMeX (X=Me,Cl) and :SiCl2, and halomethanes involves two parallel series of reactions: silylene insertion reactions and radical chain reactions. In the reaction between :SiMe2 ch1orofluorocarbons (CFCs) an efficient chain sequence dominated; the driving force being the formation of Si-Cl bonds. The radical chain initiation step is believed to involve the dissociation of a singlet silylene-CFC acceptor complex bound through chlorine to produce haloalkyl (major chain carrier) and ClMe2Si. radicals. Fluorine was never abstracted. The major cyclic adduct produced when :SiMeX (X=H,C1,Me) is trapped by butadiene, is the result of a 1,3-silyl shift in the initial vinylsilacyclopropane, not Si-C bond rupture. Silacyclopropanes containing a Si-H bond undergo a rapid reversible ring-opening 1,2-H shift generating an alkylsilylene. Thermolysis of 1,1-dimethylsilacyclopent-3-ene produced 1,1-dimethylsilacyclopent-2-ene, butadiene, and :SiMe2 via a non-concerted mechanism involving a vinylsilacyclopropane intermediate. Computer modelling demonstrated that no single reaction is rate-determining with all intermediates in a steady-state. Alkene elimination from 1-allyl-1-silacyclopent-3-enes involves a conformationally enhanced endocyclic retro-ene reaction generating a 2H-silole, followed by a fast 1,5-H shift giving a 1H-silole. When the allyl group is substituted, it isomerises via a 1,3-silyl shift. a-Aryl-chloromethylsilanes, ArMeXSiCH2Cl (X=H,Me), underwent isomerisation in the gas phase as a result of H?C1 exchange when X=H, and Ar?Cl exchange when X=Me. H?Cl exchange is believed to involve an 'inverse ylide', whereas Ar?Cl exchange is believed to be concerted, i.e. a dyotropic rearrangement.
39
Arrieta-Martinez, Melania. "Biochemical and rheological properties of waxy wheat flour dough." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/34455.
Abstract:
Master of ScienceDepartment of Grain Science and Industry
Yong-Cheng Shi
Jon Faubion
The rheological properties of two waxy and two normal wheat flours were investigated and the observed differences between them were explained by biochemical analysis. Protein analysis showed that waxy flour had lower polymeric to monomeric ratio (0.70 and 0.58 for waxy flour compared to 0.75 and 0.76 for normal flour) and higher gliadin content in waxy wheat dough (43.9 and 47.3 for waxy wheat dough compared to 41.0 and 41.7 for normal wheat dough). Waxy flour had high amounts of insoluble (IPP) and unextractable (UPP) polymeric protein despite the poor dough forming properties of the waxy flours, contrary to previous correlations made between IPP, UPP and dough strength. Gluten index determination showed a clear difference between waxy and normal flour; there was no gluten aggregation when the waxy samples were tested. The determination of gluten index done on a variety of water washed flour samples indicated that the water-extractable fraction may contain compounds that affect gluten aggregation. HPLC analysis coupled with arabinose/xylose ratio and viscosity determination of the water extractable portion of the flour indicated that water extractable arabinoxylans (WEAX) in waxy wheat flour were different in composition and conformation. Further research is needed to determine if they could be responsible for the lack of gluten aggregation in waxy flour.
40
Abdelkarim, Nazar B. H. "Numerical modelling of direct-injection gasoline fuel sprays." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/34055.
Abstract:
This thesis presents a numerical study of the break-up and atomisation of gasoline fuel sprays injected into atmospheric flow conditions and environments related to combustion chamber conditions. Calculations of the fuel break-up process were achieved by four different models: Taylor Analogy Break-up (TAB), the wave instability theory (WAVE), the Hybrid Sheet-TAB and the Hybrid WAVE-FIPA models. The TAB model relates the break-up process to the droplet oscillations; whereas the WAVE models calculate the fuel break-up from the unstable waves on the droplet surface. The modified version of the TAB model, called the Hybrid Sheet-TAB model delays the start of the break-up further downstream from the nozzle tip. A new hybrid model, the WAVE-FIPA model, divides the spray atomisation processes into a primary stage, where the WAVE model is used, and a secondary stage, which is simulated using experimental correlations to calculate the break-up time for the low Weber number droplets.
