Dissertations / Theses on the topic 'Longitudinal Value'
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Ledden, Lesley. "The dynamic nature of value : a longitudinal study." Thesis, Kingston University, 2009. http://eprints.kingston.ac.uk/20283/.
Full textMcLaren, Josephine Anne. "Can EVA™ create value? : a dynamic longitudinal investigation of three New Zealand companies." Thesis, University of Newcastle upon Tyne, 2012. http://hdl.handle.net/10443/2875.
Full textLange, Joshua. "Exploring value through international work placements in social entrepreneurial organisations : a multiple case longitudinal study." Thesis, University of Exeter, 2015. http://hdl.handle.net/10871/22106.
Full textPrint, Carole. "An exploratory longitudinal study of the implementation of shareholder value within three large international companies." Thesis, Henley Business School, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288764.
Full textConnor, Paul Brereton. "Exploring customer perceived value change in an UK aerospace manufacturing company : a longitudinal case study." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/28661/.
Full textGundogdu, Didem. "The role of social and human capital in assessing firm value : a longitudinal study of UK firms." Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/30194.
Full textSilva, Rodrigo Alves. "Viabilidade de utilização da teoria de opções reais no processo de avaliação de empresas de telecomunicações." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18157/tde-08102010-084629/.
Full textThe process of business valuation for formal models and techniques aims to guide the management and stakeholder groups as to the optimal decision-making. In general, in the evaluating process these models are used following assumptions about the value of the firm benefits, giving the connotation that business value is the value of these benefits. In companies that operate in markets with high competitiveness and high level of development and use of technologies and innovations, the isolated use of techniques focused on the benefits of today\'s businesses have shown inadequate to assess the organization ability in response to marketing variables. From that perspective, the benefits arising from competitive strategies and minimization of business loss chances, mainly won through relaxation strategies and generating new business opportunities to show important value drivers. The value generated by the opportunities and flexibilities in the firm\'s telecommunications companies is the focus of this research that aims to support in their discussions and tests the feasibility of incorporating the real options model in the evaluation of companies in the sector, on the assumption that the market, seeing the importance of strategies for investment management and company structure for its success in generating value, remunerate these organizations, assigning the value according to your expectations. Models of fixed and random effects panel data were tested to assess the significance of the explanatory variables generating potential value of real options. The tests demonstrate statistical significance of the variables, basing the model. Nevertheless, this research positions studies and theoretical surveys about the valuation models addressed in order to contextualize the usefulness of the real options model in evaluation processes, and highlights the applicability of the real options model procedural in conjunction with the technique of cash flow discounted in evaluating companies. The goals for discussion and annotation of the theory applicability are achieved, given the set of empirical and illustrative of this technique.
Deng, Cheng. "Time Series Decomposition Using Singular Spectrum Analysis." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etd/2352.
Full textHoang, Thinh Quoc. "Exploring Vietnamese first-year English-major students’ motivation: A longitudinal, mixed-methods investigation." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2021. https://ro.ecu.edu.au/theses/2423.
Full textDalben, Adilson 1965. "Fatores associados à proficiência em leitura e matemática : uma aplicação do modelo linear hierárquico com dados longitudinais do Projeto GERES." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/253935.
Full textTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Educação
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Resumo: Esta pesquisa é um estudo sobre a eficácia e equidade escolar que tem ganhado atenção especial nos países que usam as avaliações em larga escala a serviço da gestão do sistema educativo. No Brasil, que desde a década de 1990 colocou a avaliação educacional como recurso central em suas políticas educacionais, mas coletando dados seccionais, que são muito frágeis para essa finalidade. Essa fragilidade decorre da alta associação que os fatores extraescolares, sobretudo o nível socioeconômico do aluno, têm sobre as medidas de proficiência. Diante disso, foram usados dados longitudinais e a análise foi feita por meio de modelos lineares hierárquicos. Esta pesquisa teve como objetivo principal desenvolver um modelo estatístico capaz de identificar tais fatores para a realidade brasileira, considerando que a aprendizagem é um processo complexo, isto é, ela é influenciada simultaneamente por múltiplos fatores. Foram desenvolvidos modelos de valor agregado que não só identificam tais variáveis, como também caracterizam sua influência em alunos com distintas proficiências no início de cada período de escolarização. A base de dados utilizada nesses modelos foi fornecida pelo Projeto GERES, que, no período de 2005 a 2008, coletou dados dos mesmos alunos de 1ª a 4ª séries de uma amostra de 312 escolas em cinco grandes cidades brasileiras. Foram medidas as proficiências em Leitura e Matemática de 35.538 alunos e coletadas informações de contexto desses alunos, seus familiares, professores, diretores e escola. Após a redução do grande número de informações disponibilizadas pelo Projeto GERES, feita por meio da Análise Fatorial Exploratória (AFE), as variáveis resultantes foram reorganizadas em três arquivos usados para análise em modelos lineares hierárquicos de três níveis. Os resultados encontrados evidenciam uma significativa instabilidade nos efeitos que as variáveis têm sobre a proficiência, tanto em leitura quanto em matemática. Ao final da pesquisa, são encontrados alguns fatores que influenciam positivamente e negativamente a proficiência em Leitura e Matemática e outros que afetam especificamente cada uma dessas áreas, indicando que podem colaborar para o aumento da eficácia e da equidade das escolas. No entanto, constatam-se também algumas variáveis que têm comportamentos incoerentes com o esperado e outras com comportamentos opostos nas duas áreas. Assim, dos achados das pesquisas, comprova-se que, com base nos dados utilizados, procedimentos metodológicos e modelos estatísticos adotados, os modelos de valor agregado melhoram a confiabilidade das análises em comparação aos modelos que usam dados seccionais, mas ainda são inviáveis como ferramentas para a gestão do sistema educativo, sobretudo para o uso meritocrático de seus resultados. Dessa forma, esta pesquisa corrobora os achados de outras realizadas no âmbito internacional e permite afirmar que a qualidade da modelagem estatística depende da qualidade dos dados que busca modelar, podendo gerar distorções, estabelecer relações inesperadas ou levar a conclusões equivocadas. Em contrapartida, trata-se de recursos que podem ser usados no sistema educativo, fornecendo dados importantes para a orientação das políticas públicas numa perspectiva de avaliação formativa, com vistas ao melhoramento da qualidade de ensino oferecido pelas escolas e à melhor formação dos profissionais docentes e não-docentes que nelas trabalham
Abstract: This research is a study on school effectiveness and equality in Brazil, adding up to a number of other researches that have drawn special attention in countries that use large-scale evaluations at the service of the education system management. In the Brazil has regarded the educational evaluation as a central resource in national education policies, but using cross-sectional data, which are far more fragile for such purpose. This fragility has derived from the great influence that extra-school factors, particularly the students¿ socioeconomic status, exerts on proficiency measures. Longitudinal data was used in the analyses with hierarchical linear models. The main objective of this research was to develop a statistical model to identify such factors in the Brazilian reality, considering that learning is a complex process, i.e. it is simultaneously influenced by multiple factors. Value-added models were developed not only to identify such variables, but also to characterize their influence on students showing different proficiencies at the beginning of every school term. The data base used in those models was provided by the GERES Project, which collected data of the same students from the 1st to the 4th grade from a sample of 312 schools in five Brazilian cities from 2005 to 2008. Proficiencies of 35,538 students were measured, and information about these students¿ context, family, teachers, principals and school were gathered. After the reduction of the great amount of information made available by the GERES Project by means of Exploratory Factor Analysis (EFA), the resulting variables were reorganized in three files used for analysis in three-level hierarchical linear models. The results evidenced significant instability in the effects that the variables have on proficiency both in Reading and in Mathematics. At the end of the research, some factors that influence Reading and Mathematics proficiency either positively or negatively, as well as other factors that specifically affect one of those areas, were found, thus indicating that they may contribute to increased school effectiveness and equality. However, some variables whose behavior was inconsistent with the one expected, and others with opposite behaviors in the two areas were also found. Therefore, from the research findings, based on the data used, the methodological procedures and the statistical models adopted, it has been evidenced that value-added models improve the analysis reliability in comparison with models that use cross-sectional data, but they are still impracticable as tools for education system management, particularly for meritocratic use of their results. Hence, this research has corroborated the findings of other studies carried out over the world and has enabled us to state that the quality of the statistical modeling depends on the quality of data that it attempts to model, and it may generate distortions, establish unexpected relationships or lead to misleading conclusions. On the other hand, these resources may be used in the education system by providing important data for guiding public policies in a educative evaluation perspective, aiming at improving the quality of teaching offered by schools, teachers and other professionals that work in the school setting
Doutorado
Ensino e Práticas Culturais
Doutor em Educação
Ghallab, Eman. "Exploring the pedagogical value and challenges of using e-portfolios as a learning tool for nursing students : a single longitudinal qualitative case study with Activity Theory as an analytical framework." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/48373/.
Full textSousa, Júnior Severino Cavalcante de [UNESP]. "Persistência da lactação e Influência da estrutura de dados sobre a estimação de parâmetros genéticos para a produção de leite de bovinos da raça Holandesa." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/104906.
