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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.
61

From here to infinity: sparse finite versus Dirichlet process mixtures in model-based clustering

Frühwirth-Schnatter, Sylvia, Malsiner-Walli, Gertraud January 2019 (has links) (PDF)
In model-based clustering mixture models are used to group data points into clusters. A useful concept introduced for Gaussian mixtures by Malsiner Walli et al. (Stat Comput 26:303-324, 2016) are sparse finite mixtures, where the prior distribution on the weight distribution of a mixture with K components is chosen in such a way that a priori the number of clusters in the data is random and is allowed to be smaller than K with high probability. The number of clusters is then inferred a posteriori from the data. The present paper makes the following contributions in the context of sparse finite mixture modelling. First, it is illustrated that the concept of sparse finite mixture is very generic and easily extended to cluster various types of non-Gaussian data, in particular discrete data and continuous multivariate data arising from non-Gaussian clusters. Second, sparse finite mixtures are compared to Dirichlet process mixtures with respect to their ability to identify the number of clusters. For both model classes, a random hyper prior is considered for the parameters determining the weight distribution. By suitable matching of these priors, it is shown that the choice of this hyper prior is far more influential on the cluster solution than whether a sparse finite mixture or a Dirichlet process mixture is taken into consideration.
62

Desenvolvimento e validação de modelo preditivo e avaliação de testes de diagnóstico por classe latente para o parasitismo por L. chagasi em cães atendidos no Hospital Veterinário Universitário da UFPI, Teresina / Development and validation of a predective model and assessment of accuracy of diagnostic tests by means of latent class for parasitism by Leishmania chagasi in dogs admitted at the Veterinary Hospital of the Federal University of Piauí, Teresina, Brazil

