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

Biostatistical and meta-research approaches to assess diagnostic test use

O'Sullivan, Jack William January 2018 (has links)
The aim of this thesis was to assess test use from primary care. Test use is an essential part of general practice, yet there is surprisingly little data exploring and quantifying its activity. My overarching hypothesis was that test use from primary care is sub-optimal, specifically that tests are overused (overtesting) - ordered when they will lead to no patient benefit, and underused (undertesting) - not ordered when they would lead to patient benefit. Previous metrics used to identify potential over and undertesting have been categorised into direct and indirect measures. Indirect measures take a population-level approach and are 'unexpected variation' in healthcare resource use, such as geographical variation. Direct measures consider individual patient data and directly compare resource use with an appropriateness criterion (such as a guideline). In this thesis, I examined three indirect measures: temporal change in test use, between-practice variation in test use and variation between general practices in the proportion of test results that return an abnormal result. In chapter 3, I identified which tests have been subject to the greatest change in their use from 2000/1 to 2015/16 in UK primary care. In chapter 4, I identified the tests that had been subject to the greatest between-practice variation in their use in UK primary care. In chapter 5, I present a method to identify General Practices whose doctors order a lower proportion of tests that return a normal result. In chapter 6, I present a method to directly quantify over and undertesting; I conducted a systematic review of studies that measured the adherence of general practitioner's test use with guidelines. In chapter 7 I acknowledge that the use of guidelines to audit general practitioner's test use is flawed; guidelines are of varying quality and not designed to dictate clinical practice. In this chapter, I determine the quality and reporting of guidelines, the quality of the evidence underpinning their recommendations and explore the association between guideline quality and non-adherence. Overall, I have shown that most tests have increased substantially in use (MRI knee, vitamin D and MRI brain the most), there is marked between-practice variation in the use of many tests (drug monitoring, urine albumin and pelvic CT the most) and that some general practices order a significantly lower proportion of tests that return an abnormal result. I have also shown that there is marked variation in how often GPs follow guidelines, but guidelines based on highly quality evidence are adhered to significantly more frequently. Lastly, in my Discussion chapter, I discuss the implications of my thesis, how it fits into the wider literature and an idea for a proposed step-wise approach to systematically identify overtesting.
2

Closed-loop Greenhouse Agriculture Systems

Ragany, Michelle January 2024 (has links)
The growing global population and climate change threaten the availability of many critical resources, and have been directly impacting the food and agriculture sector. Therefore, new cultivation technologies must be rapidly developed and implemented to secure the world's future food needs. Closed-loop greenhouse agriculture systems provide an opportunity to decrease resource reliance and increase crop yield. Greenhouses provide versatility in what can be grown and the resources required to function. Greenhouses can become highly efficient and resilient through the application of a closed-loop systems approach that prioritizes repurposing, reusing, and recirculating resources. Here, we employ a text mining approach to research the available research (meta-research) and publications within the area of closed-loop systems in greenhouses. This meta-research provides a clearer definition of the term “closed-loop system” within the context of greenhouses, as the term was previously vaguely defined. Using this meta-research approach, we identify six major existing research topic areas in closed-loop agriculture systems, which include: models and controls; food waste; nutrient systems; growing media; heating; and energy. Furthermore, we identify four areas that require further urgent work, which include the establishment of better connection between academic research to industry applications; clearer criteria surrounding growing media selection; critical operational requirements of a closed-loop system; and the functionality and synergy between the many modules that comprise a closed-loop greenhouse systems. / Thesis / Master of Applied Science (MASc)
3

[en] CONCEPTIONS OF TECHNOLOGY IN BRAZILIAN EDUCATIONAL RESEARCH IN EDUCATION AND TECHNOLOGY / [pt] CONCEPÇÕES DE TECNOLOGIA NA PESQUISA EDUCACIONAL BRASILEIRA EM EDUCAÇÃO E TECNOLOGIA

