Resumo: Dentro da comercialização de frutas, a citricultura é a mais importante. Representa para muitos países, dentre eles, os EUA e o Brasil, uma importante atividade econômica. Porém, esta atividade, vem sofrendo com inúmeras doenças e/ou pragas como a doença do Cancro Cítrico Asiático causada pela bactéria Xanthomonas citri subsp. citri (X. citri). Deste modo, com o objetivo do estudo do genoma funcional da X. citri, um banco de mutantes deste microorganismo foi obtido por meio de inserção aleatória do transposon Tn5, nas quais foram selecionados 53 mutantes que apresentaram, de forma superficial, alterações fenotípica em relação à X. citri selvagem. Para uma avaliação mais precisa, eles passaram por uma nova confirmação de suas alterações fenotípicas, onde foram inoculados em folhas de Citrus sinensis (Laranjeira pêra-Rio) e Citrus limonia (limoeiro cravo) e monitorados durante 16 dias, e aqueles que apresentaram as maiores alterações em relação à selvagem, tiveram confeccionadas para si curvas de crescimento in vivo. Conseguiu-se, desta forma, avaliar quantitativamente o processo patogênico, relacionar seus sintomas com dados numéricos e ainda descobrir detalhes até então não conhecidos. O mapeamento, dos respectivos loci mutados, foi realizado por seqüenciamento de DNA a partir do transposon, demonstrando que a metodologia empregada para a obtenção dos mutantes foi eficiente, conseguiu também revelar diversas proteína ainda hipotéticas, e outras, até então, não considerados como implicados no processo patogênico, como, uma Integrase, Fe-S oxidoredutase, Helicase IV, Receptor Dependente de Ton-B, entre outros / Abstract: Concerning the commercialization of fruits, the citrus production is the most important. It represents for many countries, amongst them, U.S.A. and Brazil, an important economic activity. However, this activity has been suffering with many illnesses and/or plagues as the illness from the Asiatic citrus canker caused by the Xanthomonas citri subsp. citri bacterium (X. citri). In this way, from a bank of mutants of X. citri, gotten by means of random insertion of commercial one derived from transposon Tn5, had been selected 53 mutants that had presented, of superficial form, some type of phenotype alteration in relation to the wild X. citri. To a more necessary evaluation, each one of them passed for a new confirmation of its phenotype alterations, where they had been inoculated in leafs of Citrus sinensis ('Pera' sweet orange) and Citrus limonia ('Rangpur' lime) and monitored during 16 days, and those that had presented the biggest alterations in relation to the savage, had confectioned for itself in planta growth curves. We obtain, in such a way, to evaluate quantitatively the pathogenic process, to relate its symptoms with numerical data and still to discover not known details until then. The mapping of respective locus mutated was carried through by sequencing of DNA from transposon, demonstrating that the methodology used for the attainment of the mutants was efficient and still to disclose diverse genes still hypothetical, and others, until then, not considered as implied in the pathogenic process, as, Integrase, Fe-S oxidoredutase, Helicase IV, TonB-dependent receptor, among others / Orientador: Maria Inês Tiraboschi Ferro / Coorientador: Julio Cezar Franco de Oliveira / Banca: Manoel Victor Franco Lemos / Banca: Mariana Carina Frigieri / Mestre

Introdução: Não há curvas de crescimento satisfatórias para lactentes pré-termo de muito baixo peso (PTMBP) até dois anos de idade corrigida (IC), considerando todos os avanços na assistência neonatal ocorridos nas últimas duas décadas. Objetivo: Elaborar curvas de peso, comprimento e perímetro cefálico até dois anos de IC para uma coorte de lactentes PTMBP; comparar as curvas dos adequados (AIG) e dos pequenos para a idade gestacional (PIG). Método: Uma coorte de lactentes PTMBP admitidos na Unidade de Tratamento Intensivo Neonatal do nosso serviço até 24 horas após nascimento entre novembro/2003 até setembro/2005 foi estudada até dois anos de IC. Lactentes com malformações maiores, síndromes cromossômicas, infecções congênitas e aqueles com menos de três revisões nos primeiros dois anos ambulatório de seguimento foram excluídos. Peso, comprimento e perímetro cefálico foram aferidos rotineiramente até 2 anos de IC. O estudo foi aprovado pelo Comitê de Ética e Pesquisa da Instituição. Resultados: Peso, comprimento e perímetro