41
Müller, Alexandre Pastoris. "Sistema insulina/fator de crescimento semelhante à insulina 1 (insulina/IGF-1) em hipocampo de roedores : efeitos da interação com exercício físico, dieta hiperpalatável e envelhecimento." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/34655.
Abstract:
Insulina e o fator de crescimento semelhante à insulina-1 (IGF-1) afetam positivamente as funções cerebrais. O exercício físico é um mediador de adaptações do SNC, enquanto o envelhecimento pode ser considerado um fator de risco para o desenvolvimento de doenças neurodegenerativas. Neste trabalho investigamos o efeito do exercício físico, dieta hiperpalatável e envelhecimento no sistema insulina/IGF-1 em hipocampo de roedores. No trabalho onde utilizamos uma dieta hiperpalatavel, para mimetizar o estilo de vida ocidental, causou uma diminuição na passagem de IGF-1 pela barreira sangue cérebro devido ao aumento nos níveis de triglicerídeos séricos. Os trabalhos onde utilizamos camundongos/ratos envelhecidos para verificar os efeitos do sistema insulina/IGF-1no SNC mostraram que, apesar de ocorrer uma compensação do cérebro em aumentar o transporte de IGF-1 pela barreira sangue cérebro e aumento dos receptores em hipocampo, ocorreu uma diminuição da sinalização pós-receptor, assim como perda da melhora cognitiva induzida pela insulina em animais jovens que induziu a produção de fatores tróficos. Nossos resultados apontam que exercício físico aumenta a sensibilidade à insulina no hipocampo por aumentar a translocação e ativação do receptor de insulina e ativação nas proteínas intracelulares. Os resultados apontam para um efeito antioxidante da insulina em preparações de sinaptossoma de ratos quando estimulamos a respiração mitocondrial com succinato. Estes resultados demonstram que fatores ambientais afetam profundamente a ação de hormônios responsáveis pela manutenção da homeostasia cerebral.Insulin and insulin like growth factor-1 (IGF-1) affect the brain function. Physical exercise is proposed as a neurotrophic factor, while aging is considered a key factor to neurodisease. In our work we analyze the effect of physical exercise, high palatable diet and aging in insulin/IGF-1 system in hippocampus of the mice. High palatable diet decreased the transport of IGF-1 in blood brain barrier (BBB) by increased in the serum levels of triglycerides. Aged mice/rats had decrease in insulin/IGF-1 system in brain. Aged mice try to compensate this impair in IGF-1 signaling by increase the transport of hIGF-1 in BBB and increased the levels of IGF-1 receptor in hippocampus, however the intracellular signaling were decreased in aged mice. Aged rats showed resistance to benefits effect of insulin in cognition. Physical exercise increases the insulin sensitivity in hippocampus by increase the translocation and activation of intracellular proteins. Moreover insulin showed an antioxidant effect in synaptossome of the rats. Our results pointing to environmental factors modulated the insulin/IGF-1 system and affect the brain function.
42
Joseph, Eloi. "L'appréhension du territoire penal par le Canada et la France." Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/34655.