Marcus Vinicius Gouvêa 30 April 2011 (has links)
A leishmaniose visceral americana (LVA) é uma doença em expansão no Brasil, para a qual se dispõem de poucas, e aparentemente ineficientes, estratégias de controle. Um dos grandes problemas para a contenção da leishmaniose visceral americana é a falta de um método acurado de identificação dos cães infectados, considerados os principais reservatórios da doença no meio urbano. Neste sentido, a caracterização de marcadores clínico-laboratoriais da infecção neste reservatório e a avaliação mais adequada do desempenho de testes para diagnóstico da infecção podem contribuir para aumentar a efetividade das estratégias de controle da LVA. Com isso, o presente estudo tem dois objetivos principais: (1) desenvolver e validar um modelo de predição para o parasitismo por Leishmania chagasi em cães, baseado em resultados de testes sorológicos e sinais clínicos e (2) avaliar a sensibilidade e especificidade de critérios clínicos, sorológicos e parasitológicos para detecção de infecção canina por L. chagasi mediante análise de classe latente. O primeiro objetivo foi desenvolvido a partir de estudo em que foram obtidos dados de exames clínico, sorológico e parasitológico de todos os cães, suspeitos ou não de LVA, atendidos no Hospital Veterinário Universitário da Universidade Federal do Piauí (HVU-UFPI), em Teresina, nos anos de 2003 e 2004, totalizando 1412 animais. Modelos de regressão logística foram construídos com os animais atendidos em 2003 com a finalidade de desenvolver um modelo preditivo para o parasitismo com base nos sinais clínicos e resultados de sorologia por Imunofluorescência Indireta (IFI). Este modelo foi validado nos cães atendidos no hospital em 2004. Para a avaliação da área abaixo da curva ROC (auROC), sensibilidade, especificidade, valores preditivos positivo (VPP), valores preditivos negativo (VPN) e acurácia global, foram criados três modelos: um somente baseado nas variáveis clínicas, outro considerando somente o resultado sorológico e um último considerando conjuntamente a clínica e a sorologia. Dentre os três, o último modelo apresentou o melhor desempenho (auROC=90,1%, sensibilidade=82,4%, especificidade=81,6%, VPP=73,4%, VPN=88,2% e acurácia global=81,9%). Conclui-se que o uso de modelos preditivos baseados em critérios clínicos e sorológicos para o diagnóstico da leishmaniose visceral canina pode ser de utilidade no processo de avaliação da infecção canina, promovendo maior agilidade na contenção destes animais com a finalidade de reduzir os níveis de transmissão. O segundo objetivo foi desenvolvido por meio de um estudo transversal com 715 cães de idade entre 1 mês e 13 anos, com raça variada avaliados por clínicos veterinários no HVU-UFPI, no período de janeiro a dezembro de 2003. As sensibilidades e especificidades de critérios clínicos, sorológicos e parasitológicos para detecção de infecção canina por Leishmania chagasi foram estimadas por meio de análise de classe latente, considerando quatro modelos de testes e diferentes pontos de corte. As melhores sensibilidades estimadas para os critérios clínico, sorológico e parasitológico foram de 60%, 95% e 66%, respectivamente. Já as melhores especificidades estimadas para os critérios clínico, sorológico e parasitológico foram de 77%, 90% e 100%, respectivamente. Conclui-se que o uso do exame parasitológico como padrão-ouro para validação de testes diagnósticos não é apropriado e que os indicadores de acurácia dos testes avaliados são insuficientes e não justificam que eles sejam usados isoladamente para diagnóstico da infecção com a finalidade de controle da doença. / American visceral leishmaniasis (AVL) is an expanding disease in Brazil, for which few, and apparently inefficient, control strategies are available. A major problem for the containment of visceral leishmaniasis is the lack of an accurate test for the identification of infected dogs, which are considered the main reservoirs of the disease in urban areas. In this sense, the characterization of clinical and laboratory markers of the infection in this reservoir, as well as, a more appropriate assessment of the performance of tests for the diagnosis of infection, might increase the effectiveness of control strategies for AVL. Thus, this study has two main objectives: (1) to develop and validate a prediction model for parasitism by Leishmania chagasi in dogs, based on the results of serological tests and clinical signs and (2) to evaluate the sensitivity and specificity of a clinical criterion, and of parasitological and serological tests for canine infection by L. chagasi using latent class analysis. The first goal was developed from a study in which clinical, serological and parasitological data were obtained for all dogs, suspicious or not to AVL, admitted at the Veterinary Hospital at the Federal University of Piauí, Teresina, in the years of 2003 and 2004, totaling 1412 animals. Logistic regression models were constructed with the animals admitted in 2003 with the aim of developing a predictive model for parasitism based on clinical signs and results of serology by indirect immunofluorescence (IIF). This model was validated in dogs admitted at the hospital in 2004. To evaluate the area under the ROC curve (AuROC), sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy, three models were developed: one based only on clinical variables, other only with the serological results and a final model based on both the clinical and serological data. Among the three, the last model showed the best performance (AuROC=90.1%, sensitivity 82.4%, specificity=81.6%, PPV=73.4% NPV=88.2% and overall accuracy=81.9%). It is concluded that the use of predictive models based on clinical and serological data for diagnosis of canine visceral leishmaniasis might be useful in the evaluation of canine infection, allowing the anticipation of ontainment of these animals in order to reduce transmission levels. The second goal was developed through a cross-sectional study of 715 dogs aged between 1 month and 13 years, with varied races evaluated by veterinarians at VUH-UFPI in the period January to December 2003. The sensitivities and specificities of clinical, parasitological and serological tests for detection of canine infection by Leishmania chagasi were estimated using latent class analysis, considering four types of models and different cutoffs. The best sensitivity estimates for the clinical, serological and parasitological tests were 60%, 95% and 66% respectively. The best estimates for the specificity of clinical, serological and parasitological tests were 77%, 90% and 100% respectively. It is concluded that the use of parasitological assays as the gold standard for validation of diagnostic tests is not appropriate and that the indicators of accuracy of the tests evaluated are insufficient to justify that they are used alone for diagnosis of infection in order to control the disease.
63

How Corporate Concentration Gives Rise to the Movement of Movements: Monsanto and La Via Campesina (1990–2011)

Giacomini, Terran 15 September 2011 (has links)
As of 2011 a revolutionary ‘movement of movements’ is emerging coterminous with environmental crises and various other crises including corporate globalization. This study sheds theoretical and empirical light on the origins of the movement of movements. Employing gendered, ethnicized class analysis, this study investigates Karl Marx’s (1867) central discovery in Capital volume one, chapter 32 that corporate concentration and organization impels workers to resist and become a revolutionary class for themselves. Data is derived from investigation into the social movement La Via Campesina’s (‘the peasant way’) struggle against Monsanto Corporation in India, the European Union and Brazil during two periods of Monsanto’s concentration (1996–1998 and 2007–2011). Findings indicate that, in the process of Monsanto’s concentration, there was a leap forward in the formation and actions of the movement of movements. This study concludes that corporate concentration and global organization significantly impels the formation of the movement of movements. / Social Science and Humanities Research Council (SSHRC)
64