cefálico foram obtidos de 117 recémnascidos PTMBP (51 AIG e 66 PIG) e foram elaboradas curvas de crescimento para lactentes AIG e PIG. As curvas de peso, comprimento e perímetro cefálico de lactentes AIG e PIG têm o mesmo formato (p=0,211; p=0,193; p=0,463, respectivamente). As médias do peso, comprimento e perímetro cefálico com 40 semanas, 12 meses e 24 meses de IC são significativamente superiores entre lactentes AIG (p<0,01, Mixed Effect Models). Conclusão: As curvas de crescimento obtidas através desse estudo longitudinal são adequadas para monitorização do crescimento pós-natal de pré-termos de muito baixo peso AIG e PIG até 2 anos de IC. / Background: There are no satisfactory growth charts for very low birth weight (VLBW) infants from hospital discharge up to two years corrected age that take in consideration all the changes that occurred in neonatal care in the last twenty years. Objectives: To obtain weight, length and head circumference growth charts up to 2 year corrected age (CA) for a cohort of VLBW infants and, also to compare appropriate (AGA) and small (SGA) for gestational age growth curves. Methods: A cohort of VLBW infants admitted to our NICU up to 24 hours after birth from November 2003 through September 2005, and discharged from hospital was studied up to 2 years CA. Infants with major malformations, chromosomal syndromes, congenital infections (STORCH group), and those that had less than 3 appointments in the follow up clinic in the first two years were excluded. Weight, length, and head circumference were measured monthly up to 2 years CA. Results: Mean weight. Length, and head circumference were obtained from 117 newborns (51 AGA and 66 SGA). Growth curves for AGA and SGA infants were obtained. The weight, length, and head circumference growth curves had the same shape for AGA and SGA infants (p=0.211; p=0.193; p=0.463, respectively). Mean weight, length and head circumference at 40 weeks, 12 months and 24 months CA were significantly higher in AGA than in SGA infants (p<0.01, Mixed effect models). Conclusion: Growth curves obtained in this longitudinal study are adequate for monitoring post-natal growth of AGA and SGA VLBW infants.

Single-head broccoli (Brassica oleracea L. var.italica Plenk) is one of the vegetables with the latest introduction to Brazil and its cultivation has increased gradually over the past decades. This crop has potential to diversify vegetable production in Rio Grande do Sul central area as an economic and horticultural alternative to tobacco growing which widespread among local farmers, as well as to supply regional produce market. The aim of this work was to study growth, development and yield using data generated in two experiments with single-head broccoli hybrids grown in two seasons. The experiments were conducted at the Universidade Federal de Santa Maria(UFSM), Santa Maria, RS, using Legacy and BRO 68 hybrids transplanted on march 22, 2011 and july 30, 2011. We evaluated morphological and productive variables as well as thermal time from transplanting through to the first flower opening. Adjusted growth curves by the cosine model, were determined measuring the length and width of the leaf blade to estimate leaf area, and the variance was analysed in factorial schemes. The model of growth and development of the cosine provided a good fit with the coefficient of determination higher than 70%. Concerning growth, leaf area differed between seasons and between the hybrids in the second season; number of leaves between hybrids in both seasons; component variables of head height, diameter and head green phytomasses, florets and stem apex, between the hybrids in the first season. The thermal time for hybrid Legacy in the first season was 1479.9 degree-days and in the second season was 1285.5 degree-days. The thermal time for hybrid BRO 68 in the first season was 1423.1 degree-days and second season was 1172.8 degree-days. The best model for estimating leaf area was: leaf area = - 0.006981 + 0.000878403 x W1,5, using the width of the leaf for hybrid BRO 68, whereas for 'Legacy ', was: leaf area = 0.0174307 + 0.00000249604 x (L x W)1.5, involving the product of leaf length and width. There was interaction between hybrids and seasons for head green phytomass. Legacy‟ was latest in both seasons and the most productive in the first season, with an average head phytomass of 755.72 g head-1. Both hybrids had the highest average weights in the