• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 57
  • 26
  • 8
  • 3
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 128
  • 128
  • 45
  • 23
  • 21
  • 18
  • 18
  • 18
  • 14
  • 11
  • 11
  • 11
  • 9
  • 9
  • 9
  • 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.
91

Odchov plůdku piskoře pruhovaného (Misgurnus fossilis) v umělých podmínkách / Rearing of weatherfish (Misgurnus fossilis) fry in artificial condition

FRANTA, Pavel January 2017 (has links)
The aim of the M.Sc. thesis was to verify possibility of weaning weatherfish larvae (Misgurnus fossilis) from the live food to the dry starter mixture using the method of co-feeding. The experiment included 3 control groups (starved control no feeding; negative control fed exclusively with dry starter mixture; positive control fed exclusively with live food) and 10 experimental groups with 5 different dates of termination of co-feeding period (at the age 13, 18, 23, 28 and 33 days post-hatching dPH) and different duration of co-feeding period (1 and 7 days). The experiment lasted from the 6 dPH, when mixed feeding was iniciated, until the age 48 dPH at the temperature of 17,8 +- 0,7 °C. The effects of termination and duration of co-feeding period upon continuous survival, morphometric and gravimetric characteristics, ratio of macrobiogenic elements and gross caloric value in somatic tissues of larvae/juveniles were evaluated. Continuous survival, morphometric and gravimetric characteristics and total content of carbon and nitrogen in somatic tissues of larvae/juveniles were increasing with extending dates of termination of co-feeding period. The rearing of weatherfish larvae was accompanied by the marked decline of survival in the period 13 20 dPH, regardless of selected diet regimes in individual groups. Within all fed groups, the worst results of continuous survival and growth were recorded in the negative control as well as groups with date of co-feeding period termination at age 13 dPH. All individuals in these groups died at age 41 dPH. At the end of the experiment, the highest values of continuous survival were achieved in the positive control as well as groups with dates of co-feeding period termination at age 23, 28 and 33 dPH, respectively. There was no significant statistical difference among these groups. Very good results in terms of morphometric and gravimetric characteristics were achieved in the groups with dates of co-feeding period termination at age 28 and 33 dPH, respectively. However, only in group with date of co-feeding period termination at age 33 dPH were achieved comparable values of morphometric characteristics with the positive control. The exception formed only values of the body height as well as dry and wet weights which were significantly higher in the positive control compared to other fed groups. The duration of the co-feeding period (either 1 or 7 days) did not affect any of the monitored characteristics. The results of the present thesis also show that the weatherfish fry best prospers on live food and, on the contrary, fry can not be reared using dry starter mixture as a sole food source. To sum up, among all tested groups that use co-feeding, only weaning of larvae with the date of co-feeding termination at age 33 dPH could be advised. In such condition the continuous survival rate as well as lenght growth reach comparable values with group exclusively fed by live food.
92

Toda boa mãe deve... : governamento das maternidades para a constituição de infâncias saudáveis e normais