Caracterização da síndrome metabólica utilizando a análise de classes latentes

Ladwig, Ruben January 2015 (has links)
Objetivo: Identificar principais componentes da síndrome metabólica e características associadas, bem como identificar os perfis de anormalidades e sua variabilidade étnica. Métodos: Estudo transversal envolvendo 14544 participantes da linha de base do Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil). Com idade entre 35 e 74 anos de diferentes regiões do Brasil. Foi feita uma análise fatorial exploratória em variáveis associadas à síndrome metabólica, com uma análise de agrupamento dos participantes em função de seus escores fatoriais. Paralelamente, análise de classes latentes foi feita em toda a amostra, após categorização das variáveis. As proporções das classes foram avaliadas em cada estrato de raça/cor dos participantes. Resultados: Na amostra ELSA observou-se três fatores que explicam 97,7% da variabilidade das variáveis associadas à síndrome: componentes da síndrome metabólica e inflamação; hipertensão; enzimas hepáticas. Na análise de classes latentes observaram-se seis perfis de manifestação dos componentes síndrome, sendo que o perfil com maior prevalência no estudo é de pessoas com sobrepeso e hiperglicemia, mas com probabilidade menor de apresentar hipertensão. Nesta classe, a prevalência da síndrome metabólica (definida pelo critério conjunto) é de 42%. Esta classe é mais comum entre os indígenas do que nas demais categorias de raça/cor. Conclusão: A síndrome metabólica se manifesta de formas distintas na população. A investigação da associação destas manifestações com desfechos de interesse poderia aprofundar o conhecimento sobre a síndrome metabólica. / Objective: identify key components of the metabolic syndrome and associated features, as well as identify abnormalities groups and its ethnic variability. Methods: Cross-sectional study involving 14544 baseline participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), aged between 35 and 74 years, from different country regions. A exploratory factorial analysis was done on selected variables associated with the metabolic syndrome, with a cluster analysis done on the participants factor scores. At the same time, a latent class analysis was done on all participants and on the subset that had metabolic syndrome diagnosis, after the variables were categorized. The proportions of classes were evaluated in each stratum of race/color of the participants. Results: We observed 3 factors on the ELSA sample. They explain 97.7% of the variability of the variables associates with the metabolic syndrome: the metabolic syndrome and inflammation components; hypertension, markers of the non-alcoholic fatty liver disease. In the latent class analysis, we observed 6 classes of metabolic syndrome expression. The proportions of classes were evaluated in each stratum of race/color of the participants. The most prevalent class was of overweight and hiperglicemic subjects, with lower probability of having hipertension. In this class, the metabolic syndrome prevalence is of 42%. This class is more common in indians than in other groups of race/color. Conclusion: The metabolic syndrome is manifested in different ways in the population. The research of the association of these different manifestations with selected outcomes could further the current knowledge on the metabolic syndrome.
65

Desenvolvimento e validação de modelo preditivo e avaliação de testes de diagnóstico por classe latente para o parasitismo por L. chagasi em cães atendidos no Hospital Veterinário Universitário da UFPI, Teresina / Development and validation of a predective model and assessment of accuracy of diagnostic tests by means of latent class for parasitism by Leishmania chagasi in dogs admitted at the Veterinary Hospital of the Federal University of Piauí, Teresina, Brazil