second season, with 864.43 g head-1 and 862.62 g head-1 for 'BRO 68' and 'Legacy', respectively. / O brócolis de cabeça única (Brassica oleracea L. var.italica Plenk) é uma das hortaliças com a introdução mais recente no Brasil e seu cultivo vem aumentando gradativamente nas últimas décadas. Este cultivo apresenta potencial para a diversificação da produção olerícola, na região central do Rio Grande do Sul como uma alternativa econômica e horticultural para a conversão parcial da fumicultura, à qual se dedicam muitos produtores rurais, bem como, para o abastecimento do mercado regional de hortaliças. O objetivo deste trabalho foi estudar o crescimento, desenvolvimento e produção dos híbridos Legacy e BRO 68 de brócolis de cabeça única cultivados em duas épocas, utilizando dados gerados em experimentos instalados na Universidade Federal de Santa Maria(UFSM), Santa Maria, RS, nas datas de 22/03/2011 e 30/06/2011. Foram avaliadas as variáveis morfológicas e produtivas bem como a soma térmica do transplante até a antese da primeira flor. Ajustou-se as curvas de crescimento pelo modelo do cosseno, determinou-se a medida linear do limbo foliar para estimar a área foliar e fez-se a análise da variância em esquemas fatoriais para as variáveis morfológicas e produtivas. O modelo de crescimento e desenvolvimento do cosseno teve um bom ajuste, com valores do coeficiente de determinação superiores a 70%. Quanto ao crescimento, a área foliar diferiu entre as épocas e entre os dois híbridos na segunda época; o número de folhas entre os híbridos nas duas épocas; as variáveis componentes da cabeça altura, diâmetro e as fitomassas verde da cabeça, dos floretes e do ápice caulinar, entre os dois híbridos na primeira época. A soma térmica para o híbrido Legacy na primeira época foi de 1.479,9 graus-dia e na segunda época foi de 1.285,5 graus-dia. A soma térmica para o híbrido BRO 68 na primeira época foi de 1.423,1 graus-dia e na segunda época foi de 1.172,8 graus-dia. O modelo de melhor ajuste para estimativa da área foliar foi: área foliar = - 0,006981 + 0,000878403 x L1,5, utilizando a medida da largura do limbo foliar, para o híbrido BRO 68, enquanto que, para o Legacy‟, foi: área foliar = 0,0174307 + 0,00000249604 x (C x L)1,5, envolvendo o produto entre o comprimento e a largura. Houve interação entre híbridos e épocas para fitomassa verde da cabeça. O híbrido Legacy foi o mais tardio em ambas as épocas e o mais produtivo na primeira época, com fitomassa média de 755,72 g cabeça-1. Ambos os híbridos obtiveram as maiores fitomassas médias na segunda época, com 864,43 e 862,62 g cabeça-1 para o BRO 68‟ e Legacy‟, respectivamente.

Introdução: Não há curvas de crescimento satisfatórias para lactentes pré-termo de muito baixo peso (PTMBP) até dois anos de idade corrigida (IC), considerando todos os avanços na assistência neonatal ocorridos nas últimas duas décadas. Objetivo: Elaborar curvas de peso, comprimento e perímetro cefálico até dois anos de IC para uma coorte de lactentes PTMBP; comparar as curvas dos adequados (AIG) e dos pequenos para a idade gestacional (PIG). Método: Uma coorte de lactentes PTMBP admitidos na Unidade de Tratamento Intensivo Neonatal do nosso serviço até 24 horas após nascimento entre novembro/2003 até setembro/2005 foi estudada até dois anos de IC. Lactentes com malformações maiores, síndromes cromossômicas, infecções congênitas e aqueles com menos de três revisões nos primeiros dois anos ambulatório de seguimento foram excluídos. Peso, comprimento e perímetro cefálico foram aferidos rotineiramente até 2 anos de IC. O estudo foi aprovado pelo Comitê de Ética e Pesquisa da Instituição. Resultados: Peso, comprimento e perímetro cefálico foram obtidos de 117 recémnascidos PTMBP (51 AIG e 66 PIG) e foram elaboradas curvas de crescimento para lactentes AIG e PIG. As curvas de peso, comprimento e perímetro cefálico de lactentes AIG e PIG têm o mesmo formato (p=0,211; p=0,193; p=0,463, respectivamente). As médias do peso, comprimento e perímetro cefálico com 40 semanas, 12 meses e 24 meses de IC são significativamente superiores entre lactentes AIG (p<0,01, Mixed Effect Models). Conclusão: As curvas de crescimento obtidas através desse estudo longitudinal são adequadas para monitorização do crescimento pós-natal de pré-termos de muito baixo peso AIG e PIG até 2 anos de IC. / Background: There are no satisfactory growth charts for very low birth weight (VLBW) infants from hospital discharge