Full textConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Para o presente estudo foram utilizadas 3.202 primeiras lactações, de vacas da raça Holandesa pertencentes a quatro fazendas da região Sudeste, registradas semanalmente, com o objetivo de verificar a influência da estrutura de dados de produção de leite no decorrer da lactação, sobre os parâmetros genéticos estimados por modelos de regressão aleatória. Foram testados quatro arquivos contendo estruturas diferentes de dados. O arquivo de controles semanais (CS) contava com 122.842 controles, o arquivo mensal (CM) com 30.883 controles, o bimestral (CB) com 15.837 controles, e por fim, o arquivo de controles trimestrais (CT) continha de 12.702 controles. O modelo utilizado foi o de regressão aleatória, e como aleatórios foram considerados os efeitos genético aditivo e o de ambiente permanente de animal. A ordem das funções de covariância para estes dois efeitos foi de sexta ordem para efeito genético aditivo e de sétima ordem para o efeito de ambiente permanente, com variâncias residuais heterogêneas a estrutura de variâncias residuais foi modelada por meio de uma “step function” O modelo teve como efeito fixo os grupos de contemporâneos (GC) comuns para todos os arquivos de dados. Os GC foram compostos por fazenda, mês e ano do controle,e como co-variável a idade da vaca ao parto (regressão linear e quadrática) e o número de dias em lactação (regressão fixa para a média populacional). Todos os arquivos de dados estudados foram analisados incluindo arquivo de genealogia composto por 4.380 animais com 3202 mães e 228 touros. As estimativas de herdabilidades para produção de leite apresentaram tendências semelhantes entre os arquivos de dados analisados, com maior semelhança entre os bancos CS, CM e CB. As estimativas de herdabilidade para produção de leite no dia do controle (PLDC) do banco CT apresentou pequenas diferenças, em relação aos demais...
To this study the first 1293 Holstein dairy lactation registered weekly were used, having cows belonging to four farms in the Southeast region of Brazil, aiming verify the milk production data structure influence during lactation under genetic parameters estimated by random regression models. Four files with different data structures were tested. The week control files (CS) counted with 122,842 controls; the month files (CM), 30,883 controls; the bimestrial (CB) had 15,837 controls and finally the quarterly (CT) had 12,702 controls. It was used the random regression model and, as random, the genetic additive and the animal permanent environmental effects were considered. The covariance function to these two effects was the sixth grade to the genetic effect additive and the seventh grade to the permanent environmental effect, having heterogeneous residual variances, and the residual variance structure was modeled by a “step function”. The model had as the fixed effect the contemporaneous groups (GC) commons to all data set, GC were compounded by farm, month, and year of control. The co-variable was the cow age at birth (linear and quadratic regression) and the milking days (fixed regression to the population average). All evaluated data files presented genealogy file composed by 4,380 animals having 1,416 mothers and 228 bulls. The estimate of heritability presented tendencies similar among the analyzed data, having the higher similarity CS, CM and CB. The CT presented small differences in the estimate of heritability when compared to the others. The CB data file presented all the analyzed genetic parameters estimative with the same tendency and magnificence of the CS and CM, allowing the milk control in a CB structure, random regression model in genetic evaluations speaking. The genetic values (VG) to partial milking period production were predicted (MRA100, MRA200, MRA300 e MRA90_305) ...(Complete abstract click electronic access below)
Schiratti, Jean-Baptiste. "Methods and algorithms to learn spatio-temporal changes from longitudinal manifold-valued observations." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX009/document.
Full textWe propose a generic Bayesian mixed-effects model to estimate the temporal progression of a biological phenomenon from manifold-valued observations obtained at multiple time points for an individual or group of individuals. The progression is modeled by continuous trajectories in the space of measurements, which is assumed to be a Riemannian manifold. The group-average trajectory is defined by the fixed effects of the model. To define the individual trajectories, we introduced the notion of « parallel variations » of a curve on a Riemannian manifold. For each individual, the individual trajectory is constructed by considering a parallel variation of the average trajectory and reparametrizing this parallel in time. The subject specific spatiotemporal transformations, namely parallel variation and time reparametrization, are defined by the individual random effects and allow to quantify the changes in direction and pace at which the trajectories are followed. The framework of Riemannian geometry allows the model to be used with any kind of measurements with smooth constraints. A stochastic version of the Expectation-Maximization algorithm, the Monte Carlo Markov Chains Stochastic Approximation EM algorithm (MCMC-SAEM), is used to produce produce maximum a posteriori estimates of the parameters. The use of the MCMC-SAEM together with a numerical scheme for the approximation of parallel transport is discussed. In addition to this, the method is validated on synthetic data and in high-dimensional settings. We also provide experimental results obtained on health data
Mayeli, Nader. "An experimental study of the unrestrained shrinkage of isotropic paper sheets." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/an-experimental-study-of-the-unrestrained-shrinkage-of-isotropicpaper-sheets(6f0e3356-2e17-4433-8303-723a863c11f0).html.
Full textHombourger-Barès, Sabrina. "La contribution du design de l'espace de vente à l'évolution du positionnement de l'enseigne : une analyse longitudinale." Thesis, Dijon, 2014. http://www.theses.fr/2014DIJOE002/document.
Full textOne of the innovative ways favoured by retailers to drive change in their value proposition is to review the design of their stores. Academic contributions to the in-store experience have mostly focused on consumer perspective and identifying relevant managerial practices. The core of this research studies how repositioning a retail brand translates into the experiential design of retail spaces. To this end, the research follows the repositioning process from a managerial perspective and updates the mechanisms that underlie it. The longitudinal study of embedded cases reveals the importance of an holistic design that takes into account the desired interactions between the shopper and the store. The analysis shows the four overlapping phases of the store’s life cycle, and breaks down the process into six dimensions, each with its own events and issues. The six dimensions are vision, plotline, action, decor, assessment and coproduction.The entrepreneurial vision of the leader is the cornerstone of the whole innovation process. The value proposition is embodied by three components, namely plotline, action and decor. For each of the five stages of the shopper’s journey, elements of the decor are implemented to relay or reinforce the desired action. These are mechanisms or devices meant to stimulate the shopper’s experiential system. The assessment, which involves measuring the perceived and experienced positioning, helps to adjust the value proposition in terms of four levels of consistency and flexibility of design. Finally, the coproduction of store design between different stakeholders can cause a co-destruction of value, whether intentional or accidental
Sousa, Júnior Severino Cavalcante de. "Persistência da lactação e Influência da estrutura de dados sobre a estimação de parâmetros genéticos para a produção de leite de bovinos da raça Holandesa /." Jaboticabal : [s.n.], 2010. http://hdl.handle.net/11449/104906.
Full textAbstract: To this study the first 1293 Holstein dairy lactation registered weekly were used, having cows belonging to four farms in the Southeast region of Brazil, aiming verify the milk production data structure influence during lactation under genetic parameters estimated by random regression models. Four files with different data structures were tested. The week control files (CS) counted with 122,842 controls; the month files (CM), 30,883 controls; the bimestrial (CB) had 15,837 controls and finally the quarterly (CT) had 12,702 controls. It was used the random regression model and, as random, the genetic additive and the animal permanent environmental effects were considered. The covariance function to these two effects was the sixth grade to the genetic effect additive and the seventh grade to the permanent environmental effect, having heterogeneous residual variances, and the residual variance structure was modeled by a "step function". The model had as the fixed effect the contemporaneous groups (GC) commons to all data set, GC were compounded by farm, month, and year of control. The co-variable was the cow age at birth (linear and quadratic regression) and the milking days (fixed regression to the population average). All evaluated data files presented genealogy file composed by 4,380 animals having 1,416 mothers and 228 bulls. The estimate of heritability presented tendencies similar among the analyzed data, having the higher similarity CS, CM and CB. The CT presented small differences in the estimate of heritability when compared to the others. The CB data file presented all the analyzed genetic parameters estimative with the same tendency and magnificence of the CS and CM, allowing the milk control in a CB structure, random regression model in genetic evaluations speaking. The genetic values (VG) to partial milking period production were predicted (MRA100, MRA200, MRA300 e MRA90_305) ...(Complete abstract click electronic access below)
Orientadora: Lucia Galvão de Albuquerque
Coorientadora: Lenira El Faro Zadra
Banca: Danísio Prado Munari
Banca: Humberto Tonhati
Banca: Maria Eugênia Zerlotti Mercadante
Banca: Claudia Cristina Paro de Paz
Doutor
Eliasson, Martin, Khawar Malik, and Benjamin Österlund. "A Value Relevant Fundamental Investment Strategy : The use of weighted fundamental signals to improve predictability." Thesis, Uppsala universitet, Företagsekonomiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-145255.
Full textTorku, Thomas K. "Takens Theorem with Singular Spectrum Analysis Applied to Noisy Time Series." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etd/3013.
Full textDragset, Ingrid Garli. "Analysis of Longitudinal Data with Missing Values. : Methods and Applications in Medical Statistics." Thesis, Norwegian University of Science and Technology, Department of Mathematical Sciences, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9945.
