Made available in DSpace on 2015-03-26T13:32:22Z (GMT). No. of bitstreams: 1 texto completo.pdf: 434501 bytes, checksum: 0ab5e3021a0cbd11c8c868f09b269488 (MD5) Previous issue date: 2014-02-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The analysis of growth curves of animals has been widely used to increase the efficiency of beef cattle ranching. Related to growth curves with nonlinear mixed models strategic, studies have strategic applications in genetic improving programs in defining selection criteria for earliness and weight gain, aimed at, that for each individual is estimated a random coefficient, facilitating identification and selection of more efficient animals based on the coefficients. This methodology considers the variability between and within individuals. The objective of this study was to evaluate the efficiency of the adjustment of growth curves by nonlinear mixed models. Nonlinear models, Michaelis-Menten Modified, Logistic, von Bertalanffy, Gompertz, Richards and Brody, were fitted, with and without the incorporation of random effects for analysis of growth in beef cattle Tabapuã race. For comparison between fixed and mixed models were used the following adjustment quality evaluators: Akaike s information criterion (AIC), Bayesian information criterion (BIC), mean absolute deviation (DMA), mean square error (MSE) and coefficient of determination (R2). The use of nonlinear mixed model was efficient to describe bovine growth curves. / A análise de curvas de crescimento de animais tem sido muito utilizada para aumentar a eficiência da pecuária de corte. Estudos relacionados a curvas de crescimento com modelos não lineares mistos podem ter aplicações estratégicas em programas de melhoramento genético na definição de critérios de seleção para precocidade e ganho de peso, tendo em vista, que para cada indivíduo é estimado um coeficiente aleatório, facilitando a identificação e seleção de animais mais eficientes com base nos coeficientes. Essa metodologia considera a variabilidade entre e dentro de indivíduos. O objetivo deste trabalho foi avaliar a eficiência do ajuste de curvas de crescimento através de modelos não lineares mistos. Foram ajustados os modelos não lineares Michaelis-Menten Modificado, Logístico, von Bertalanffy, Gompertz, Richards e Brody, com e sem a incorporação de efeitos aleatórios para análise de curva de crescimento de bovinos de corte da raça Tabapuã. Para comparação entre modelos fixos e mistos foram utilizados os seguintes avaliadores de qualidade de ajuste: critério de informação de Akaike (AIC), critério de informação bayesiano (BIC), desvio médio absoluto (DMA), erro quadrático médio (EQM) e coeficiente de determinação (R2). A utilização de modelos não lineares mistos foi eficiente para descrever curvas de crescimento de bovinos.

During adolescence, individuals place increasing emphasis on peer relations. Both positive and negative relationships contribute to adolescents’ academic performances and well-being. Adolescence is also a period when individuals actively engage in gossiping. Despite the various benefits brought by gossip such as information exchange, norm regulation and amusement, those who are labelled as “gossipers” tend to suffer from bad reputation and thus becoming less favored in friendship selection. Instead of focusing on evident gossiping behaviors, the current study takes an innovative approach of looking at gossip perception and the friendship and disliking relationship between perceived gossipers who are not necessarily real gossipers but are nominated when others were being asked “Who do you think talks you out with other classmates behind your back?” and the self-perceived targets. The research is conducted by applying Meta Analysis and Bayesian Multilevel Random Coefficients Analysis to 11 Hungarian classrooms of the RECENS project “Competition and Negative Networks” (2017) using Stochastic Actor Oriented Modelling (SAOM) in R. Results from Meta Analysis are in line with the expectation that gossip perception should make the self-perceived target less likely to befriend the perceived gossiper and more likely to dislike him/her. No evidence is found to support that having a shared perceived gossiper should bring two self-perceived targets closer or a self-perceived target should be more likely to dislike the friend of the perceived gossiper following Heider’s Balance Theory (1946). However, no gossip perception related effects are found statistically significant according to the results of the Bayesian approach. Overall, gossip perception is not powerful enough to affect adolescents’ attitude, whether positive or negative, towards one another.