Abstract:
Dans un contexte d’internationalisation de plus en plus fort du droit pénal, dû à l’augmentation des coopérations interétatiques face à l’accroissement de la criminalité transfrontalière, la question du territoire est actuelle. Cet espace que chaque Etat s’approprie pour y faire respecter sa conception de l’ordre public peut faire l’objet de revendications par plusieurs pays. Cette étude a pour objectif d’analyser l’appréhension qui est faite du territoire pénal par les ordonnancements juridiques canadien et français. Ce thème de recherche n’a jamais été approfondi spécifiquement en droit pénal ; il est très vaste. Il soulève de nombreuses questions tant sur l’aspect substantiel que procédural du droit pénal. Nous aborderons le territoire pénal des autorités de police dans la recherche des preuves des infractions, celui des magistrats de l’enquête pénale et enfin le territoire des juridictions criminelles. De nombreuses questions pourraient être soulevées en sus ; cependant, étant limité en terme de volume pour le mémoire, une approche plus englobante sera faite lors de la réalisation d’une prochaine thèse. En outre, les Etats peuvent chercher à s’immiscer dans les territoires pénaux étrangers. Cela atteint la souveraineté étrangère et affiche une méfiance envers les autres systèmes répressifs. Les législateurs nationaux, appuyés par la jurisprudence, montrent souvent une volonté de déployer le joug de leurs lois pénales de façon unilatérale. Bien qu’un ensemble de conventions internationales, ou régionales comme dans l’Union européenne, viennent poser la genèse d’une harmonisation des législations, de nombreux conflits de compétence restent encore présents et les solutions apportées ne sont pas toujours adéquates. La comparaison des deux systèmes juridiques permettra de faire ressortir leurs points de convergence et ceux de divergence afin d’avancer dans un travail de conceptualisation du territoire pénal.
43
Plamondon, Mathieu. "La perception du rythme chez les personnes bègues." Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/34055.
Abstract:
Cette étude s’inscrit dans le courant de la psychologie de la perception du temps et du rythme et évalue le lien entre un trouble de la parole, nommément le bégaiement, et la capacité à percevoir et maintenir un rythme régulier. Les performances d’un groupe d’adultes bègues (n = 21) sont comparées à celles d’un groupe d’adultes non bègues (n = 24) lors d’activités de comptage explicite. Les séances comportent trois intervalles temporels standards (800 ms, 1200 ms et 1600 ms) et trois conditions expérimentales (compter silencieusement, compter oralement et compter oralement avec un auxiliaire chargé de l’enregistrement). Les résultats relatifs à la variabilité temporelle révèlent que les participants sont moins bons (ratio de Weber plus élevé) lorsqu’ils comptent silencieusement et lorsqu’ils doivent composer avec des intervalles très longs (1600 ms). L’effet principal de groupe n’est pas significatif, mais l’interaction entre la condition expérimentale, l’intervalle de temps et le groupe s’avère significative. Les adultes bègues ont de moins bonnes performances que les adultes non bègues dans la condition silencieuse avec les intervalles temporels longs (1600 ms). Ceci signale peut-être une limite du traitement de l’information temporelle plus importante chez les personnes bègues lors du traitement de longs intervalles temporels. Enfin, l’étude s’avère également d’intérêt sous l’angle clinique. Les adultes bègues obtiennent un score d’anxiété situationnelle significativement plus élevé que les adultes non bègues. Ce résultat est cohérent avec ce qui est rapporté dans la littérature scientifique et reflète le niveau élevé d’anxiété ressentie par les adultes bègues.This study assesses the effect of a speech disorder, namely stuttering, on the ability to maintain a steady rhythm. The performance of a group of adult stutterers (n = 21) is compared to that of a group of adult non-stutterers (n = 24) during explicit counting activities. There are three counting paces (every 800 ms, 1200 ms or 1600 ms) and three experimental conditions (count silently, count orally and count orally in the presence of an assistant). The results for temporal variability show lower performance (higher Weber ratio) when participants count silently and when they have to deal with very long intervals (1600 ms). There is no main effect of group, but the interaction between the experimental condition, the counting pace and the group is significant. Adult non-stutterers are better than adult stutterers in the silent and long time-interval condition (1600 ms). This finding could be interpreted as an indication of a greater limitation in memory for temporal information in people who stutter. Finally, the experiment shows that adult stutterers have a significantly higher situational anxiety score than adult non-stutterers. This result is consistent with the scientific literature indicating the high level of anxiety experienced by people who stutter.