up to two years corrected age that take in consideration all the changes that occurred in neonatal care in the last twenty years. Objectives: To obtain weight, length and head circumference growth charts up to 2 year corrected age (CA) for a cohort of VLBW infants and, also to compare appropriate (AGA) and small (SGA) for gestational age growth curves. Methods: A cohort of VLBW infants admitted to our NICU up to 24 hours after birth from November 2003 through September 2005, and discharged from hospital was studied up to 2 years CA. Infants with major malformations, chromosomal syndromes, congenital infections (STORCH group), and those that had less than 3 appointments in the follow up clinic in the first two years were excluded. Weight, length, and head circumference were measured monthly up to 2 years CA. Results: Mean weight. Length, and head circumference were obtained from 117 newborns (51 AGA and 66 SGA). Growth curves for AGA and SGA infants were obtained. The weight, length, and head circumference growth curves had the same shape for AGA and SGA infants (p=0.211; p=0.193; p=0.463, respectively). Mean weight, length and head circumference at 40 weeks, 12 months and 24 months CA were significantly higher in AGA than in SGA infants (p<0.01, Mixed effect models). Conclusion: Growth curves obtained in this longitudinal study are adequate for monitoring post-natal growth of AGA and SGA VLBW infants.

Submitted by Milena Rubi ( ri.bso@ufscar.br) on 2017-11-07T17:07:00Z No. of bitstreams: 1 SANTOS_Carlos_2017.pdf: 906783 bytes, checksum: bccefa4afd7b8ef5d98df40bff297122 (MD5) / Approved for entry into archive by Milena Rubi ( ri.bso@ufscar.br) on 2017-11-07T17:07:12Z (GMT) No. of bitstreams: 1 SANTOS_Carlos_2017.pdf: 906783 bytes, checksum: bccefa4afd7b8ef5d98df40bff297122 (MD5) / Approved for entry into archive by Milena Rubi ( ri.bso@ufscar.br) on 2017-11-07T17:07:22Z (GMT) No. of bitstreams: 1 SANTOS_Carlos_2017.pdf: 906783 bytes, checksum: bccefa4afd7b8ef5d98df40bff297122 (MD5) / Made available in DSpace on 2017-11-07T17:07:31Z (GMT). No. of bitstreams: 1 SANTOS_Carlos_2017.pdf: 906783 bytes, checksum: bccefa4afd7b8ef5d98df40bff297122 (MD5) Previous issue date: 2017-05-09 / Não recebi financiamento / The productive capacity is conventionally estimated by anamorphic or polymorphic calculated site curves; however, these curves have some limitations. Due to these limitations, the objective of this work was to evaluate the creation of growth curves for site classification by the nonlinear quantile regression method and to compare them with the curves generated by the algebraic difference method. The database was collected in two mesoregions of the state of São Paulo (Paulista and Bauru Metropolitan Macro), with 460 measurements in 98 plots with distinct periods in Eucalyptus sp. The site curves were adjusted according to the Chapman-Richards model using the algebraic difference method for anamorphic and polymorphic curves and nonlinear quantum regression (RNLQ). The results of this work allowed to conclude that the site curves adjusted by the RNLQ method are superior to the curves generated by the algebraic difference method by graphical analysis of the residuals with smaller ranged of the errors and greater homogeneity and residual standard error with lower values in the classes in general. / A capacidade produtiva é estimada convencionalmente por meio de curvas de sítio calculadas de forma anamórfica ou polimórfica, contudo, estas curvas possuem algumas limitações. Devido a estas limitações, o objetivo deste trabalho foi avaliar a criação de curvas de crescimento para classificação de sítio pelo método de regressão não linear quantílica e compará-las com as curvas geradas pelo método da diferença algébrica. A ba se de dados foi coletada em duas mesorregiões do estado de São Paulo (Macro Metropolitana Paulista e Bauru), com 460 medições em 98 parcelas com períodos distintos em Eucalyptus sp. As curvas de sítio foram ajustadas segundo modelo de Chapman-Richards pelo método da diferença algébrica para curvas anamórficas e polimórficas e regressão não linear quantílica (RNLQ). Os resultados deste trabalho permitiram concluir que as curvas de sítio ajustadas pelo método da RNLQ são superiores às curvas geradas pelo método da diferença algébrica pela análise gráfica dos resíduos com menor amplitude dos erros e maior homogeneidade e erro padrão residual com menores valores nas classes em geral.