MARIA PAULA ROSSI NASCENTES DA SILVA 23 August 2021 (has links)
[pt] A presente tese intitulada Concepções de tecnologia na Pesquisa Educacional Brasileira em Educação e Tecnologia é um estudo que se insere entre as pesquisas desenvolvidas no interior do Grupo de Pesquisa Formação de Professores e Tecnologia (ForTec) no período entre 2014 e 2020, do Programa de Pós-Graduação em Educação da Pontifícia Universidade Católica do Rio de Janeiro (PPGE/PUC-Rio). Nesta tese elencamos como objetivo identificar as concepções de tecnologia adotadas na produção acadêmica da área de Educação e Tecnologia. Para tanto, realizamos um levantamento das teses e dissertações produzidas em Programas de Pós-Graduação Stricto Sensu em Educação defendidas no período de 2010 a 2019 e disponibilizadas no Catálogo de Teses e Dissertações CAPES. Assumimos como hipótese desta pesquisa que, ao analisar as concepções sobre tecnologia nas teses e dissertações, podemos refletir criticamente sobre as concepções que estão em uso e suas contribuições para o desenvolvimento das pesquisas na área de Educação e Tecnologia. Para analisar tais concepções partimos de um escopo teórico que vem da própria pesquisa em Educação e Tecnologia (Pischetola, 2018; Pischetola & Miranda, 2019; Peixoto, 2015; Selwyn, 2011, 2015, 2017a, 2017b), da Comunicação (McLuhan, 1964; Postman, 1993), da Filosofia (Pinto, 1989, 2005) e da Filosofia da Tecnologia (Dusek, 2009a; Feenberg, 2003, 2004, 2009). Por conta disso, elencamos três definições de tecnologia, a saber: tecnologia como ferramenta, tecnologia como regra e tecnologia como ecologia. Para analisar os trabalhos mapeados no levantamento realizamos Análise de Conteúdo (Bardin, 2016). Os dados encontrados nos trabalhos indicam uma forte tendência da concepção de tecnologia como ferramenta e geralmente associada a sua utilização pelos professores como suporte à tarefa pedagógica. Embora com conteúdo crítico, as concepções adotadas nos trabalhos sugerem uma consciência ingênua em relação à tecnologia. Dentro da categoria tecnologia como ecologia, um número significativo de estudos desponta com concepções mais críticas de tecnologia apoiando-se na Filosofia Crítica da Tecnologia, de Andrew Feenberg e nas reflexões de Álvaro Vieira Pinto. A aproximação dos autores dos estudos mapeados com outras áreas do conhecimento, como Filosofia e Sociologia, contribuiu para a concepção de tecnologia como ecologia na medida que são considerados na relação educação e tecnologia outros fatores que intervém no contexto mesmo não estando concretamente presentes. / [en] The present thesis entitled Conceptions of technology in Brazilian Educational Research in Education and Technology is a study whose origin is due to the research developed within the Teacher Education and Technology Research Group (ForTec) in the period between 2014 and 2020 of the Graduate Program in Education of the Pontifícia Universidade Católica of Rio de Janeiro (PPGE/PUC-Rio). In this thesis, it was set as our objective to identify the conceptions of technology adopted in the academic production in the area of Education and Technology. To this end, we conducted a survey of the theses and dissertations produced in Scricto Sensu Graduate Programs in Education defended in the period from 2010 to 2019 and available in the CAPES Theses and Dissertations Catalog. We assume as hypothesis of this research that, by analyzing the conceptions about technology in theses and dissertations, we can critically reflect on the conceptions that are in use and their contributions to the development of research in the area of Education and Technology. To analyze such conceptions, we start from a theoretical scope that comes from the research itself in Education and Technology (Pischetola, 2018, 2019; Peixoto, 2015; Selwyn, 2011, 2015, 2016), da Communication (McLuhan, 1964; Postman, 1993), da Filosofia (Pinto, 1989, 2005) Philosophy of Technology (Dusek, 2009a; Feenberg, 2003, 2004, 2009). Because of this, we listed three definitions of technology, namely: technology as a toll, technology as rules, and technology as ecology. To analyze the works mapped in the survey, we conducted Content Analysis (Bardin, 2016). The data found in the papers indicate a strong tendency of the conception of technology as a tool and is generally associated with it use by teachers as a support to the pedagogical task. Although with critical content, the conceptions adopted in the studies suggest a naïve consciousness in relation to technology. Within the category technology as ecology, a significant number of studies show more critical conceptions of technology based on Andrew Feenberg s Critical Philosophy of Technology and Álvaro Vieira Pinto s reflections. The approach of the mapped authors of the studies with other areas of knowledge, such as Philosophy and Sociology, contributed to the conception of technology as ecology insofar as other factors that are considered in the relation between education and technology intervene in the context even if they are not concretely present.
4