Marcus Vinicius Gouvêa 30 April 2011 (has links)
A leishmaniose visceral americana (LVA) é uma doença em expansão no Brasil, para a qual se dispõem de poucas, e aparentemente ineficientes, estratégias de controle. Um dos grandes problemas para a contenção da leishmaniose visceral americana é a falta de um método acurado de identificação dos cães infectados, considerados os principais reservatórios da doença no meio urbano. Neste sentido, a caracterização de marcadores clínico-laboratoriais da infecção neste reservatório e a avaliação mais adequada do desempenho de testes para diagnóstico da infecção podem contribuir para aumentar a efetividade das estratégias de controle da LVA. Com isso, o presente estudo tem dois objetivos principais: (1) desenvolver e validar um modelo de predição para o parasitismo por Leishmania chagasi em cães, baseado em resultados de testes sorológicos e sinais clínicos e (2) avaliar a sensibilidade e especificidade de critérios clínicos, sorológicos e parasitológicos para detecção de infecção canina por L. chagasi mediante análise de classe latente. O primeiro objetivo foi desenvolvido a partir de estudo em que foram obtidos dados de exames clínico, sorológico e parasitológico de todos os cães, suspeitos ou não de LVA, atendidos no Hospital Veterinário Universitário da Universidade Federal do Piauí (HVU-UFPI), em Teresina, nos anos de 2003 e 2004, totalizando 1412 animais. Modelos de regressão logística foram construídos com os animais atendidos em 2003 com a finalidade de desenvolver um modelo preditivo para o parasitismo com base nos sinais clínicos e resultados de sorologia por Imunofluorescência Indireta (IFI). Este modelo foi validado nos cães atendidos no hospital em 2004. Para a avaliação da área abaixo da curva ROC (auROC), sensibilidade, especificidade, valores preditivos positivo (VPP), valores preditivos negativo (VPN) e acurácia global, foram criados três modelos: um somente baseado nas variáveis clínicas, outro considerando somente o resultado sorológico e um último considerando conjuntamente a clínica e a sorologia. Dentre os três, o último modelo apresentou o melhor desempenho (auROC=90,1%, sensibilidade=82,4%, especificidade=81,6%, VPP=73,4%, VPN=88,2% e acurácia global=81,9%). Conclui-se que o uso de modelos preditivos baseados em critérios clínicos e sorológicos para o diagnóstico da leishmaniose visceral canina pode ser de utilidade no processo de avaliação da infecção canina, promovendo maior agilidade na contenção destes animais com a finalidade de reduzir os níveis de transmissão. O segundo objetivo foi desenvolvido por meio de um estudo transversal com 715 cães de idade entre 1 mês e 13 anos, com raça variada avaliados por clínicos veterinários no HVU-UFPI, no período de janeiro a dezembro de 2003. As sensibilidades e especificidades de critérios clínicos, sorológicos e parasitológicos para detecção de infecção canina por Leishmania chagasi foram estimadas por meio de análise de classe latente, considerando quatro modelos de testes e diferentes pontos de corte. As melhores sensibilidades estimadas para os critérios clínico, sorológico e parasitológico foram de 60%, 95% e 66%, respectivamente. Já as melhores especificidades estimadas para os critérios clínico, sorológico e parasitológico foram de 77%, 90% e 100%, respectivamente. Conclui-se que o uso do exame parasitológico como padrão-ouro para validação de testes diagnósticos não é apropriado e que os indicadores de acurácia dos testes avaliados são insuficientes e não justificam que eles sejam usados isoladamente para diagnóstico da infecção com a finalidade de controle da doença. / American visceral leishmaniasis (AVL) is an expanding disease in Brazil, for which few, and apparently inefficient, control strategies are available. A major problem for the containment of visceral leishmaniasis is the lack of an accurate test for the identification of infected dogs, which are considered the main reservoirs of the disease in urban areas. In this sense, the characterization of clinical and laboratory markers of the infection in this reservoir, as well as, a more appropriate assessment of the performance of tests for the diagnosis of infection, might increase the effectiveness of control strategies for AVL. Thus, this study has two main objectives: (1) to develop and validate a prediction model for parasitism by Leishmania chagasi in dogs, based on the results of serological tests and clinical signs and (2) to evaluate the sensitivity and specificity of a clinical criterion, and of parasitological and serological tests for canine infection by L. chagasi using latent class analysis. The first goal was developed from a study in which clinical, serological and parasitological data were obtained for all dogs, suspicious or not to AVL, admitted at the Veterinary Hospital at the Federal University of Piauí, Teresina, in the years of 2003 and 2004, totaling 1412 animals. Logistic regression models were constructed with the animals admitted in 2003 with the aim of developing a predictive model for parasitism based on clinical signs and results of serology by indirect immunofluorescence (IIF). This model was validated in dogs admitted at the hospital in 2004. To evaluate the area under the ROC curve (AuROC), sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and overall accuracy, three models were developed: one based only on clinical variables, other only with the serological results and a final model based on both the clinical and serological data. Among the three, the last model showed the best performance (AuROC=90.1%, sensitivity 82.4%, specificity=81.6%, PPV=73.4% NPV=88.2% and overall accuracy=81.9%). It is concluded that the use of predictive models based on clinical and serological data for diagnosis of canine visceral leishmaniasis might be useful in the evaluation of canine infection, allowing the anticipation of ontainment of these animals in order to reduce transmission levels. The second goal was developed through a cross-sectional study of 715 dogs aged between 1 month and 13 years, with varied races evaluated by veterinarians at VUH-UFPI in the period January to December 2003. The sensitivities and specificities of clinical, parasitological and serological tests for detection of canine infection by Leishmania chagasi were estimated using latent class analysis, considering four types of models and different cutoffs. The best sensitivity estimates for the clinical, serological and parasitological tests were 60%, 95% and 66% respectively. The best estimates for the specificity of clinical, serological and parasitological tests were 77%, 90% and 100% respectively. It is concluded that the use of parasitological assays as the gold standard for validation of diagnostic tests is not appropriate and that the indicators of accuracy of the tests evaluated are insufficient to justify that they are used alone for diagnosis of infection in order to control the disease.
66