Full textMissing data is a concept used to describe the values that are, for some reason, not observed in datasets. Most standard analysis methods are not feasible for datasets with missing values. The methods handling missing data may result in biased and/or imprecise estimates if methods are not appropriate. It is therefore important to employ suitable methods when analyzing such data. Cardiac surgery is a procedure suitable for patients suffering from different types of heart diseases. It is a physical and psychical demanding surgical operation for the patients, although the mortality rate is low. Health-related quality of life (HRQOL) is a popular and widespread measurement tool to monitor the overall situation of patients undergoing cardiac surgery, especially in elderly patients with naturally limited life expectancies [Gjeilo, 2009]. There has been a growing attention to possible differences between men and women with respect to HRQOL after cardiac surgery. The literature is not consistent regarding this topic. Gjeilo et al. [2008] studied HRQOL in patients before and after cardiac surgery with emphasis on differences between men and women. In the period from September 2004 to September 2005, 534 patients undergoing cardiac surgery at St Olavs Hospital were included in the study. HRQOL were measured by the self-reported questionnaires Short-Form 36 (SF-36) and the Brief Pain Inventory (BPI) before surgery and at six and twelve months follow-up. The SF-36 reflects health-related quality of life measuring eight conceptual domains of health [Loge and Kaasa, 1998]. Some of the patients have not responded to all questions, and there are missing values in the records for about 41% of the patients. Women have more missing values than men at all time points. The statistical analyses performed in Gjeilo et al. [2008] employ the complete-case method, which is the most common method to handle missing data until recent years. The complete-case method discards all subjects with unobserved data prior to the analyses. It makes standard statistical analyses accessible and is the default method to handle missing data in several statistical software packages. The complete-case method gives correct estimates only if data are missing completely at random without any relation to other observed or unobserved measurements. This assumption is seldom met, and violations can result in incorrect estimates and decreased efficiency. The focus of this paper is on improved methods to handle missing values in longitudinal data, that is observations of the same subjects at multiple occasions. Multiple imputation and imputation by expectation maximization are general methods that can be applied with many standard analysis methods and several missing data situations. Regression models can also give correct estimates and are available for longitudinal data. In this paper we present the theory of these approaches and application to the dataset introduced above. The results are compared to the complete-case analyses published in Gjeilo et al. [2008], and the methods are discussed with respect to their properties of handling missing values in this setting. The data of patients undergoing cardiac surgery are analyzed in Gjeilo et al. [2008] with respect to gender differences at each of the measurement occasions; Presurgery, six months, and twelve months after the operation. This is done by a two-sample Student's t-test assuming unequal variances. All patients observed at the relevant occasion is included in the analyses. Repeated measures ANOVA are used to determine gender differences in the evolution of the HRQOL-variables. Only patients with fully observed measurements at all three occasions are included in the ANOVA. The methods of expectation maximization (EM) and multiple imputation (MI) are used to obtain plausible complete datasets including all patients. EM gives a single imputed dataset that can be analyzed similar to the complete-case analysis. MI gives multiple imputed datasets where all dataset must be analyzed sepearately and their estimates combined according to a technique called Rubin's rules. Results of both Student's t-tests and repeated measures ANOVA can be performed by these imputation methods. The repeated measures ANOVA can be expressed as a regression equation that describes the HRQOL-score improvement in time and the variation between subjects. The mixed regression models (MRM) are known to model longitudinal data with non-responses, and can further be extended from the repeated measures ANOVA to fit data more sufficiently. Several MRM are fitted to the data of cardiac surgery patients to display their properties and advantages over ANOVA. These models are alternatives to the imputation analyses when the aim is to determine gender differences in improvement of HRQOL after surgery. The imputation methods and mixed regression models are assumed to handle missing data in an adequate way, and gives similar analysis results for all methods. These results differ from the complete-case method results for some of the HRQOL-variables when examining the gender differences in improvement of HRQOL after surgery.
Chan, Pui-shan, and 陳佩珊. "On the use of multiple imputation in handling missing values in longitudinal studies." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B45009879.
Full textTavares, Nelsilene Mota Carvalho 1971. "Intervalos de referência condicionais de parâmetros dopplervelocimétricos maternofetais = Conditional reference intervals of materno-fetal Doppler parameters." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/311745.
Full textDissertação (Mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: Objetivos: Determinar intervalos de referência condicionais (longitudinais) para os valores de índices de pulsatilidade (IP) nos fluxos da artéria umbilical (AU), cerebral média (ACM), ducto venoso (DV) e IP médio das artérias uterinas (AUT), por meio da avaliação de gestantes de baixo risco de uma amostra da população brasileira. Métodos: Estudo observacional descritivo longitudinal realizado de fevereiro de 2010 a maio de 2012, no Hospital da Mulher Prof. Dr. José Aristodemo Pinotti, Centro de Atenção Integral à Saúde da Mulher, Universidade Estadual de Campinas (CAISM-UNICAMP). Exames ultrassonográficos quinzenais foram realizados para obtenção dos IP das AU, AUT, ACM e IP venoso do DV em gestantes de baixo risco da 18ª a 40ª semana de gravidez. Análise estatística: Modelos lineares mistos foram usados para elaboração de intervalos de referência longitudinais (percentis 5, 50 e 95) dos IP dos vasos mencionados. Variáveis maternas e perinatais foram descritas com o uso de medianas e limites (variáveis contínuas), frequências absolutas e relativas (variáveis categóricas). Os IP das porções placentária e abdominal do cordão umbilical foram comparados por meio do teste T para amostras independentes. Valores de p menores do que 0,05 foram considerados significativos. Resultados: Duzentas e três gestantes de baixo risco foram incluídas no estudo. Cento e sessenta e quatro gestantes concluíram o estudo, sendo realizados 1242 exames ultrassonográficos, com mediana de oito exames por paciente (limites de 4 a 12). Houve redução significativa dos IP de todos os vasos estudados com a idade gestacional (IG). As equações obtidas para predição das medianas foram: IP-AU = 1,5602786 - (0,020623 x IG); Logaritmo do IP-ACM = 0,8149111 - (0,004168 x IG) - [0,002543 x (IG - 28,7756)2]; Logaritmo do IP-DV = 0,26691- (0,015414 x IG); IP-AUt = 1,2362403 - (0,014392 x IG). Houve diferença significativa entre os IP-AU obtidos nas extremidades placentária e abdominal fetal (p < 0,001). Conclusões: Foram estabelecidos intervalos de referência condicionais (longitudinais) dos principais parâmetros dopplervelocimétricos gestacionais em uma amostra da população brasileira. Estes podem ser mais adequados para o acompanhamento das modificações hemodinâmicas maternofetais em gestações normais ou não, a partir de uma validação
Abstract: Purpose: To determine longitudinal reference intervals of pulsatility index (PI) of the umbilical artery (UA), middle cerebral artery (MCA), uterine arteries (UTA) and ductus venosus (DV) in low risk pregnancies of the a Brazilian cohort. Methods: Longitudinal observational study performed from February 2010 to May 2012. Obstetric scans were performed fortnightly for the measurements of the PI of the UA, UTA, MCA, DV in low-risk pregnant women between 18-40 weeks of gestation. Statistical analysis: Linear mixed models were used for the elaboration of longitudinal reference intervals (5th, 50th and 95th centiles) of these measurements. Maternal and perinatal variables were described using median and range (continuous variables), absolute and relative frequencies (categorical variables). The PI obtained at the placental and abdominal portions of the umbilical artery were compared using independent samples T test. P values of less than 0,05 were considered statistically significant. Results: Two hundred and three low-risk pregnancies were included in the study. One hundred sixty four pregnant women completed the study and underwent 1242 scans. There was a significant decrease in the PI values of all studied vessels with gestational age (GA). The equations obtained for the prediction of the medians were as follows: PI-AU = 1,5602786 - (0,020623 x GA); Logarithm of the PI-MCA = 0,8149111 - (0,004168 x GA) - [0,002543 x (GA - 28,7756)2]; Logarithm of the PI-DV = - 0,26691- (0,015414 x GA); PI-UtA = 1,2362403 - (0,014392 x GA). There was a significant difference between the PI-UA obtained at the abdominal and placental ends of the umbilical cord (p < 0,001). Conclusions: Longitudinal reference intervals for the main gestational Doppler parameters were obtained from a Brazilian cohort. These intervals could be more adequate for the follow-up of materno-fetal haemodynamic modifications in normal and abnormal pregnancies, which still requires further validation
Mestrado
Saúde Materna e Perinatal
Mestre em Ciências da Saúde
Fung, David S. "Methods for the estimation of missing values in time series." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2006. https://ro.ecu.edu.au/theses/63.
Full textHubbard, Scott. "A longitudinal study of the theory of parallel growth." Oklahoma City : [s.n.], 2008.
Find full textChevallier, Juliette. "Statistical models and stochastic algorithms for the analysis of longitudinal Riemanian manifold valued data with multiple dynamic." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX059/document.