44
Sirpatil, Brijesh. "Software Synthesis of SystemC Models." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34255.
Abstract:
Technological advances are providing us with the capability to integrate more and more functionality into a single chip. This is leading to a new design paradigm, System On a Chip (SOC). In SOC designs all the functionality of a system is put inside a single chip, leading to increased performance, reduced power consumption, lower costs, and reduced size. SOC design brings with it new challenges and difficulties, however. The designs are now large, complicated and involve both software and hardware components. The designs have to be modeled at a high level of abstraction before partitioning into hardware and software components for final implementation.
SystemC is a system level modeling language useful for System On a Chip design. It provides various features to perform system level modeling and simulation, which are missing in the generic HDL's such as VHDL and Verilog. The hardware portion of the SystemC models can be synthesized into hardware using commercial tools . The software portion can be rewritten as embedded software for the target processor.
The aim of this thesis is to explore the SOC design process and to define methods for software synthesis of SystemC models. Software synthesis involves translation of SystemC models into code that is suitable for execution on an embedded processor. A simple scheduler that replaces the SystemC simulation kernel is proposed. This scheduler allows SystemC models to be executed directly as embedded software without the need for extensive modification or translation. Application of this process to the development of a GSM speech processing system, including the translation of part of the SystemC model into software that will execute on an embedded processor, is shown and the results are presented.Master of Science
45
Mishra, Sanjiv. "An Ex-Ante Economic Impact Assessment of Bt Eggplant in Bangladesh, the Philippines and India." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/34955.
Abstract:
This study projects the economic impact of adoption of Bt eggplant in India, Bangladesh
and Philippines. The welfare benefits from adoption of Bt eggplant are projected to be positive in all three countries. The welfare gains from adoption (discounted at 5 percent) are projected to be US $ 411 million for India, US $ 37 million for Bangladesh and US$ 28 million for the Philippines. Consumers gain about 57% of the welfare benefits, while the
producers gain 43% of the total surplus.
Simulation results indicate that India is in a
position to make significant investments in the development and diffusion of the Bt eggplant
technology, while the Philippines and Bangladesh are likely to benefit from the transfer and adoption of technology from India.The simulations assumed a low seed premium, which would help in increasing the rate of adoption of the technology by the farmers. The findings suggest that potential economic benefits from Bt eggplant are high and efforts should be continued to develop and integrate the Bt eggplant with other IPM practices for effective pest management.Master of Science
46
Tedesco, Patricia. "Interplay: Studies in Rowhouse Design." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34355.
Abstract:
This thesis began as an exploration of the idea of home, a study that revealed the importance of place. Seeking to understand what makes a successful place, I studied neighborhoods with which I was familiar, identifying characteristics of both the vital and the lifeless. As a foundation for architectural exploration, this study helped me to recognize the dynamic qualities of denser, more urban neighborhoods, and to establish rowhousing as the vehicle through which to undertake my exploration of urban living. While providing the genesis for the project and further defining certain elements as worthy of further study, this initial exploration was nonetheless lacking. I had to do more than just speak of the conditions I hoped to achieve and of the characteristics of the elements with which to make the conditions manifest. I had to make the conditions, make the elements. It was essential for me to establish a clear order, so that these conditions could be brought together to form a cohesive whole.