Cartographie globale des essais cliniques / World mapping of clinical trials

Atal, Ignacio 23 November 2017 (has links)
Pour comprendre comment se construisent les connaissances sur l’effet des interventions en médecine, il est nécessaire de savoir où est faite la recherche clinique dans le monde, quelles maladies sont étudiées, et quels acteurs la mettent en place. Une vision globale du système de recherche peut aider à identifier des lacunes dans la production de connaissances et à orienter l’activité de recherche vers les priorités de santé, en particulier dans les régions où les ressources sont limitées. Dans ce travail nous avons construit des cartographies de la recherche clinique, c’est-à-dire des analyses agrégées de ce système complexe visant à extraire de l’information sur l’activité globale de recherche. Nous avons utilisé les registres d’essais cliniques inclus dans l’International Clinical Trials Registry Platform de l’Organisation Mondiale de la Santé pour cartographier l’activité de recherche. Dans un premier travail nous avons évalué pour 7 régions l’alignement entre l’effort local de recherche sur 10 ans et le fardeau de 27 groupes de maladies. Ce travail a nécessité le développement d’un algorithme de classification automatique des maladies étudiées dans les essais clinique basé sur des méthodes de traitement automatique du langage. À partir des données de 117,180 essais randomisés, nous avons montré que la recherche faite dans les pays riches était bien alignée avec leurs besoins. Dans toutes les autres régions nous avons identifié des lacunes dans l’effort de recherche. En particulier, en Afrique Subsaharienne, même si des causes majeures de fardeau comme le VIH et le paludisme reçoivent un effort de recherche important, d’autres priorités locales, les maladies infectieuses communes et les pathologies du nouveau-né, ont été négligées par l’effort de recherche. Dans un deuxième travail nous avons évalué l’influence du type de promoteur (industriel ou non-industriel) dans l’utilisation de réseaux de pays pour recruter des patients dans des essais cliniques multi-pays. Nous avons montré que 30% contre 3% des essais à promoteur industriel et non-industriel sont multi-pays, respectivement. Les pays d’Europe de l’Est participent dans leur ensemble de façon surreprésentée dans la recherche multi-pays industrielle. Ceci suggère les grandes capacités des industriels à globaliser leur recherche en s’appuyant sur des réseaux de pays bien définis. À l’échelle de tous les essais clinique enregistrés, nos travaux ont mis en évidence des lacunes majeures dans l’effort de recherche mondial, et montré l’influence des différents acteurs dans la globalisation de celle-ci. Ces travaux forment une brique pour le développement d’un observatoire global de la recherche médicale. / By knowing what clinical research is undertaken worldwide, where it is conducted, which diseases are studied, and who is supporting it, we could have a better understanding on how is created the knowledge concerning health interventions. A global landscape of health research may inform policy makers on knowledge gaps and on how to reallocate resources to address health needs, in particular in low-resource settings. In this thesis we mapped clinical research, i.e. we analyzed at a macro-level the complex system of health research to bring information on the global landscape of health research effort. We based our analyses on clinical trial registries included in the International Clinical Trials Registry Platform from the World Health Organization. In a first project, we evaluated within 7 regions the local alignment between the effort of research and the burden for 27 groups of diseases. This work needed the development of a knowledge-based classifier of clinical trial registries according to diseases studied based on natural language processing methods. We mapped 117,180 randomized controlled trials. For high-income countries, the research effort was well aligned with the needs. In all other regions we identified research gaps. In particular, for Sub-Saharan Africa, where major causes of burden such as HIV and malaria received a high research attention, research was lacking for major causes of burden, especially for common infectious diseases and neonatal disorders. In a second project, we compared the mappings of multi-country trials for industry- and non-industry–sponsored clinical trials, and analyzed the networks of collaboration of countries participating together to the same multi-country trials. We showed that among industry- and non-industry–sponsored trials, 30% and 3% were multi-country, respectively. The collaboration within Eastern European countries was particularly over-represented for industry-sponsored research. Industry sponsors may thus have a greater capacity to conduct globalized research, using well-defined networks of countries. Our large-scale mappings of all registered clinical trials shed light on major gaps in the effort of health research as compared to health needs. In addition, we showed the influence of different sponsors in the globalization of clinical research. These projects are in-line with the development of a global observatory for health research.
5

Probabilistic Dynamic Resilience of Critical Infrastructure in Multi-Hazard Environments