Full textBeyond transversal studies, temporal evolution of phenomena is a field of growing interest. For the purpose of understanding a phenomenon, it appears more suitable to compare the evolution of its markers over time than to do so at a given stage. The follow-up of neurodegenerative disorders is carried out via the monitoring of cognitive scores over time. The same applies for chemotherapy monitoring: rather than tumors aspect or size, oncologists asses that a given treatment is efficient from the moment it results in a decrease of tumor volume. The study of longitudinal data is not restricted to medical applications and proves successful in various fields of application such as computer vision, automatic detection of facial emotions, social sciences, etc.Mixed effects models have proved their efficiency in the study of longitudinal data sets, especially for medical purposes. Recent works (Schiratti et al., 2015, 2017) allowed the study of complex data, such as anatomical data. The underlying idea is to model the temporal progression of a given phenomenon by continuous trajectories in a space of measurements, which is assumed to be a Riemannian manifold. Then, both a group-representative trajectory and inter-individual variability are estimated. However, these works assume an unidirectional dynamic and fail to encompass situations like multiple sclerosis or chemotherapy monitoring. Indeed, such diseases follow a chronic course, with phases of worsening, stabilization and improvement, inducing changes in the global dynamic.The thesis is devoted to the development of methodological tools and algorithms suited for the analysis of longitudinal data arising from phenomena that undergo multiple dynamics and to apply them to chemotherapy monitoring. We propose a nonlinear mixed effects model which allows to estimate a representative piecewise-geodesic trajectory of the global progression and together with spacial and temporal inter-individual variability. Particular attention is paid to estimation of the correlation between the different phases of the evolution. This model provides a generic and coherent framework for studying longitudinal manifold-valued data.Estimation is formulated as a well-defined maximum a posteriori problem which we prove to be consistent under mild assumptions. Numerically, due to the non-linearity of the proposed model, the estimation of the parameters is performed through a stochastic version of the EM algorithm, namely the Markov chain Monte-Carlo stochastic approximation EM (MCMC-SAEM). The convergence of the SAEM algorithm toward local maxima of the observed likelihood has been proved and its numerical efficiency has been demonstrated. However, despite appealing features, the limit position of this algorithm can strongly depend on its starting position. To cope with this issue, we propose a new version of the SAEM in which we do not sample from the exact distribution in the expectation phase of the procedure. We first prove the convergence of this algorithm toward local maxima of the observed likelihood. Then, with the thought of the simulated annealing, we propose an instantiation of this general procedure to favor convergence toward global maxima: the tempering-SAEM
Lasley, Chandra Y. "Asian Americans: the mediating effects of family on the longitudinal impact of discrimination on self-esteem and wellbeing." Diss., Kansas State University, 2016. http://hdl.handle.net/2097/32531.
Full textFamily Studies and Human Services
Joyce Baptist
The model minority stereotype portrays Asian Americans as resilient, educationally and financially successful, and family-focused, while it downplays the realities of discrimination and its effects on self-esteem. Research suggests that gender roles and immigration experiences are contributing factors to why Asian American women, especially second-generation immigrants, experience greater stress than women of other ethnic groups and Asian American men in general. Considering most Asian Americans are of East and Southeast Asian heritages influenced by Confucian family values and gender roles, this study examined how these values mediated the associated from discrimination to self-esteem during adolescence, and to educational and financial achievement (wellbeing) during adulthood for second-generation immigrants. Using data from the Children of Immigrants Longitudinal Study (N = 554), results from a partially constrained group-comparison model demonstrated that Confucian values of familism and family cohesion were factors that significantly predicted adolescent self-esteem and adult educational achievement. Men’s level of familism endorsement was also uniquely related to experiences with discrimination. Clinical implications and further research directions are discussed.
Fountain, Jason Morgan. "Differences in Generational Work Values in America and Their Implications for Educational Leadership| A Longitudinal Test of Twenge's Model." Thesis, University of Louisiana at Lafayette, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3622936.
Full textThree generations of Americans are currently coexisting in the workforce. One of the primary challenges for educational leaders is to understand the similarities and differences in each generation while also educating a new generation of Americans – today's youth. This longitudinal study used data from the General Social Survey to determine if generational work values differ in accord with the five general categories outlined by Twenge.
Several significant differences emerged. First, Millennials rate higher in work ethic over Boomers and GenXers. Additionally, a linear decline from Boomers to Millennials was found in intrinsic values, while Millennials were found to have the highest need for extrinsic values. Finally, a linear decline from Boomers to GenXers to Millennials was evident in relation to social values in the work setting.
The primary implication from this study involves the contradictory nature of Millennials. While they have the highest work ethic, they also rate highest in leisure values and the need for extrinsic values. Further research should be conducted to isolate values pertinent to teachers and a cross-sectional study should be conducted to determine value differences of the current workforce.
Ferreira, Sabrina Girotto 1978. "Idade gestacional e dopplervelocimetria fetoplacentária e úteroplacentária em relação ao grau placentário de grannum em gestações de baixo risco = estudo longitudinal = Gestational age and fetomaternal doppler parameters according to placenta grannum grading in low-risk pregnancies : a longitudinal study." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/308764.
Full textDissertação (Mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
Made available in DSpace on 2018-08-20T20:27:17Z (GMT). No. of bitstreams: 1 Ferreira_SabrinaGirotto_M.pdf: 3220177 bytes, checksum: fc5df188c73f1cc85083481b3efdcf1b (MD5) Previous issue date: 2012
Resumo: Objetivo: Estabelecer intervalos de referência de idade gestacional (IG), índices de pulsatilidade (IP) das artérias umbilical (AU) e média das artérias uterinas (AUT) de acordo com o grau placentário de Grannum. Esses dados servirão como base para estudo em andamento que avalia o impacto do amadurecimento precoce da placenta nos parâmetros dopplervelocimétricos acima mencionados e os resultados perinatais. Sujeitos e métodos: estudo prospectivo longitudinal observacional realizado em hospital universitário terciário, em que 133 gestações de baixo risco foram avaliadas quinzenalmente pela USG, entre 18 e 41 semanas. A classificação placentária de Grannum et al. (1), IP-AU e IPm-AUT foram obtidos em cada exame. Os intervalos de referência (mediana, 5?, 10?, 90? e 95? percentil) de IG, IP-AU e IPm-AUT foram estabelecidos para cada grau placentário. Testes de Mann-Whitney com correção de Bonferroni foram utilizados para comparar os parâmetros acima mencionados entre dois diferentes graus placentários. O valor de p bicaudal menor que 0,05 foi considerado estatisticamente significativo. Resultados: A IG aumentou significativamente com a mudança do grau placentário. IP-AU e IP-AUT reduziram significativamente do grau zero para o um e do grau um para o dois, mas permaneceram estáveis depois disso. Conclusões: Os intervalos de referência dos parâmetros dopplervelocimétricos que refletem implantação normal e função placentária foram elaborados como um primeiro passo que permitirá comparar e testar nossos dados com as publicações existentes para a predição de resultados perinatais em casos de amadurecimento precoce da placenta em gestações de baixo risco
Abstract: Objective: To establish reference intervals of gestational age (GA), umbilical artery (UmbA) and mean uterine artery (mUtA) Doppler pulsatility indexes (PI) according to placental grade. This will serve as a basis for an ongoing study aimed at evaluating the impact of early placental ageing and the abovementioned Doppler parameters on pregnancy outcomes. Materials and Methods: Longitudinal observational study realized in tertiary university hospital where 133 low-risk pregnancies were scanned fortnightly from 18 to 41 weeks. Placental classification according to Grannum et al. (1), UmbA-PI and and mUtA-PI were obtained in each scan. Reference intervals (median, 5th, 10th, 90th and 95th centiles) of GA, UmbA-PI and mUtA-PI were established for each placental grade. Mann-Whitney U tests with Bonferroni adjustments were used to compare these parameters between two different placental grades. Two-tailed p-values of less than 0.05 were considered statistically significant. Results: GA significantly increased as placental grade changed. UmbA-PI and mUtA-PI significantly decreased between grades zero and one and between grades one and two, but remained stable between grades two and three. Conclusions: Reference intervals of GA and Doppler parameters which reflect normal implantation and function of the placenta were elaborated as a first step to allow further testing and comparison of our data with those previously published for the prediction of pregnancy outcomes in cases of suspicion of an early placental ageing is suspected
Mestrado
Saúde Materna e Perinatal
Mestre em Ciências da Saúde
Loker, Troy. "Character strengths and virtues of young internationally adopted Chinese children : a longitudinal study from preschool to school age." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0003270.
Full textMoreno, Betancur Margarita. "Regression modeling with missing outcomes : competing risks and longitudinal data." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA11T076/document.