Em um contexto de analise de dados de sobrevivência univariados ou multivariados, dados de tempos de falha caracterizam-se pela possibilidade de poderem ser censurados. Embora comum na pratica, a censura impede o uso de alguns procedimentos estatisticos covencionais o que vem motivando, em especial apos a publicacao do artigo de Cox (1972), o desenvolvimento de metodos estatisticos nessa area. Uma linha de estudo recente e a de que, em algumas situacoes, a variavel resposta esteja sendo inuenciada por variaveis latentes, variaveis estas que sao usadas, em um sentido estatistico, para descreverem efeitos geneticos ou ambientais compartilhados pelos indivduos ou, ainda, covariaveis nao consideradas no estudo. Nesse trabalho, enfase e dada aos modelos de sobrevivencia que consideram tempos de falha multivariados e variaveis latentes. Esses tempos aparecem quando, por exemplo, cada individuo em estudo esta sujeito a diversos eventos ou, quando existe um agrupamento natural ou artificial o qual induz dependencia entre os tempos dos individuos do mesmo grupo. Modelos com variaveis latentes em que tais tempos de falha ocorrem em intervalos de tempo, ou seja, em um contexto de censura intervalar sao especialmente considerados nesse trabalho. O modelo de fragilidade gama para dados de sobrevivencia com censura intervalar e proposto, nesse trabalho, como um criterio para a selecao de bovinos. Como uma alternativa para esta selecao, o modelo de curvas de crescimento com efeitos aleatorios e tambem considerado. Para a estimacao dos parametros envolvidos em ambos os modelos propostos, programas computacionais sao apresentados. Uma abordagem Bayesiana e considerada no processo de estimação sendo, o metodo de Markov chain Monte Carlo (MCMC) utilizado e as distribuicoes a posteriori obtidas, usando-se o amostrador de Gibbs. O modelo de fragilidade gama com censura intervalar e o de curvas de crescimento com efeitos aleatorios sao comparados por meio de um estudo de simulação. Para ilustrar ambos os modelos propostos, estudos com bovinos das racas Nelore e Canchim são utilizados. / In a context of univariate or multivariate survival data analysis, failure times data are characterized by the possibility to be censored. Although common in practice, censoring precludes the use of some conventional statistical procedures and it has been motivating, specially after the publication of the Cox's paper (1972), the development of statistical methods in this area. A recent topic of study is concerned with some situations where the response variable is in uenced by latent variables which are used in a statistical sense to describe genetic or environmental efects shared by individuals or also covariates not considered in the study. In this work emphasis is given to survival models which consider multivariate failure times and latent variables. Such times occur when, for instance, each individual under study is exposed to several events or when there is a natural or artificial clustering that causes dependence among times of those individuals at the same cluster. Models with latent variables where such failure times lie in intervals of time, i.e. in an interval censored context are specially considered in this work. The gamma frailty interval censored survival model is proposed in this work as a selection criterion for cattle. As an alternative selection criterion the growth curves model with random efects is also considered. To estimate the involved parameters in both proposed models, computational programs are presented. A Bayesian approach is considered in the estimation process so that the Markov chain Monte Carlo (MCMC) method is used and the posterior distributions are obtained using Gibbs sampling. The gamma frailty interval-censored survival model and the growth curves model with random efects are compared using a simulation study. To illustrate both proposed models studies with Nelore and Canchim cattle are used.