I was able to arrive at a fully conceived expression of the project by structuring the conditions that I identified through the application of three dimensional grids. The interrelationships among the grids helped structure the relationships among various conditions, ensuring that they enhanced one another, and were, in fact, stronger together than separately. Working with the grids taught me that in order for them to be effective regulators the grids had to be intelligible while still being flexible; that they should help define but never dictate. It exposed the tension between the regulating devices we, as architects, utilize as tools for design and the three-dimensional material with which the designs are constructed, as well as the obligation of reconciling the two. Not only must the device accommodate the material and the material reveal the device, but indeed all facets of the design must be considered in relation to one another and to the whole. When philosopy, device, and material work in service of one another the possibility for architectural expression rather than simple building is created. One does not revere great architects solely for their philosophies of design, the functionality of the spaces they create, the materials with which they construct them, or the regulating devices they employ, but rather for the complexity with which these elements are brought together to form a whole so well designed that it seems that it could have been done no other way.Master of Architecture
47
Tinsley, Carl Terrie III. "Modeling of Multi-Pulse Transformer/Rectifier Units in Power Distribution Systems." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/34655.
Abstract:
Multi-pulse transformer/rectifier systems are becoming increasingly popular in power distribution systems. These topologies can be found in aircraft power systems, motor drives, and other applications that require low total harmonic distortion (THD) of the input line current. This increase in the use of multi-pulse transformer topologies has led to the need to study large systems composed of said units and their interactions within the system. There is also an interest in developing small-signal models so that stability issues can be studied.
This thesis presents a procedure for the average model of multi-pulse transformer/rectifier topologies. The dq rotating reference frame was used to develop the average model and parameter estimation is incorporated through the use of polynomial fits. The average model is composed of nonlinear dependent sources and linear passive components. A direct benefit from this approach is a reduction in simulation time by two orders of magnitude. The average model concept demonstrates that it accurately predicts the dynamics of the system being studied. In particular, two specific topologies are studied, the 12-pulse hexagon transformer/rectifier (hex t/r) and the 18-pulse autotransformer rectifier unit (ATRU). In both cases, detailed switching model results are used to verify the operation of the average model. In the case of the hex t/r, the average model is further validated with experimental data from an 11 kVA prototype. The hex t/r output impedance, obtained from the linearized average model, has also been verified experimentally.Master of Science
48
Stewart, Nathan Todd. "Treatment of Rainbow Trout (Oncorhynchus mykiss) Raceway Effluent Using Baffled Sedimentation and Artificial Substrates and Characterization of Nutrient Leaching Rates from Settled Rainbow Trout (Oncorhynchus mykiss) Sludge." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34555.
Abstract:
Treatment of Rainbow Trout (Oncorhynchus mykiss) Raceway Effluent Using Baffled Sedimentation and Artificial Substrates
The treatment performance of a 6 m wide by 67 m long by 0.8 m deep, baffled sedimentation basin receiving rainbow trout (Oncorhynchus mykiss) raceway effluent was evaluated with and without the installation of artificial substrates (Aquamats®). Treatment efficiency was also determined using normal rearing condition effluent loading versus cleaning and harvesting events. Total suspended solids (TSS) removal for the total basin averaged 79% and 71% during normal rearing conditions, as compared to 92% and 79% during cleaning and harvesting operations, when the Aquamats® were installed versus removed, respectively. Total phosphorus (TP) removal by the total basin, with and without Aquamats®, was 20% and 23% during normal rearing conditions as compared to 55% and 65% under cleaning and harvesting conditions, respectively. Higher TP removal during cleaning operations was attributed to sedimentation of particulate fractions. Dissolved nutrient removal (ortho-phosphate (OP), total ammonia nitrogen (TAN), nitrate, nitrite, and total organic carbon (TOC)) was not consistent throughout the basin and did not improve when the Aquamats® were installed. A short contact time and periphyton grazing by isopods may have limited the capacity of the Aquamats®.