Full textMissing data are a common occurrence in medical studies. In regression modeling, missing outcomes limit our capability to draw inferences about the covariate effects of medical interest, which are those describing the distribution of the entire set of planned outcomes. In addition to losing precision, the validity of any method used to draw inferences from the observed data will require that some assumption about the mechanism leading to missing outcomes holds. Rubin (1976, Biometrika, 63:581-592) called the missingness mechanism MAR (for “missing at random”) if the probability of an outcome being missing does not depend on missing outcomes when conditioning on the observed data, and MNAR (for “missing not at random”) otherwise. This distinction has important implications regarding the modeling requirements to draw valid inferences from the available data, but generally it is not possible to assess from these data whether the missingness mechanism is MAR or MNAR. Hence, sensitivity analyses should be routinely performed to assess the robustness of inferences to assumptions about the missingness mechanism. In the field of incomplete multivariate data, in which the outcomes are gathered in a vector for which some components may be missing, MAR methods are widely available and increasingly used, and several MNAR modeling strategies have also been proposed. On the other hand, although some sensitivity analysis methodology has been developed, this is still an active area of research. The first aim of this dissertation was to develop a sensitivity analysis approach for continuous longitudinal data with drop-outs, that is, continuous outcomes that are ordered in time and completely observed for each individual up to a certain time-point, at which the individual drops-out so that all the subsequent outcomes are missing. The proposed approach consists in assessing the inferences obtained across a family of MNAR pattern-mixture models indexed by a so-called sensitivity parameter that quantifies the departure from MAR. The approach was prompted by a randomized clinical trial investigating the benefits of a treatment for sleep-maintenance insomnia, from which 22% of the individuals had dropped-out before the study end. The second aim was to build on the existing theory for incomplete multivariate data to develop methods for competing risks data with missing causes of failure. The competing risks model is an extension of the standard survival analysis model in which failures from different causes are distinguished. Strategies for modeling competing risks functionals, such as the cause-specific hazards (CSH) and the cumulative incidence function (CIF), generally assume that the cause of failure is known for all patients, but this is not always the case. Some methods for regression with missing causes under the MAR assumption have already been proposed, especially for semi-parametric modeling of the CSH. But other useful models have received little attention, and MNAR modeling and sensitivity analysis approaches have never been considered in this setting. We propose a general framework for semi-parametric regression modeling of the CIF under MAR using inverse probability weighting and multiple imputation ideas. Also under MAR, we propose a direct likelihood approach for parametric regression modeling of the CSH and the CIF. Furthermore, we consider MNAR pattern-mixture models in the context of sensitivity analyses. In the competing risks literature, a starting point for methodological developments for handling missing causes was a stage II breast cancer randomized clinical trial in which 23% of the deceased women had missing cause of death. We use these data to illustrate the practical value of the proposed approaches
Ochoa, Banafsheh K. "Maxillary growth in comparison to mandibular growth." Oklahoma City : [s.n.], 2002. http://library.ouhsc.edu/epub/theses/Ochoa-Banafsheh-K.pdf.
Full textIgnell, Caroline. "Exploring changes of conceptions, values and beliefs concerning the environment : A longitudinal study of upper secondary school students in business and economics education." Doctoral thesis, Stockholms universitet, Institutionen för pedagogik och didaktik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-147639.
Full textAt the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 3: Manuscript.
Sakamoto, Kathia. "Construção de curvas de normalidade dos índices dopplervelocimétricos das circulações uteroplacentária, fetoplacentária e fetal." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/5/5139/tde-01062007-122759/.
Full textINTRODUCTION: The Doppler velocimetry is a non-invasive method that allows the evaluation of the placental function and the fetal response to hypoxia in high-risk pregnancies. Many publications have presented the Doppler velocimetric indices reference ranges of the vessels. However, the oldest ones used inferior Doppler ultrasound technology when compared to what is currently available. Others have shown flaws in the methods size and selection of the samples, number of exams performed, the use of inappropriate statistical method to analyze the obtained data. OBJECTIVE: The purpose of this study is to construct the normal Doppler velocimetric indices reference ranges of the uteroplacental (maternal right and left uterine arteries - UAT), fetoplacental (umbilical arteries - UA) and fetal (middle cerebral artery - MCA, descendent thoracic aorta - DTA, ductus venosus - DV) circulations. Prospective and longitudinal data was obtained from normal pregnancies from 14 to 42 gestational weeks with normal delivery and neonatal outcomes. METHODS: Pregnant women were recruited from low-risk prenatal care units, and examined in the Fetal Surveillance Unit at the Obstetric Clinic (Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, SP, Brazil), between April 2000 and May 2004. Two-hundred ninety-four patients were recruited and 154 qualified to be part of the sample. A total of 908 Doppler velocimetric evaluations were performed by the same operator with a success rate of greater than 94% for each vessel studied, using ultrasound equipment with pulsatile Doppler and real-time color flow mapping technology. Random effects or multilevel models described by Royston (1995) were used in the analysis of the data obtained. The indices and the gestational age (in weeks) were tested for normal distribution by using fitted models and fractional polynomials transformation, respectively. When the transformed data did not show improvement in the normal distribution, the original values were used. RESULTS: The conditional and unconditional reference intervals for the 90% confidence interval were obtained for the indices of each vessel. Since the comparison between the unconditional and conditional reference intervals curves were very similar, the curves of the unconditional reference intervals were presented as they showed smoothed lines. CONCLUSION: The normal reference ranges of the Doppler velocimetric indices S/D ration, pulsatility index (PI) and resistance index (RI) of the UAT, UA, fetal MCA and DTA; and the S/a ratio, pulsatility index for veins (IPV) and DV index (IDV) of the DV were obtained from normal pregnancies between 14 and 42 weeks\' gestation, in a prospective and longitudinal study of the Brazilian population.
Salmeh, Louay. "L'abandon sportif : des motifs d'abandon aux modèles théoriques : une recherche longitudinale chez les handballeuses et les basketteuses." Phd thesis, Université de Bourgogne, 2011. http://tel.archives-ouvertes.fr/tel-00661589.
Full textAyvazyan, Vigen. "Etude de champs de température séparables avec une double décomposition en valeurs singulières : quelques applications à la caractérisation des propriétés thermophysiques des matérieux et au contrôle non destructif." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14671/document.
Full textInfrared thermography is a widely used method for characterization of thermophysical properties of materials. The advent of the laser diodes, which are handy, inexpensive, with a broad spectrum of characteristics, extend metrological possibilities of infrared cameras and provide a combination of new powerful tools for thermal characterization and non destructive evaluation. However, this new dynamic has also brought numerous difficulties that must be overcome, such as high volume noisy data processing and low sensitivity to estimated parameters of such data. This requires revisiting the existing methods of signal processing, adopting new sophisticated mathematical tools for data compression and processing of relevant information.New strategies consist in using orthogonal transforms of the signal as a prior data compression tools, which allow noise reduction and control over it. Correlation analysis, based on the local cerrelation study between partial derivatives of the experimental signal, completes these new strategies. A theoretical analogy in Fourier space has been performed in order to better understand the «physical» meaning of modal approaches.The response to the instantaneous point source of heat, has been revisited both numerically and experimentally. By using separable temperature fields, a new inversion technique based on a double singular value decomposition of experimental signal has been introduced. In comparison with previous methods, it takes into account two or three-dimensional heat diffusion and therefore offers a better exploitation of the spatial content of infrared images. Numerical and experimental examples have allowed us to validate in the first approach our new estimation method of longitudinal thermal diffusivities. Non destructive testing applications based on the new technique have also been introduced.An old issue, which consists in determining the initial temperature field from noisy data, has been approached in a new light. The necessity to know the thermal diffusivities of an orthotropic medium and the need to take into account often three-dimensional heat transfer, are complicated issues. The implementation of the double singular value decomposition allowed us to achieve interesting results according to its ease of use. Indeed, modal approaches are statistical methods based on high volume data processing, supposedly robust as to the measurement noise
Audulv, Åsa. "Being creative and resourceful : Individuals’ abilities and possibilities for self-management of chronic illness." Doctoral thesis, Mittuniversitetet, Institutionen för hälsovetenskap, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-13512.
Full textExploring individuals’ conceptions as a way to understand self-management among people living with long term medical conditions
Jakobsson, Anton. "Prognostic value of global longitudinal strain in patients with myocardial infarction and normal LVEF." Thesis, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-380395.
Full textCampbell, Paul. "Analysing and understanding changes in "fixed" characteristics over time: The value of longitudinal data." Phd thesis, 2022. http://hdl.handle.net/1885/274331.
Full textGerardo, Bianca Salguinho. "Visuoconstructional impairment in Mild Cognitive Impairment: Diagnostic utility and predictive value in the progression to Alzheimer’s disease." Master's thesis, 2018. http://hdl.handle.net/10316/85593.