Submitted by Rafael de Braga Castilho (rcastilho@fgvmail.br) on 2014-01-06T19:10:15Z No. of bitstreams: 1 MestRafaelCastilho.pdf: 636676 bytes, checksum: f815c7fac86fe9684f4f79cd86ec9f26 (MD5) / Approved for entry into archive by Janete de Oliveira Feitosa (janete.feitosa@fgv.br) on 2014-01-15T17:51:37Z (GMT) No. of bitstreams: 1 MestRafaelCastilho.pdf: 636676 bytes, checksum: f815c7fac86fe9684f4f79cd86ec9f26 (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2014-01-24T12:33:06Z (GMT) No. of bitstreams: 1 MestRafaelCastilho.pdf: 636676 bytes, checksum: f815c7fac86fe9684f4f79cd86ec9f26 (MD5) / Made available in DSpace on 2014-01-24T12:33:23Z (GMT). No. of bitstreams: 1 MestRafaelCastilho.pdf: 636676 bytes, checksum: f815c7fac86fe9684f4f79cd86ec9f26 (MD5) Previous issue date: 2013-10-29 / Estimation of demand and supply in differentiated products markets is a central issue in Empirical Industrial Organization and has been used to study the effects of taxes, merges, introduction of new goods, market power, among others. Logit and Random Coefficients Logit are examples of demand models used to study these effects. For the supply side it is generally supposed a Nash equilibrium in prices. This work presents a detailed discussion of these models of demand and supply as well as the procedure for estimation. Lastly, is made an application to the Brazilian fixed income fund market. / Estimação de demanda e oferta em mercados com produtos diferenciados é uma questão central em organização industrial empírica e tem sido usada para estudar os efeitos de taxas, fusões, introdução de novos bens, poder de mercado, dentre outros. Logit e Logit com coeficientes aleatórios são exemplos de modelos de demanda utilizados para estudar estes efeitos. Para a oferta geralmente é suposto equilíbrio de Nash em preços. Este trabalho apresenta uma discussão detalhada destes modelos de demanda e oferta, assim como o procedimento para estimação. Por fim é feita uma aplicação para o mercado brasileiro de fundos de renda fixa.

The research in the field of travel demand modeling is driven by the need to understand individuals’ behavior in the context of travel-related decisions as accurately as possible. In this regard, the activity-based approach to modeling travel demand has received substantial attention in the past decade, both in the research arena as well as in practice. At the same time, recent efforts have been focused on more fully realizing the potential of activity-based models by explicitly recognizing the multi-dimensional nature of activity-travel decisions. However, as more behavioral elements/dimensions are added, the dimensionality of the model systems tends to explode, making the estimation of such models all but infeasible using traditional inference methods. As a result, analysts and practitioners often trade-off between recognizing attributes that will make a model behaviorally more representative (from a theoretical viewpoint) and being able to estimate/implement a model (from a practical viewpoint). An alternative approach to deal with the estimation complications arising from multi-dimensional choice situations is the technique of composite marginal likelihood (CML). This is an estimation technique that is gaining substantial attention in the statistics field, though there has been relatively little coverage of this method in transportation and other fields. The CML approach is a conceptually and pedagogically simpler simulation-free procedure (relative to traditional approaches that employ simulation techniques), and has the advantage of reproducibility of the results. Under the usual regularity assumptions, the CML estimator is consistent, unbiased, and asymptotically normally distributed. The discussion above indicates that the CML approach has the potential to contribute in the area of travel demand modeling in a significant way. For example, the approach can be used to develop conceptually and behaviorally more appealing models to examine individuals’ travel decisions in a joint framework. The overarching goal of the current research work is to demonstrate the applicability of the CML approach in the area of activity-travel demand modeling and to highlight the enhanced features of the choice models estimated using the CML approach. The goal of the dissertation is achieved in three steps as follows: (1) by evaluating the performance of the CML approach in multivariate situations, (2) by developing multidimensional choice models using the CML approach, and (3) by demonstrating applications of the multidimensional choice models developed in the current dissertation. / text