Badr, Ahmed January 2024 (has links)
Critical Infrastructure Systems (CISs) are key for providing essential services and managing critical resources. The failure of one CIS can result in severe consequences on national security, health & safety, the environment, social well-being, and the economy. However, CISs are inherently complex, operating as systems-of-systems with dynamic, non-linear, and uncertain operation conditions, all geared towards fulfilling complex operational objectives. The complexity of both system architecture and operational objectives contributes to challenges in comprehending system-level behavior under normal and disruptive conditions. CISs are also highly exposed to multi-hazard environments characterized by probabilistic behaviors that can impact one or more system components—leading to diverse system failure modes. Understanding the dynamic interaction between hazards and the system response in such environments adds another layer of complexity to CISs safety. Addressing such complexity is crucial and it necessitates thorough investigations to ensure the continuous and reliable operation of CISs. Accordingly, the main objective of this thesis is to develop dynamic resilience quantification approaches for CISs in multi-hazard environments, considering the probabilistic behavior of both the hazard and the system. Given that dam infrastructure is one of the most significant CISs, this thesis employs an actual dam system as a demonstration application for the developed models. Nonetheless, it should be emphasized that the thesis focuses on the generalizability of the developed model to the CISs rather than the specificities related to dam systems, which are adopted herein merely to show the utility of the developed models to complex CISs. Specifically, this thesis first employs a meta-research approach (Chapter 2), using text analytics, to conduct a quantitative and qualitative review of extensive prior research focused on CISs operational safety, considering dam and reservoir systems as one of the key CISs. Such meta-research aims to unveil latent topics in the field and identify key opportunities for future research, particularly in addressing limitations associated with existing risk-based and resilience-based safety assessment approaches for CISs. To overcome such limitations, this thesis (Chapter 3) subsequently developed a coupled Continuous-Time Markov Chain and Bayesian network, facilitating the dynamic quantification of CISs failure risk (propagation of the system's probability of failure with time), considering the temporal variation of uncertainties in system components during operations. Starting from where the risk-based assessment ends (the immediate response of the system at the hazard realizations), resilience-based assessment focuses more on the dynamic system functionality gain/reduction and, subsequently, the system deterioration and recovery rates following hazard realizations. Accordingly, this thesis (Chapter 4) presents a resilience-centric System Dynamics simulation modeling approach capable of representing CISs components, estimating their dynamic system performance, and subsequent dynamic resilience (propagation of the system resilience with time). Such a modeling approach proposes a combinatorial procedure for generating multi-hazard scenarios, encompassing both natural and anthropogenic hazards, where one primary hazard can trigger one or more subsequent hazards. As a result, the developed models can investigate system operations under both single and multi-hazard environments. Furthermore, the coupling between System Dynamics and Monte Carlo simulations (Chapter 5) enables the model to seamlessly incorporate the probabilistic behaviors of both multi-hazard and system responses. The developed approaches can provide the decision-makers with a more detailed system representation that includes probabilistic dynamic system components with multi-operational objectives under probabilistic multi-hazard environments (Chapter 6). Moreover, the developed models can introduce more realistic evaluations for risk-adaptive and mitigation plans in real-time, contributing to more efficient safety assessment plans for the CISs. / Thesis / Doctor of Philosophy (PhD) / Critical infrastructure systems (CISs) play pivotal roles in delivering and supporting the essential needs of our daily lives. However, ensuring the safety of CISs poses layered challenges due to the complexity of their systems and operations, compounded by their susceptibility to multi-hazard environments, all with probabilistic behaviors. Recognizing the criticality and safety obstacles associated with CISs, this thesis introduces dynamics resilience quantification approaches for CISs safety based on a holistic system dynamics representation. The developed models are designed to enhance understanding of the system's performance under multi-hazard disruption conditions, considering the probabilistic behavior of both hazards and system response. Moreover, these models yield resilience-based metrics, allowing for the evaluation of the effectiveness of various risk mitigation plans, which would subsequently lead to more reliable safety assessment plans for CISs. Considering that dam infrastructure is a key CISs, this thesis focuses on the former as a demonstration application to show the developed models’ utility and their efficiency in devising resilience-guided assessment plans for CISs.
6

Statistical practice in preclinical neurosciences: Implications for successful translation of research evidence from humans to animals

Hogue, Olivia 23 May 2022 (has links)
No description available.

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