Caracterização da síndrome metabólica utilizando a análise de classes latentes

Ladwig, Ruben January 2015 (has links)
Objetivo: Identificar principais componentes da síndrome metabólica e características associadas, bem como identificar os perfis de anormalidades e sua variabilidade étnica. Métodos: Estudo transversal envolvendo 14544 participantes da linha de base do Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil). Com idade entre 35 e 74 anos de diferentes regiões do Brasil. Foi feita uma análise fatorial exploratória em variáveis associadas à síndrome metabólica, com uma análise de agrupamento dos participantes em função de seus escores fatoriais. Paralelamente, análise de classes latentes foi feita em toda a amostra, após categorização das variáveis. As proporções das classes foram avaliadas em cada estrato de raça/cor dos participantes. Resultados: Na amostra ELSA observou-se três fatores que explicam 97,7% da variabilidade das variáveis associadas à síndrome: componentes da síndrome metabólica e inflamação; hipertensão; enzimas hepáticas. Na análise de classes latentes observaram-se seis perfis de manifestação dos componentes síndrome, sendo que o perfil com maior prevalência no estudo é de pessoas com sobrepeso e hiperglicemia, mas com probabilidade menor de apresentar hipertensão. Nesta classe, a prevalência da síndrome metabólica (definida pelo critério conjunto) é de 42%. Esta classe é mais comum entre os indígenas do que nas demais categorias de raça/cor. Conclusão: A síndrome metabólica se manifesta de formas distintas na população. A investigação da associação destas manifestações com desfechos de interesse poderia aprofundar o conhecimento sobre a síndrome metabólica. / Objective: identify key components of the metabolic syndrome and associated features, as well as identify abnormalities groups and its ethnic variability. Methods: Cross-sectional study involving 14544 baseline participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), aged between 35 and 74 years, from different country regions. A exploratory factorial analysis was done on selected variables associated with the metabolic syndrome, with a cluster analysis done on the participants factor scores. At the same time, a latent class analysis was done on all participants and on the subset that had metabolic syndrome diagnosis, after the variables were categorized. The proportions of classes were evaluated in each stratum of race/color of the participants. Results: We observed 3 factors on the ELSA sample. They explain 97.7% of the variability of the variables associates with the metabolic syndrome: the metabolic syndrome and inflammation components; hypertension, markers of the non-alcoholic fatty liver disease. In the latent class analysis, we observed 6 classes of metabolic syndrome expression. The proportions of classes were evaluated in each stratum of race/color of the participants. The most prevalent class was of overweight and hiperglicemic subjects, with lower probability of having hipertension. In this class, the metabolic syndrome prevalence is of 42%. This class is more common in indians than in other groups of race/color. Conclusion: The metabolic syndrome is manifested in different ways in the population. The research of the association of these different manifestations with selected outcomes could further the current knowledge on the metabolic syndrome.
67