Full textIntrodução: A visuoconstrução é um domínio cognitivo que se define pela capacidade de organizar e manipular manualmente informações espaciais, por forma criar um design ou copiar um modelo. Este é um domínio complexo que integra processos como a visuoperceção, a análise visuospacial, as capacidades motoras finas, a atenção e várias funções executivas. Na doença de Alzheimer (DA) a visuoconstrução é frequentemente avaliada através de provas de desenho por cópia ou de desenho livre. Tendo em conta a complexidade da visuoconstrução, e considerando o comprometimento de diversas áreas cerebrais implicado na DA, é possível observar-se défices visuoconstrutivos desde as fases iniciais da doença.Objetivos: (1) Avaliar os défices visuoconstrutivos no Defeito Cognitivo Ligeiro (DCL) e estudar as diferenças entre doentes com DCL amnésico (DCLa) e DCL amnésico multidomínios (DCLam); (2) avaliar o valor do domínio visuoconstrutivo como preditor da conversão para DA.Métodos: Cento e oitenta e quatro doentes diagnosticados com DCLa (n=121) e DCLam (n=63) foram avaliados anualmente (entre 2 a 11 anos) em contexto de consulta de demência ao nível da sua cognição, funcionalidade e psicopatologia, através de uma extensiva bateria neuropsicológica. A avaliação da visuoconstrução foi realizada através das seguintes tarefas: o Teste do Desenho dos Pentágonos (TDP), o Teste da Cópia do Cubo (TCC), a Tarefa de Praxia Construtiva (TPC) e a condição de desenho livre do Teste de Desenho do Relógio (TDR). O domínio visuospacial do Montreal Cognitive Assessment (MoCA) foi igualmente utilizado como medida visuoconstrutiva.Resultados: Os doentes diagnosticados com DCLam apresentaram piores capacidades visuoconstrutivas que os doentes com DCLa. Apesar de as diferenças entre os dois grupos terem sido detetadas tanto em tarefas de cópia como em tarefas de desenho livre, as tarefas de cópia menos complexas (TDP e os dois itens mais simples da TPC) não reportaram diferenças estatisticamente significativas (p>.05). Em relação às diferenças entre os doentes que converteram (C) e aqueles que não converteram (NC) para demência, observou-se uma inclusão significativamente maior de doentes com inícios tardios da doença no grupo C (t(135.66)= -4.233, p<.001). As análises de sobrevivência acusaram taxas de conversão significativamente diferentes para doentes com inícios precoces (IP) e para doentes com inícios tardios (IT) da doença (χ2(1)=13.416, p<.001), com estes últimos a apresentarem sistematicamente menores probabilidades de permanecerem estáveis. As análises multinível dos doentes IP acusaram o TDR (χ2(1)=5.019, p=.025) e o efeito de interação ente o TDP e o Tempo (χ2(1)=6.655, p=.010) como preditores significativos da demência. Para os doentes IT, os preditores revelados foram o TDR (χ2(1)=16.677, p<.001) e o domínio visuospacial do MoCA (χ2(1)=4.157, p=.041). Em ambos os modelos, piores pontuações nas tarefas de desenho implicaram um aumento da probabilidade de converter relativamente à probabilidade de não converter para demência.Conclusões: Os resultados sugerem um comprometimento visuoconstrutivo mais acentuado nos doentes com DCLam comparativamente aos doentes com DCLa. Adicionalmente, a visuoconstrução parece constituir-se como preditor significativo da DA, com maiores défices nesta capacidade a traduzirem um incremento na probabilidade de progredir de uma condição de DCL para demência. Uma vez que os doentes com inícios tardios da doença apresentam menores probabilidades de permanecerem estáveis comparativamente aos seus homólogos com inícios precoces, doentes com inícios tardios e fracas capacidades visuoconstrutivas puderão constituir um grupo em elevado risco de conversão. Neste sentido, os défices visuoconstrutivos poderão ser utilizados como importantes sinais de aviso da probabilidade de conversão de um doente.
Introduction: Visuoconstruction is a cognitive domain that can be defined as the ability to organize and manually manipulate spatial information in order to create a design or copy a model. As a complex domain, visuoconstruction requires the interaction of different processes, such as visuoperception, visuospatial analysis, fine motor skills, attention and executive functions. In Alzheimer’s disease (AD), this domain is frequently assessed through drawing tasks, including both copying and drawing-to-command. Given the complexity of this capacity, and since AD involves the impairment of several brain areas, visuoconstruction can be compromised in the early stages of the disease.Objectives: (1) To assess visuoconstructional impairments in Mild Cognitive Impairment (MCI) and study differences between amnestic single-domain MCI (aMCI) and amnestic multidomain MCI (amMCI) patients; (2) to assess the value of visuoconstruction as a predictor of AD.Methodology: One-hundred and eighty four patients diagnosed with aMCI (n=121) and amMCI (n=63) were followed in dementia consultation an evaluated annually through an extensive neuropsychological battery. All patients were assessed at a cognitive, functional and psychopathological level. To assess visuoconstruction, we applied the following tasks: the Pentagon Drawing Test (PDT), the Cube Copying Test (CCT), the Constructional Praxis Task (CPT) and the drawing-to-command condition of the Clock Drawing Test (CDT). The visuospatial domain of Montreal Cognitive Assessment (MoCA) was also used as a measure of visuoconstruction.Results: Overall, amMCI patients presented worst visuoconstructional abilities than aMCI patients. Although these differences were detected either by copying or drawing-to-command tasks, less complex copying tasks (PDT and the two simpler items of the CPT) could not distinguish the two groups (p>.05). Regarding the differences between patients who converted (C) and patients who did not convert (NC) to dementia, the C group included significantly more MCI patients with late-onsets than the NC group (t(135.66)= -4.233, p<.001). Survival analysis reported significantly different patterns of conversion for patients with early-onsets (EO) and late-onsets (LO) (χ2(1)=13.416, p<.001), with the latter presenting lower probabilities of remaining stable. Multilevel analysis of EO patients yelled the CDT (χ2(1)=5.019, p=.025) and the interaction effect between the PDT and Time (χ2(1)=6.655, p=.010) as significant predictors of dementia. For LO patients, the yelled predictors were the CDT (χ2(1)=16.677, p<.001) and the visuospatial domain of MoCA (χ2(1)=4.157, p=.041). In both models, worse visuoconstructional scores implied an increase in the chances of a patient converting versus the chances of not converting.Conclusions: Our results suggest that amMCI patients present steeper visuoconstructional impairment in comparison to aMCI patients. Besides, visuoconstruction is a significant predictor of AD, with greater deficits leading to an increase in the probability to convert from MCI to dementia. Since late-onset patients are less likely to remain stable compared to their early-onset counterparts, late-onset patients with poor visuoconstructive capabilities may constitute a group at high risk of conversion. In this sense, visuoconstructive deficits may be used as an important warning sign of the probability of a patient to develop dementia.
Pestana, Carolina Alexandre Festas Gomes. "Study of biomarkers in Multiple Myeloma: a statistical approach for longitudinal assessment of extracellular vesicles and its prognostic value." Master's thesis, 2021. http://hdl.handle.net/10451/49084.