Calculated retention times with and without Aquamats® for the first half and total basin were 37% and 32% and 27% and 17% less than theoretical values, respectively based on a rhodamine WT dye study. Average surface overflow rates were adjusted accordingly and measured 19.1 m3/m2-day when the Aquamats® were installed, versus 14.8 m3/m2-day when the Aquamats® were removed for the overall basin. These rates are lower than previous recommendations for treating aquaculture effluents, but resulted in with high solids removal and consistently low TSS effluent (average < 2 mg/L) which may be necessary for strict discharge permits. Use of the overall basin minimized the occurrence of TSS measurements > 2 mg/L by 50%. For the first half of the sedimentation basin, the overflow rate averaged 44.1 m3/m2-day with Aquamats® versus 35.8 m3/m2-day without Aquamats®. The majority of effluent treatment occurred within the first half of the basin, which was responsible for 84% and 94% of total TSS removal, 42% and 100% and 61% and 80% of total TP removal during normal and cleaning/harvesting conditions, respectively.
Characterization of Nutrient Leaching Rates from Settled Rainbow Trout (Oncorhynchus mykiss) Sledge
The leaching of nutrients from settled rainbow trout (Oncorhynchus mykiss) sludge into overlying water was evaluated over a 7 day period. Nutrient leaching was assessed in a stagnant reaction tank and one agitated by aeration to simulate turbulent conditions in stocked production raceways. Leaching of total phosphorus (TP), ortho-phosphate (OP), total Kjeldahl nitrogen (TKN), total ammonia nitrogen (TAN), and total organic carbon (TOC) occurred rapidly during the first 24 h in both stagnant and agitated conditions. The highest 24 h leaching occurred in the agitated tank, and power regression equations accurately described the varying rates of increasing TP, OP, TAN and TKN. In the stagnant tank, linear increases of TP, OP, TKN and TAN concentrations occurred during the first 24 h. These linear increases continued from day 2-7, but at slower rates than occurred during the first 24 h. Average nutrient leaching rates (mg leached/g sludge-h);(dry weight basis) were calculated based on linear concentration increases. In the agitated tank, nutrient concentrations decreased after 60 h, as aerobic bacterial uptake and/or chemical precipitation was suspected. Therefore, average leaching rates could not be determined.
These findings reveal that daily cleanout of settling areas could eliminate the release of TP, OP, TAN, TKN, and TOC from settled solids by 66%, 65%, 39%, 76% and 51%, respectively, as compared to weekly cleanout schedules. Sustained leaching rates indicate nutrient release will likely continue beyond 7 days. This information suggests aggressive and continuous sludge management is most beneficial for maintaining high water quality and regulatory discharge compliance in fish production.
Master of Science
49
Williams, Ryan Williams. "Application of Spatial Analysis in the Incidence of the Gall Midge in Jamaican Hot Pepper Production." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34155.
Abstract:
Jamaican farmers are experiencing constraints to hot pepper (Capsicum chinense) export production due to a quarantine pest -- the gall midge (Contarinia lycopersici; Prodiplosis longifila). There is a threat of gall midge introduction into the United States, where the insect pest is not known to occur. This research tests the significance of a range of variables to gall midge incidence. The purpose was to explain the spatial patterns that result from the relationships between gall midge incidence in hot pepper production and production methods and/or environmental conditions. There were three components to the sample of 47 farm visits: the interview, the hot pepper sampling, and the measurements of physical and locational attributes. Producers responded to questions about production methods, marketing, and quarantine issues. The percent of infested fruits per plot was calculated. GPS was used to record farm location. Using ArcView, environmental and climatic datasets were overlaid with farm locations and their attributes. Multiple regression was used to measure significance of variables to gall midge incidence. Cluster analyses were used to demonstrate the spatial patterns of the variability of gall midge incidence and its associated variables. There was significant effect on incidence by farm elevation, observance of pesticide-use recommendations, producer awareness of pre-clearance fumigation, and the use of intercropping in hot pepper production.Master of Science
50
Sherlock, Jay T. "Synthesis." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/34055.
Abstract:
This thesis is an investigation of place. The project is a vehicle which informs how the variables of site and program can be developed into place. Through the production of tangible work the architect may verify whether the creation of place is successful. The analysis of this outcome can enhance and reinforce the architect's position.Master of Architecture