Caracterização da síndrome metabólica utilizando a análise de classes latentes

Ladwig, Ruben January 2015 (has links)
Objetivo: Identificar principais componentes da síndrome metabólica e características associadas, bem como identificar os perfis de anormalidades e sua variabilidade étnica. Métodos: Estudo transversal envolvendo 14544 participantes da linha de base do Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil). Com idade entre 35 e 74 anos de diferentes regiões do Brasil. Foi feita uma análise fatorial exploratória em variáveis associadas à síndrome metabólica, com uma análise de agrupamento dos participantes em função de seus escores fatoriais. Paralelamente, análise de classes latentes foi feita em toda a amostra, após categorização das variáveis. As proporções das classes foram avaliadas em cada estrato de raça/cor dos participantes. Resultados: Na amostra ELSA observou-se três fatores que explicam 97,7% da variabilidade das variáveis associadas à síndrome: componentes da síndrome metabólica e inflamação; hipertensão; enzimas hepáticas. Na análise de classes latentes observaram-se seis perfis de manifestação dos componentes síndrome, sendo que o perfil com maior prevalência no estudo é de pessoas com sobrepeso e hiperglicemia, mas com probabilidade menor de apresentar hipertensão. Nesta classe, a prevalência da síndrome metabólica (definida pelo critério conjunto) é de 42%. Esta classe é mais comum entre os indígenas do que nas demais categorias de raça/cor. Conclusão: A síndrome metabólica se manifesta de formas distintas na população. A investigação da associação destas manifestações com desfechos de interesse poderia aprofundar o conhecimento sobre a síndrome metabólica. / Objective: identify key components of the metabolic syndrome and associated features, as well as identify abnormalities groups and its ethnic variability. Methods: Cross-sectional study involving 14544 baseline participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), aged between 35 and 74 years, from different country regions. A exploratory factorial analysis was done on selected variables associated with the metabolic syndrome, with a cluster analysis done on the participants factor scores. At the same time, a latent class analysis was done on all participants and on the subset that had metabolic syndrome diagnosis, after the variables were categorized. The proportions of classes were evaluated in each stratum of race/color of the participants. Results: We observed 3 factors on the ELSA sample. They explain 97.7% of the variability of the variables associates with the metabolic syndrome: the metabolic syndrome and inflammation components; hypertension, markers of the non-alcoholic fatty liver disease. In the latent class analysis, we observed 6 classes of metabolic syndrome expression. The proportions of classes were evaluated in each stratum of race/color of the participants. The most prevalent class was of overweight and hiperglicemic subjects, with lower probability of having hipertension. In this class, the metabolic syndrome prevalence is of 42%. This class is more common in indians than in other groups of race/color. Conclusion: The metabolic syndrome is manifested in different ways in the population. The research of the association of these different manifestations with selected outcomes could further the current knowledge on the metabolic syndrome.
68