Full textO Mieloma Múltiplo (MM) é um cancro hematológico que tem origem na proliferação de células plasmáticas clonais que se acumulam na medula óssea e segregam imunoglobulinas monoclonais (mIg). Esta proliferação é acompanhada pela diminuição da função da medula óssea e pela destruição do tecido ósseo (Mangan, 2005). O MM é quase sempre precedido por dois estádios de doenças: MGUS (Monoclonal Gammopathy of Undetermined Significance) e de um estádio intermédio/indolente denominado SMM (Smoldering Multiple Myeloma). Nestes estádios, nenhuma das características que definem o MM está presente e os doentes requerem apenas vigilância médica periódica (Ho et al., 2020). Na maior parte dos casos, o doente é diagnosticado a partir de análises laboratoriais, uma vez que os sintomas só começam a surgir numa fase mais tardia. No entanto, o diagnóstico final é realizado através de aspiração e biópsia de medula óssea. Estes testes, apesar de invasivos, são considerados gold standard para o diagnóstico, uma vez que permitem a quantificação dos plasmócitos clonais na medula óssea. Contudo, não existe ainda na prática clínica outro teste disponível que seja menos agressivo e que o substitua. Atualmente, o Revised International Staging System (R-ISS) (Palumbo et al., 2015) é o modelo usado como base para a determinação do prognóstico de doentes MM recentemente diagnosticados, correspondendo a um score de agressividade de doença. Através de uma escala de três níveis, este modelo de estratificação de risco determina quais os doentes com melhor prognóstico, intermédio e pior. Apesar dos constantes avanços a que se assiste no campo do MM, doentes que aparentemente têm prognósticos semelhantes acabam por apresentar desfechos bastante heterógeneos. Isto indica que os mecanismos atuais, embora úteis, falham na determinação de um prognóstico preciso. De forma a encontrar novos biomarcadores séricos desta doença que permitam um acompanhamento constante do prognóstico do doente de forma menos invasiva, têm sido estudados novos métodos utilizando biópsias líquidas (Ferreira et al., 2020). Este tipo de biópsia permite obter informação sobre a doença a partir de amostras sanguíneas utilizando uma técnica minimamente invasiva. É neste contexto que surge o estudo de vesículas extracelulares, em particular de exosomas. Os exosomas são partículas com um diâmetro entre 30 e 100 nanómetros, produzidos por vários tipos de células e secretadas por estas para o microambiente extracelular. Sabe-se que têm várias funções e estão envolvidos em diversos processos celulares, alguns patológicos, como a transformação de células saudáveis em células malignas, bem como na indução do nicho pré-metastático (Kawano et al., 2015). Existem já vários estudos que demonstram que os exosomas isolados a partir do sangue periférico de doentes com MM podem servir como marcadores de diagnóstico e predição de progressão de doença, uma vez que os exosomas refletem a grande parte das propriedades das células que lhes deram origem (Moloudizargari et al., 2019); neste caso, das células tumorais. Neste estudo, cuja mediana do tempo de observação ronda os 2 anos, foram sendo colhidas prospectivamente amostras de 102 doentes diagnosticados e/ou tratados no centro clínico da Fundação Champalimaud (Lisboa, Portugal) que foram diagnosticados à entrada no estudo com MM ou outra gamapatia monoclonal (MGUS ou SMM). O objetivo principal deste estudo foi a validação das vesículas extracelulares, não só enquanto biomarcador de prognóstico, mas também enquanto mecanismo de monitorização e acompanhamento regular dos doentes na prática clínica. A avaliação destas vesículas extracelulares foi desenvolvida por intermédio da variável EVs Cargo (Extracellular Vesicles Cargo). Esta variável corresponde ao rácio entre a concentração proteica e a concentração das partículas (μg/108 partículas) e, até agora, nunca antes tinha sido estudada neste âmbito, uma vez que habitualmente representa apenas uma medida de pureza, demonstrando a eficiência dos protocolos de isolamento. As variáveis de interesse incluíram variáveis demográficas tais como a idade, o género, o diagnóstico à entrada no estudo, os scores de agressividade de doença (para MGUS, SMM e MM), a sequência cronológica em que as amostras foram colhidas, bem como o número de linhas de tratamento previamente realizadas em cada colheita de amostra, mas também variáveis laboratoriais, tais como os níveis de IgG, IgA e IgM, os níveis de sFLC kappa e lambda, o nível do rácio sFLC, bem como os níveis de LDH, hemoglobina, neutrófilos, plaquetas, beta-2-microglobulina, creatinina, albumina e proteína-C reactiva. Estas variáveis foram selecionadas tendo em conta o seu impacto e relevância clínica, de acordo com a literatura existente. A sobrevivência global foi definida como o tempo, em meses, desde a entrada no estudo até morte por qualquer causa. Doentes que não manifestavam o outcome de interesse à data do último follow-up conhecido foram censurados nessa data. Numa fase inicial, através das estimativas de Kaplan-Meier das funções de sobrevivência global, foi possível verificar que, à entrada no estudo, a coorte estudada assume as mesmas características das já demonstradas e verificadas pela literatura. Nomeadamente, foi possível observar que doentes MGUS apresentam uma probabilidade de sobrevivência superior a doentes SMM e MM, e que doentes SMM apresentam uma probabilidade de sobrevivência superior a MM. Contudo, aproximadamente a partir da mediana do tempo de estudo, doentes SMM revelam pior sobrevivência do que doentes MM. Por outro lado, focando-nos nos doentes MM, verificou-se que, não só existem diferenças relativamente à sobrevivência global dos doentes consoante o nível R-ISS, mas também que o prognóstico piora progressivamente ao longo da escala R-ISS (Palumbo et al., 2015). Finalmente, foi também observado que os doentes que, à entrada no estudo, tivessem já realizado alguma linha de tratamento, apresentam pior prognóstico, sendo que este piora com o aumento do número de linhas de tratamento. Esta observação é concordante com o publicado por Kumar et al. (2004). Na primeira fase deste projeto foi testada a associação da variável de interesse (EVs Cargo) com a sobrevivência global dos doentes, à altura da inclusão no estudo. Contudo, face à não validação dos pressupostos necessários à aplicação de modelos de regressão de Cox, esta variável foi categorizada tendo como base uma metodologia direcionada especificamente para o outcome pretendido: neste caso, a sobrevivência global. Através desta metodologia, foi possível obter um ponto de corte ótimo, que nos permitiu categorizar a variável EVs Cargo em dois grupos: EVs Cargo Low (≤ 0.6 μg/108 partículas) e EVs Cargo High (> 0.6 μg/108 partículas), com uma diferença significativa entre estes dois grupos relativamente à sobrevivência global. De forma interessante, através das estimativas de Kaplan-Meier das funções de sobrevivência global foi também possível observar que, apesar de doentes MM (independentemente do nível EVs Cargo) apresentarem sempre pior prognóstico do que doentes SMM, com o passar do tempo, doentes SMM com EVs Cargo High passam a apresentar pior prognóstico do que qualquer uma das categorias de MM. Este resultado pode ser indicador da necessidade de tratamento de doentes SMM de alto risco: devido ao facto destes doentes não serem tratados, doentes SMM de risco elevado acabam por apresentar, ao longo do tempo, um pior prognóstico do que doentes MM, para qualquer um dos níveis de EVs Cargo. Em seguida, tendo em conta a estratificação da variável EVs Cargo, foi desenvolvido um modelo longitudinal que nos permitiu avaliar a significância de alguns fatores na explicação de doentes que, ao longo do tempo, manifestam EVs Cargo High. O que se observou foi que os doentes que ao longo do tempo manifestam níveis reduzidos de IgA bem como níveis elevados de sFLC lambda e um reduzido tempo em resposta (caracterizado pelo tempo entre linhas de tratamento) são doentes que têm maiores chances de apresentar EVs Cargo High e, em consequência, um pior prognóstico. A qualidade do ajustamento do modelo proposto foi verificada pela curva ROC e pela respetiva AUC. Por último, e através da análise diferencial da expressão proteica entre os diversos níveis das variáveis selecionadas como significativas no modelo proposto, foi possível validar os resultados e conclusões obtidos pelo modelo. Para a validação final enquanto biomarcador de prognóstico, foi feita também a comparação entre doentes e dadores saudáveis ao nível da expressão proteica. Esta foi a primeira vez que vesículas extracelulares provenientes de doentes com gamapatias monoclonais foram analisadas usando um estudo clínico observacional, no qual a evolução natural da doença foi sendo seguida ao longo do tempo. Através deste estudo foi possível verificar que, não só as vesículas extracelulares têm potencial para serem usadas como biomarcadores no contexto do MM, como também que a variável EVs Cargo em particular reúne todas as condições para que possa ser usada enquanto variável de prognóstico e como mecanismo de avaliação periódica dos doentes. A utilização desta variável enquanto biomarcador nunca antes tinha sido testada. Embora estes resultados careçam de validação numa coorte maior, seguida durante mais tempo, creio que as conclusões obtidas com este estudo têm uma enorme relevância translacional e que podem, futuramente, constituir uma forma de prognóstico e acompanhamento constante das alterações no estado clínico dos doentes.
Over the years there have been significant improvements in the oncological field. We are currently moving towards a more patient-oriented medicine, aiming at constant monitoring and follow-up of the evolution of each patient’s condition. In the particular case of MM, we know that patients with similar prognoses may present heterogeneous outcomes. This indicates that the current prognostic mechanisms, although useful, are not sufficiently precise. In this sense, the study of extracellular vesicles emerges as a prognostic and follow-up mechanism of patients. In this project, based on a total of 102 patients monitored over a median period of, approximately, 2 years and using the variable EVs Cargo (protein:particle ratio) as representative of extracellular vesicles, we could prove that, at study entry, patients presenting EVs Cargo > 0.6 μg/108 particles (high risk) have a significantly worse prognosis than patients with EVs Cargo ≤ 0.6 μg/108 particles (low risk). Furthermore, it was possible to observe that high-risk SMM patients have, over time, a worse prognosis than low-risk MM patients and, to some extent, even worse than high-risk MM patients. On the other hand, and taking into account the established cut-off, it was possible to verify that patients who, over time, manifest a depletion of IgA levels, high levels of sFLC lambda and a short time in response have increased odds of presenting high levels of EVs Cargo and, consequently, a worse prognosis. The quality of the adjustment of the model was verified by the ROC curve and the AUC measurement. Furthermore, the validity of the results obtained was verified by the analysis of differential protein expression between the levels of the variables included in the model, but also by protein comparison between healthy donors and patients. Through this complete approach, it was possible not only to validate the EVs Cargo as a prognostic biomarker but also as a follow-up mechanism of patients throughout the natural course of their disease. Further studies with a longer follow-up period and a different cohort of patients are needed to confirm our results. If these results are validated, this could be a new tool to be used as the first alarm signal of the deterioration of the patient’s health condition, allowing more thorough examinations in such cases.
Kundu, Madan Gopal. "Advanced Modeling of Longitudinal Spectroscopy Data." Thesis, 2014. http://hdl.handle.net/1805/5454.