Introdução: Não há curvas de crescimento satisfatórias para lactentes pré-termo de muito baixo peso (PTMBP) até dois anos de idade corrigida (IC), considerando todos os avanços na assistência neonatal ocorridos nas últimas duas décadas. Objetivo: Elaborar curvas de peso, comprimento e perímetro cefálico até dois anos de IC para uma coorte de lactentes PTMBP; comparar as curvas dos adequados (AIG) e dos pequenos para a idade gestacional (PIG). Método: Uma coorte de lactentes PTMBP admitidos na Unidade de Tratamento Intensivo Neonatal do nosso serviço até 24 horas após nascimento entre novembro/2003 até setembro/2005 foi estudada até dois anos de IC. Lactentes com malformações maiores, síndromes cromossômicas, infecções congênitas e aqueles com menos de três revisões nos primeiros dois anos ambulatório de seguimento foram excluídos. Peso, comprimento e perímetro cefálico foram aferidos rotineiramente até 2 anos de IC. O estudo foi aprovado pelo Comitê de Ética e Pesquisa da Instituição. Resultados: Peso, comprimento e perímetro cefálico foram obtidos de 117 recémnascidos PTMBP (51 AIG e 66 PIG) e foram elaboradas curvas de crescimento para lactentes AIG e PIG. As curvas de peso, comprimento e perímetro cefálico de lactentes AIG e PIG têm o mesmo formato (p=0,211; p=0,193; p=0,463, respectivamente). As médias do peso, comprimento e perímetro cefálico com 40 semanas, 12 meses e 24 meses de IC são significativamente superiores entre lactentes AIG (p<0,01, Mixed Effect Models). Conclusão: As curvas de crescimento obtidas através desse estudo longitudinal são adequadas para monitorização do crescimento pós-natal de pré-termos de muito baixo peso AIG e PIG até 2 anos de IC. / Background: There are no satisfactory growth charts for very low birth weight (VLBW) infants from hospital discharge up to two years corrected age that take in consideration all the changes that occurred in neonatal care in the last twenty years. Objectives: To obtain weight, length and head circumference growth charts up to 2 year corrected age (CA) for a cohort of VLBW infants and, also to compare appropriate (AGA) and small (SGA) for gestational age growth curves. Methods: A cohort of VLBW infants admitted to our NICU up to 24 hours after birth from November 2003 through September 2005, and discharged from hospital was studied up to 2 years CA. Infants with major malformations, chromosomal syndromes, congenital infections (STORCH group), and those that had less than 3 appointments in the follow up clinic in the first two years were excluded. Weight, length, and head circumference were measured monthly up to 2 years CA. Results: Mean weight. Length, and head circumference were obtained from 117 newborns (51 AGA and 66 SGA). Growth curves for AGA and SGA infants were obtained. The weight, length, and head circumference growth curves had the same shape for AGA and SGA infants (p=0.211; p=0.193; p=0.463, respectively). Mean weight, length and head circumference at 40 weeks, 12 months and 24 months CA were significantly higher in AGA than in SGA infants (p<0.01, Mixed effect models). Conclusion: Growth curves obtained in this longitudinal study are adequate for monitoring post-natal growth of AGA and SGA VLBW infants.

La qualité des interactions mère–enfant est un excellent prédicteur du fonctionnement socio-émotionnel de l’enfant. Cependant, relativement peu est connu de l’évolution de cette qualité relationnelle dans le temps et encore moins de l’influence de cette évolution sur le développement de l’enfant. De plus, les études ont rarement considéré les interactions mère–enfant sous un angle véritablement dyadique, incluant les contributions de la mère et de l’enfant. À l’aide d’analyses multiniveaux, cette étude vise à décrire la trajectoire développementale de la qualité des interactions dyadiques mère–enfant lorsque l’enfant est âgé de 2 à 7 ans et à investiguer les associations entre cette trajectoire et le fonctionnement socio-émotionnel de l’enfant à 8 ans. La qualité des interactions de 233 dyades mère–enfant a été évaluée à l’aide de séquences de jeu de 10 minutes, filmées lorsque l’enfant était âgé de 2, 4 et 7 ans. À 8 ans, le fonctionnement socio-émotionnel de l’enfant a été rapporté par un sous-échantillon de 171 enseignants. Les analyses révèlent que la pente de la trajectoire des interactions mère–enfant est légèrement mais significativement négative entre 2 et 7 ans. Les enfants dont la qualité des interactions avec leur mère décline de façon moins prononcée entre 2 et 7 ans montrent moins de problèmes intériorisés à 8 ans, indépendamment de la qualité initiale des interactions à 2 ans. Les enfants qui ont une meilleure qualité d’interactions initiale avec leur mère à 2 ans montrent moins de problèmes extériorisés et plus de comportements prosociaux à 8 ans, indépendamment du déclin subséquent de la qualité relationnelle. Les résultats suggèrent que les niveaux initiaux et l’évolution subséquente sont deux aspects distincts de la qualité relationnelle mère–enfant pouvant avoir des incidences indépendantes sur le développement socio-émotionnel de l’enfant. / Research shows that the