Fatores associados ao aleitamento materno exclusivo no primeiro m?s de idade

Cerqueira, Pryscila de Argolo 31 March 2015 (has links)
Submitted by Ricardo Cedraz Duque Moliterno (ricardo.moliterno@uefs.br) on 2016-07-15T00:33:15Z No. of bitstreams: 1 Disserta??o.pdf: 1171570 bytes, checksum: b9d60d56611f65106bfe64f3ae580d37 (MD5) / Made available in DSpace on 2016-07-15T00:33:15Z (GMT). No. of bitstreams: 1 Disserta??o.pdf: 1171570 bytes, checksum: b9d60d56611f65106bfe64f3ae580d37 (MD5) Previous issue date: 2015-03-31 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Exclusive breastfeeding (EBF) during the first six months of life is essential to promote proper growth and development, and contribute to reducing child mortality. Socioeconomic, demographic, biological, behavioral, psychological among others, interfere with this practice. However, the measurement of some variables has been a challenge due to the subjectivity and limitations of self-report data, both prone to errors. The identification of similar characteristics patterns among nursing mothers and health professionals allows better understanding of the between interrelationship the various factors associated with breastfeeding, and the role of each individual in that process. To this end, theoretical models can be used by Latent Class Analysis (LCA); statistical technique that seeks to identify characteristics of individuals with similar patterns of behavior; and categorize them into their most likely class their responses. The objectives of this study were: a) identify behavior patterns towards EBF among nursing mothers and health professionals; b) evaluates the factors associated with EBF cessation within the first month of life, including variables that were not previously examined in the literature. This is a cohort study with cross-sectional analysis, which used LCA to design a model with four constructs (maternal emotional state, availability to breastfeeding, maternal attitude towards breastfeeding; and health professional?s attitude towards breastfeeding), each with two latent classes, from 15 indicators surveyed in a birth cohort composed 1.309 women interviewed in the first month after delivery. In addition, logistic regression analysis was also performed to investigate the association between EBF interruption at 1 month of life and the latent variables and other covariates. Four constructs were defined using LCA, three related to maternal characteristics: attitude, emotional state and availability to breastfeeding, and on attitude of health professionals on breastfeeding. The frequency of women with unfavorable emotional state was 36.5%; 14.7% had less availability to breastfeed; and 41.5% had a negative attitude towards breastfeeding; and 62.0% of health professionals had negative attitude towards breastfeeding. The classes unfavorable maternal emotional state (OR=1.62; IC95%: 1.28-2.05), unfavorable health professional?s attitude towards breastfeeding (OR=1.31; IC95%: 1.03-1.67) and negative maternal attitude to breastfeeding (OR=2.18; IC95%: 1.73-2.75) were associated with EBF interruption in the 1st month of life. Maternal education up to elementary school (OR=1.47; IC95%: 1.15-1.89) and family income less than one minimum wage (OR=1.41; IC95%: 1.10-1.81) also presented statistical significance for the denouement. The results for education and income were consistent with the literature. The LCA demonstrated behavior patterns of nursing mothers and health professionals on the EBF. The study found new factors associated with interruption of EBF at 1 month of life. / O aleitamento materno exclusivo (AME) nos primeiros seis meses de vida ? fundamental para promover bom crescimento e desenvolvimento, al?m de contribuir para a redu??o da morbimortalidade infantil. Fatores socioecon?micos, demogr?ficos, biol?gicos, comportamentais, psicol?gicos entre outros, interferem nesta pr?tica. Entretanto, a mensura??o de algumas vari?veis tem se mostrado um desafio devido ? subjetividade e as limita??es de dados autorrelatados, ambos propensos a erros. A identifica??o de padr?es de caracter?sticas similares entre nutrizes e profissionais de sa?de permite compreender melhor a interrela??o entre os diversos fatores associados ? pr?tica da amamenta??o, e o papel de cada indiv?duo nesse processo. Para tal, podem ser utilizados modelos te?ricos, mediante An?lise de Classes Latentes (ACL); uma t?cnica estat?stica que busca identificar caracter?sticas de indiv?duos com padr?es similares de comportamentos; e categoriz?-los em sua classe mais prov?vel, dadas as suas respostas. Os objetivos deste trabalho foram: a) identificar padr?es de comportamento relacionados ao AME entre nutrizes e profissionais de sa?de; e b) avaliar os fatores associados ? interrup??o do AME no primeiro m?s de vida, incluindo vari?veis latentes. Trata-se de um estudo de coorte com an?lise transversal, que utilizou ACL para elaborar um modelo com quatro constructos (estado emocional materno, disponibilidade para amamentar, atitudes maternas e dos profissionais de sa?de quanto ? amamenta??o), cada um com duas classes latentes a partir de 15 indicadores pesquisados em uma coorte de nascidos vivos composta por 1.309 mulheres entrevistadas no primeiro m?s p?s-parto. Ademais, foi realizada an?lise de regress?o log?stica para investigar a associa??o entre a interrup??o do AME no primeiro m?s de vida e as vari?veis latentes definidas e outras covari?veis. Foram definidos quatro constructos, utilizando ACL, tr?s relacionados ?s caracter?sticas maternas: atitude, estado emocional e disponibilidade para amamentar, e um sobre atitude dos profissionais de sa?de quanto ? amamenta??o. A frequ?ncia de mulheres com estado emocional desfavor?vel foi de 36,5%; 14,7% apresentaram menor disponibilidade para amamentar e 41,5% informaram atitudes negativas quanto ? amamenta??o; e 62,0% dos profissionais de sa?de apresentaram atitude desfavor?vel quanto ? amamenta??o. As classes estado emocional materno desfavor?vel (OR=1,62; IC95%: 1,28-2,05), atitude do profissional de sa?de desfavor?vel quanto ? amamenta??o (OR=1,31; IC95%: 1,03-1,67) e atitude materna negativa quanto ? amamenta??o (OR=2,18; IC95%: 1,73-2,75) associaram-se com a interrup??o do AME no primeiro m?s de vida. Escolaridade materna at? ensino fundamental (OR=1,47; IC95%: 1,15-1,89) e renda familiar inferior a um sal?rio m?nimo (OR=1,41; IC95%: 1,10-1,81), tamb?m foram significativamente associados ao desfecho. Os resultados encontrados para escolaridade e renda apresentaram-se concordantes com a literatura. A ACL demonstrou padr?es de comportamentos de nutrizes e profissionais de sa?de quanto ao AME. O estudo encontrou novos fatores associados ? interrup??o do AME no primeiro m?s de vida.
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Pathological and non-pathological variants of restrictive eating behaviors in middle childhood: A latent class analysis