Full textMagnetic resonance (MR) spectroscopy is a neuroimaging technique. It is widely used to quantify the concentration of important metabolites in a brain tissue. Imbalance in concentration of brain metabolites has been found to be associated with development of neurological impairment. There has been increasing trend of using MR spectroscopy as a diagnosis tool for neurological disorders. We established statistical methodology to analyze data obtained from the MR spectroscopy in the context of the HIV associated neurological disorder. First, we have developed novel methodology to study the association of marker of neurological disorder with MR spectrum from brain and how this association evolves with time. The entire problem fits into the framework of scalar-on-function regression model with individual spectrum being the functional predictor. We have extended one of the existing cross-sectional scalar-on-function regression techniques to longitudinal set-up. Advantage of proposed method includes: 1) ability to model flexible time-varying association between response and functional predictor and (2) ability to incorporate prior information. Second part of research attempts to study the influence of the clinical and demographic factors on the progression of brain metabolites over time. In order to understand the influence of these factors in fully non-parametric way, we proposed LongCART algorithm to construct regression tree with longitudinal data. Such a regression tree helps to identify smaller subpopulations (characterized by baseline factors) with differential longitudinal profile and hence helps us to identify influence of baseline factors. Advantage of LongCART algorithm includes: (1) it maintains of type-I error in determining best split, (2) substantially reduces computation time and (2) applicable even observations are taken at subject-specific time-points. Finally, we carried out an in-depth analysis of longitudinal changes in the brain metabolite concentrations in three brain regions, namely, white matter, gray matter and basal ganglia in chronically infected HIV patients enrolled in HIV Neuroimaging Consortium study. We studied the influence of important baseline factors (clinical and demographic) on these longitudinal profiles of brain metabolites using LongCART algorithm in order to identify subgroup of patients at higher risk of neurological impairment.
Partial research support was provided by the National Institutes of Health grants U01-MH083545, R01-CA126205 and U01-CA086368
Nelson, Dean E. "A simulation study of the hierarchical linear model with serially correlated longitudinal data and missing values /." Diss., 1999. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9935173.
Full textAlmeida, Ana Isabel Silva. "On the work values of entrepreneurs and non-entrepreneurs: A european longitudinal study." Master's thesis, 2014. https://repositorio-aberto.up.pt/handle/10216/75941.
Full textPorfeli, Erik J. "A longitudinal study of a developmental-centextual model of work values during adolescence." 2004. http://www.etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-578/index.html.
Full textAlmeida, Ana Isabel Silva. "On the work values of entrepreneurs and non-entrepreneurs: A european longitudinal study." Dissertação, 2014. https://repositorio-aberto.up.pt/handle/10216/75941.
Full text"Changing consumption values in urban China: a longitudinal study of newspaper advertising, 1981-2003." 2004. http://library.cuhk.edu.hk/record=b5891941.
Full textThesis (M.Phil.)--Chinese University of Hong Kong, 2004.
Includes bibliographical references (leaves 106-113).
Abstracts in English and Chinese.
Chapter Chapter 1 --- Introduction --- p.1
Chapter Chapter 2 --- Literature Review --- p.4
Consumption in a modern world --- p.4
Modernization and consumption values --- p.10
Chapter Chapter 3 --- Modernization in Urban China since 1979 and Research Hypotheses and Question --- p.20
Modernization in urban China --- p.20
Previous findings on consumption values in China --- p.28
Research hypotheses and question --- p.33
Chapter Chapter 4 --- Research Methods --- p.35
Content analysis of newspaper ads --- p.35
Interviews with experienced advertising professionals --- p.51
Chapter Chapter 5 --- Research Findings --- p.54
Consumption values manifested in newspaper advertising --- p.54
The findings from interviews: changing consumption values in urban China corresponds to modernization --- p.77
Chapter Chapter 6 --- Conclusion and Discussion --- p.87
Concluding remarks --- p.87
Limitations and suggestions for future research --- p.91
Appendix --- p.94
Basic questions for in-depth interviews with advertising professionals --- p.94
Salience trends of consumption values found in newspaper ads --- p.95
References --- p.106
HUANG, YAN-LING, and 黃彥菱. "Analysis of Longitudinal Data with Censored and Missing Values via Nonlinear Mixed-effects Models." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/23267683758841290881.
Full text逢甲大學
統計學系
105
Repeated measures from clinical trials or biomedical research are usually collected and shown to be nonlinear profiles, the nonlinear mixed-effects model (NLMM) has become a popular modelling tool for analyzing such kind of data. However, censored and missing data often occur in longitudinal studies due to limitations of the measuring technology, missed visits, loss to follow-up, and so on. This thesis formulates the nonlinear mixed-effects model with censored and missing responses (NLMM-CM), which allows the analysts to model longitudinal data in the presence of censored and missing values simultaneously. The nonlinear mixed-effects model with censored values (NLMM-C), nonlinear mixed-effects model with missing values (NLMM-M) and nonlinear mixed-effects model (NLMM), which are treated as special cases of the NLMM-CM, are also presented and compared to the proposed NLMM-CM in simulation sudies. To carry out maximum likelihood estimation of model parameters, we provide an efficient expectation conditional maximization (ECM) algorithm. This method is developed under the complete pseudo-data likelihood function, which is derived by using first-order Taylor expansion around individual-specific parameters. Real-data examples and simulation studies are used to demonstrate the performance of our proposed methods.
Carrillo, Garcia Ivan Adolfo. "Analysis of Longitudinal Surveys with Missing Responses." Thesis, 2008. http://hdl.handle.net/10012/3971.
Full textLUO, CHUN-CHIUNG, and 羅鈞瓊. "The longitudinal research in the effect of working values on salary performance of Taiwan youths." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/k48mw3.
Full text輔仁大學
企業管理學系管理學碩士在職專班
105
In recent years, Taiwan has been faced with changes in industrial environment and the problem of low birth rate. Thus, in terms of human resource management, enterprise also needs to consider how to manage the new-generation young personnel and retain the outstanding talents. This research aims to discuss the effect of youth’s (aged 16 to 24) working values on their salary level in different time points when they are more than 25 years old. This research adopted the longitudinal tracing investigation data of “Panel Study of Family Dynamics” in Humanities and Social Sciences Research Center, Academia Sinica collected from 1999 to 2014 in Taiwan. In this research, 9,291 samples were used and there were 643 investigated samples in 9 time intervals of all databases, but only 92 samples had the common intersection in the 2 types of data. The research results show that both environmental and self working values can positively predict salary level. In group comparison, when the group with higher working values is in a poor external environment, they can maintain the stable salary level. With the recovery in business activity, the group with higher self values can present better bounce strength. In terms of methods of enterprise’s employee incentive, it can be observed from the long-term salary level that it is more effective to motivate employees with intrinsic motivation and it can provide reference for enterprise’s human resource managers to make incentive strategy.
Yeh, Ya-Lan, and 葉雅嵐. "Left Atrial Longitudinal Deformation Analysis by Two-Dimensional Speckle Tracking Echocardiography in Dogs with Mitral Valve Disease." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/20959914474773011631.
Full text國立中興大學
獸醫學系暨研究所
100
Left atrial (LA) remodeling, one of the major pathophysiological results of chronic myxomatous mitral valve disease (MMVD), not only serves as a compensatory mechanism for prevention of overt pulmonary edema, but also gauges the disease severity and the risk of developing left-sided congestive heart failure. Many methods regarding quantification LA size and function have been presented, but effective assessment of LA remodeling remains a challenging issue. Recently, the feasibility of quantification of LA longitudinal myocardial deformation dynamics by two-dimensional speckle tracking echocardiography (2D-STE) has been approved in humans. However, there is a paucity of related literature in veterinary medicine. To explore the application of quantification of LA longitudinal myocardial deformation dynamics by 2D-STE in small animals, we analysis and compare the parameters of left atrial longitudinal dynamics deformation in dogs with and without myxomatous mitral valve disease. 21 dogs without any anomaly of cardiac valve were as Controls. Dogs with MMVD were further divided into 3 groups: 13 dogs without obvious related cardiac remodeling (MMVD-1), 9 with obvious cardiac remodeling (MMVD-2), and 7 with clinical signs of heart failure (MMVD-3). The results revealed LA longitudinal strain was higher in MMVD-1 than that in controls, highest in MMVD-2, but declined in MMVD-3. Similar results was found in LA longitudinal strain rate. Significant correlations between these parameters and corresponding LA emptying fractions showed these LA longitudinal deformation parameters may reflect the function of LA modulating ventricular filling. However, there was no significant difference in the parameters among all groups. We thought assessing LA remodeling via LA longitudinal deformation analysis by STE in small animal maybe needs improvement for application.
Hsueh, Hui-Chuan, and 薛惠娟. "Power comparison about repeated measures, hierarchical linear model and regression model in analyzing longitudinal data with missing values." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/12944805989680506107.
Full text國立臺北大學
統計學系
98
Hierarchical Linear Model (HLM) and Repeated Measures (RM) can be used to analyze the longitudinal data. The data which can be used in RM will be fewer than that in HLM when there are missing values. Hua Fang (2006) compared HLM with RM when the data is complete. In this paper, we discuss the power of HLM vs. RM when there are missing values. Moreover, the traditional regression model is also included in the comparison. This research simulate data by different missing types, MCAR and MCAR_IT, and use HLM, RM with deleting missing values, RM with imputing missing values and regression model to perform the analysis. Probability of Type I error and powers are to be discussed and suggest are proposed in selecting model methods. This research concludes that the imputation is not helpful in RM ana HLM is a better method in analyzing longitudinal data with missing values.