quality of mother–child interactions is a reliable predictor of child subsequent socio-affective functioning. Yet, relatively little is known about the evolution of this relational quality over time, and even less about how changes in relational quality may influence the course of child development. Therefore, this study aimed to describe the trajectory of quality of mother–child interactions between ages 2 and 7 and investigate the associations between this trajectory and child socio-affective functioning at age 8. The quality of interactions of 233 mother–child dyads was assessed during 10-minute sequences of structured play when children were aged 2, 4, and 7 years. Child socio-affective functioning was reported by a subsample of 171 teachers when children were aged 8. The results showed that the average slope describing the trajectory of quality of mother–child interactions was slightly yet significatively negative. Children who experienced a slower decrease in the quality of interactions with their mother from 2 to 7 years showed less internalizing behavior problems in second grade according to their teacher, over and above the initial quality of mother–child interactions. In addition, children who benefited from higher-quality interactions with their mother at 2 years showed more prosocial behaviors and less externalizing behavior problems in second grade according to their teacher, above and beyond the decrease in the quality of those interactions over time. The findings suggest that although normative developmental changes may lead to slight average decreases in the quality of interactions of mother–child dyads between toddlerhood and early school age, children who benefit from higher-quality interactions with their mother in toddlerhood as well as across toddlerhood and early school age are better adjusted socioemotionally in middle childhood.

The problem of segmenting linearly ordered data is frequently encountered in time-series analysis, computational biology, and natural language processing. Segmentations obtained independently from replicate data sets or from the same data with different methods or parameter settings pose the problem of computing an aggregate or consensus segmentation. This Segmentation Aggregation problem amounts to finding a segmentation that minimizes the sum of distances to the input segmentations. It is again a segmentation problem and can be solved by dynamic programming. The aim of this contribution is (1) to gain a better mathematical understanding of the Segmentation Aggregation problem and its solutions and (2) to demonstrate that consensus segmentations have useful applications. Extending previously known results we show that for a large class of distance functions only breakpoints present in at least one input segmentation appear in the consensus segmentation. Furthermore, we derive a bound on the size of consensus segments. As show-case applications, we investigate a yeast transcriptome and show that consensus segments provide a robust means of identifying transcriptomic units. This approach is particularly suited for dense transcriptomes with polycistronic transcripts, operons, or a lack of separation between transcripts. As a second application, we demonstrate that consensus segmentations can be used to robustly identify growth regimes from sets of replicate growth curves.

Contexte: Le retard de croissance intra-utérin (RCIU) désigne l’incapacité du fœtus à atteindre son potentiel de croissance déterminé génétiquement en raison de diverses causes. Il est défini le plus souvent par un poids de naissance inférieur au 10ème percentile pour l’âge gestationnel sur les courbes néonatales. Ce travail de thèse a comme objectif de répondre aux questions non-résolues sur la définition et les conséquences du RCIU dans le contexte de la grande prématurité: (1) Quelle est la meilleure définition du RCIU à utiliser pour identifier les enfants à risque ? (2) Quels sont les risques de mortalité et de morbidités néonatales respiratoires et neurologiques associés au RCIU et existe-t-il des interactions avec les pathologies de la grossesse responsables de cette naissance très prématurée ? (3) Quel est l’impact du RCIU sur le devenir neuro-développemental à 2 ans, en particulier chez les enfants nés extrêmement prématurément ? Méthodes: Nous avons utilisé deux sources de données. L’étude MOSAIC (Models for OrganiSing Access to Intensive Care for Very Preterm Babies in Europe) est une étude européenne en population qui porte sur l’ensemble des naissances survenues entre 22 et 31 semaines d’aménorrhée en 2003 dans dix régions européennes. Les enfants ont été suivis jusqu’à la sortie d’hospitalisation (population d’étude : 4525 enfants). La deuxième source est une cohorte d’enfants nés avant 27SA qui ont été hospitalisés dans le service de réanimation néonatale à l'hôpital de Port-Royal de 1999 à 2008 et qui ont eu un examen pédiatrique et une évaluation selon l’échelle de Brunet-Lézine qui inclut quatre domaines du développement global de l’enfant : la motricité globale, la motricité fine, le langage et l’interaction sociale (445 enfants