Schmidt, Ricarda, Vogel, Mandy, Hiemisch, Andreas, Kiess, Wieland, Hilbert, Anja 29 May 2019 (has links)
Although restrictive eating behaviors are very common during early childhood, their precise nature and clinical correlates remain unclear. Especially, there is little evidence on restrictive eating behaviors in older children and their associations with children's shape concern. The present population-based study sought to delineate subgroups of restrictive eating patterns in N = 799 7-14 year old children. Using Latent Class Analysis, children were classified based on six restrictive eating behaviors (for example, picky eating, food neophobia, and eating-related anxiety) and shape concern, separately in three age groups. For cluster validation, sociodemographic and objective anthropometric data, parental feeding practices, and general and eating disorder psychopathology were used. The results showed a 3-cluster solution across all age groups: an asymptomatic class (Cluster 1), a class with restrictive eating behaviors without shape concern (Cluster 2), and a class showing restrictive eating behaviors with prominent shape concern (Cluster 3). The clusters differed in all variables used for validation. Particularly, the proportion of children with symptoms of avoidant/restrictive food intake disorder was greater in Cluster 2 than Clusters 1 and 3. The study underlined the importance of considering shape concern to distinguish between different phenotypes of children's restrictive eating patterns. Longitudinal data are needed to evaluate the clusters' predictive effects on children's growth and development of clinical eating disorders.
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Applying Latent Class Analysis on Cancer Registry Data to Identify and Compare Health Disparity Profiles in Colorectal Cancer Surgical Treatment Delay

Ishino, Francisco A. M., Odame, Emmanuel A., Villalobos, Kevin, Whiteside, Martin, Mamudu, Hadii, Williams, Faustine 01 January 2021 (has links)
Context: Colorectal cancer (CRC) surgical treatment delay (TD) has been associated with mortality and morbidity; however, disparities by TD profiles are unknown. Objectives: This study aimed to identify CRC patient profiles of surgical TD while accounting for differences in sociodemographic, health insurance, and geographic characteristics. Design: We used latent class analysis (LCA) on 2005-2015 Tennessee Cancer Registry data of CRC patients and observed indicators that included sex/gender, age at diagnosis, marital status (single/married/divorced/widowed), race (White/Black/other), health insurance type, and geographic residence (non-Appalachian/Appalachian). Setting: The state of Tennessee in the United States that included both Appalachian and non-Appalachian counties. Participants: Adult (18 years or older) CRC patients (N = 35 412) who were diagnosed and surgically treated for in situ (n = 1286) and malignant CRC (n = 34 126). Main Outcome Measure: The distal outcome of TD was categorized as 30 days or less and more than 30 days from diagnosis to surgical treatment. Results: Our LCA identified a 4-class solution and a 3-class solution for in situ and malignant profiles, respectively. The highest in situ CRC patient risk profile was female, White, aged 75 to 84 years, widowed, and used public health insurance when compared with respective profiles. The highest malignant CRC patient risk profile was male, Black, both single/never married and divorced/separated, resided in non-Appalachian county, and used public health insurance when compared with respective profiles. The highest risk profiles of in situ and malignant patients had a TD likelihood of 19.3% and 29.4%, respectively. Conclusions: While our findings are not meant for diagnostic purposes, we found that Blacks had lower TD with in situ CRC. The opposite was found in the malignant profiles where Blacks had the highest TD. Although TD is not a definitive marker of survival, we observed that non-Appalachian underserved/underrepresented groups were overrepresented in the highest TD profiles. The observed disparities could be indicative of intervenable risk.

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