admis, 268 enfants suivis à 2 ans). Résultats: Dans les deux populations, les risques de décès et de dysplasie broncho-pulmonaire étaient plus élevés pour les enfants ayant un poids de naissance <10éme percentile des courbes néonatales, mais également pour des enfants avec un poids plus élevé (entre le 10éme et le 24éme percentile des courbes néonatales ou <10ème percentile des courbes fœtales). Par contre, il n’y avait pas de lien entre les complications neurologiques et le faible poids, ni d’interaction avec les pathologies de la grossesse. Le RCIU était associé à un risque élevé du retard neurocognitif à deux ans d’âge corrigé chez les extrêmes prématurés, surtout dans le domaine de la motricité fine et de l’interaction sociale mais pas dans le domaine du langage et de la motricité globale. Nous n’avons pas trouvé d’association entre le RCIU et le risque d’infirmité motrice cérébrale à deux ans d’âge corrigé. Conclusions: L’utilisation du 10ème percentile des courbes néonatales n’est pas adaptée pour identifier l’impact du RCIU chez les grands prématurés ; l’utilisation de multiples seuils ou de courbes de croissance fœtale est nécessaire. Le RCIU accroit les risques de mortalité et de dysplasie broncho-pulmonaire, mais n’est pas associé aux lésions cérébrales sévères ; ces associations sont observées dans différents contextes périnatals (pathologies vasculaires et infectieuses, et naissances à des âges gestationnels très précoces). Le RCIU représente un facteur pronostic défavorable pour le neuro-développement à moyen terme. Nos résultats soulèvent de nouvelles questions sur le suivi adapté pour les enfants ayant un RCIU après leur sortie de l’hôpital et aussi sur les éventuels mécanismes biologiques pouvant expliquer les liens entre le RCIU avec une morbidité respiratoire et certains domaines du développement neurocognitif à moyen terme. / Background: Intrauterine growth restriction (IUGR) refers to the inability of the fetus to achieve its genetically determined growth potential due to various causes. Most often, it is defined by a birth weight less than the 10th percentile for gestational age using neonatal growth curves. This thesis aims to answer unresolved questions about the definition and consequences of IUGR in the context of very preterm birth: (1) what is the best definition of IUGR for identifying children at risk? (2) What are the risks of mortality and neonatal respiratory and neurological morbidity associated with IUGR and are there interactions with the underlying pregnancy complications responsible for the very preterm birth? (3) What is the impact of IUGR on neurodevelopmental at 2 years, especially for children born extremely preterm ? Methods: We used two data sources. The MOSAIC study (Models for Organising Access to Intensive Care for Very Preterm Babies in Europe) is a European population-based study that included all births occurring between 22 and 31 weeks of gestation in 2003 in ten European regions. The children were followed until hospital discharge (study population = 4525 infants). The second source is a cohort of children born before 27 weeks of GA who were hospitalized in the neonatal intensive care unit at the Port Royal Hospital from 1999 to 2008 and had a pediatric examination and Brunet-Lézine (BL) neurodevelopmental assessment at 2 years of corrected age (445 children in the cohort, 268children followed at 2 years). The BL assessment includes four areas of child development: gross motor, fine motor, language and social interaction skills. Results: In both populations, the risk of death and bronchopulmonary dysplasia were higher for children with a birth weight <10th percentile of neonatal growth curves but also for children with a higher birth weight (between the 10th and the 24th percentile of neonatal growth curves or <10th percentile of fetal growth curves). In contrast, there was no link between neurological complications and low birth weight and no interactions with pregnancy complications. IUGR was associated with neurocognitive delay among extremely preterm children evaluated at two years of corrected age, especially for fine motor and social interaction skills, but not for language and gross motor skills. We did not find any association between IUGR and the risk of cerebral palsy at two years of corrected age. Conclusions: The use of the 10th percentile of neonatal growth curves is not suitable for identifying the impact of IUGR in very preterm infants; using higher thresholds or fetal growth curves is necessary. IUGR increased the risks of mortality and bronchopulmonary dysplasia, but was not associated with severe brain damage; these associations are observed in multiple clinical contexts (vascular and infectious pregnancy complications, and births at very early gestational ages). IUGR is a risk factor for poor medium-term neuro-development. Our results raise new questions about the appropriate surveillance for children with IUGR after discharge from the hospital and also about possible biological mechanisms that could explain the relationship between IUGR and respiratory morbidity and neurocognitive development.