Santos, Cláudia Amaral dos January 2009 (has links)
Le but de cette recherche est d'étudier comment le livre La vie de bébé, peut-être le plus grand et le plus connu manuel de l'enfance au Brésil, écrit par le pédiatre Rinaldo de Lamare, favorise ou a encouragé des biopolitiques adressées aux mères sur la constitution de l'enfance d'une façon saine et normale. Je tiens à souligner que l'importance de l'analyse de ce manuel a joué /joue un rôle éducatif, en enseignant des mères et des pères comment agir avec leurs enfants, c'est-à-dire comment doivent-ils les nourrir, quels types d'ambiances et des jouets ils doivent leur fournir de manière à produire des subjectivités, des identités et des savoirs. Pour ce faire, la théorie sur les études culturelles a été utilisé à partir d'un regard post-structuraliste, ainsi que les études de Foucault, en particulier les notions de biopolitique, de gouvernement, de savoir/pouvoir et de discipline. La 17e (1963) et la 41e (2002) éditions ont été utilisées comme matériel de l'analyse dont l„objectif est de souligner quelles stratégies discursives ont été utilisées par l'auteur du livre, un médecin avec beaucoup de connaissance médicale notamment sur la pédiatrie, pour conduire le comportement maternel et paternel; quels savoirs et pouvoirs mis en circulation dans la subjectivité des parents ont été utilisés pour la promotion des enfants sains et en bonne santé; comment le Manuel ici considéré se constitue comme une technologie pour le gouvernement des familles et de l'enfance depuis près de sept décennies; à travers quelles stratégies l'expert promouvait des biopolitiques pour les mères; comment caractérisait-on les sujets enfantins considérés normaux et anormaux et quels étaient les modèles de famille, de mère, de père, de l'éducation des enfants élus dans cette publication . De l'analyse, on a vérifié la force du discours de la psychologie comme une façon de rendre les mères subjectives; l'exaltation de l'allaitement maternel dans les dernières décennies comme le seul moyen pour nourrir le bébé physiquement et « sur son plan émotif »; la centralité de la mère dans la vie du bébé et son rôle comme la responsable de tout ce qui se produit à l'enfant; l'adresse de la publication aux mères hétérosexuels, mariés, blanches, issues des classes moyenne et aisée et des zones urbaines, bien que les pères soient également cités dans les dernières éditions comme étant des figures importantes pour le bébé et, enfin, la vision évolutive du développement normal de l'enfant dans la publication étudiée. / Essa pesquisa tem por objetivo investigar como o livro "A Vida do Bebê", talvez o maior e mais conhecido manual de infância do Brasil, escrito pelo pediatra brasileiro Rinaldo De Lamare, promove/promoveu biopolíticas dirigidas às mães para a constituição de infâncias saudáveis e normais. Ressalto o quanto o manual analisado desempenhou/desempenha uma função pedagógica, ensinando mães e pais a como agir com suas/seus filhas/filhos, como devem alimentá-los, que ambientes e brinquedos lhes devem proporcionar, assim produzindo subjetividades, identidades e saberes. Para a realização da análise, foram utilizados, como referencial teórico, os Estudos Culturais, a partir de um olhar pós-estruturalista, e os estudos de Foucault, principalmente os conceitos de biopolítica, governamento, saber/poder e disciplina. Como material de análise foram utilizadas duas edições do manual, a saber, a 17ª edição (de 1963) e a 41ª edição (de 2002), procurando-se enfatizar por meio de quais estratégias discursivas o autor do livro, investido do saber médico, em específico o pediátrico, conduzia as condutas maternas e paternas; quais os saberes e os poderes colocados em circulação na subjetivação materna e paterna para a promoção de crianças normais e saudáveis; como o manual aqui analisado constitui-se como tecnologia para o governo das famílias e das infâncias ao longo de quase sete décadas e através de que estratégias o especialista promovia biopolíticas dirigidas às mães; como eram caracterizados os sujeitos infantis tidos como normais e anormais e quais eram os modelos de família, mãe, pai, educação e criança promovidos na publicação. A partir da análise verificou-se a força do discurso da psicologia como forma de subjetivar as mães; a exaltação da amamentação nas últimas décadas como única forma de alimentar física e "emocionalmente" o bebê; a centralidade da mãe na vida do bebê, sendo esta responsabilizada por tudo que ocorrer com a criança; o endereçamento da publicação a mães heterossexuais, casadas, brancas, de classe média e alta e urbanas, embora nas últimas edições os pais tenham sido mais citados como também importantes para o bebê; e, por fim, a visão evolutiva do desenvolvimento da criança normal na publicação ora objeto de estudo. / This work aims at investigating how the book "A Vida do Bebê", probably the largest and major children's guide in Brazil, written by Brazilian paediatrician Rinaldo de Lamare, has encouraged biopolicies targeted to mothers for normal healthy early lives. I highlight to what extent the analysed guide has played its instructive role, teaching parents how to behave with their children, how to feed them, which environment and toys they should provide them, thus producing subjectivities, identities and knowledge. To conduct the analysis we have used as a theoretical referential the Cultural Studies from a poststructuralist perspective, and Foucauldian studies, particularly concepts of biopolicy, government, knowledge/power and discipline. We have used as analysis materials two issues of the guide 17th edition (1963) e 41st edition (2002), seeking to emphasise on which discursive strategies the author used as a doctor, specifically a paediatrician, to guide parents' behaviours; which pieces of knowledge and power were circulating in parents' subjectification to promote normal healthy children; how the analysed guide has been a tool to govern families and children throughout nearly seven decades, and which strategies the specialist encouraged biopolicies targeted to mothers; how infant-subjects were regarded normal and abnormal, and which were the models of family, mother, father, education and child provided in the book. With the analysis we have checked the strength of the psychological discourse as a way to subjectify mothers; extolling breast-feeding late decades as the only way to physically and 'emotionally' feed the baby; the mother's centrality in the baby's life when she is blamed for everything occurring to the child; the sending of the book for homosexual, married, white, high- and middle-class, and urban mothers, though in late editions fathers have also been mentioned as significant for the baby; and finally the evolutionary vision for the normal child's development in the book which is now the object of this work.
93

Toda boa mãe deve... : governamento das maternidades para a constituição de infâncias saudáveis e normais

Santos, Cláudia Amaral dos January 2009 (has links)
Le but de cette recherche est d'étudier comment le livre La vie de bébé, peut-être le plus grand et le plus connu manuel de l'enfance au Brésil, écrit par le pédiatre Rinaldo de Lamare, favorise ou a encouragé des biopolitiques adressées aux mères sur la constitution de l'enfance d'une façon saine et normale. Je tiens à souligner que l'importance de l'analyse de ce manuel a joué /joue un rôle éducatif, en enseignant des mères et des pères comment agir avec leurs enfants, c'est-à-dire comment doivent-ils les nourrir, quels types d'ambiances et des jouets ils doivent leur fournir de manière à produire des subjectivités, des identités et des savoirs. Pour ce faire, la théorie sur les études culturelles a été utilisé à partir d'un regard post-structuraliste, ainsi que les études de Foucault, en particulier les notions de biopolitique, de gouvernement, de savoir/pouvoir et de discipline. La 17e (1963) et la 41e (2002) éditions ont été utilisées comme matériel de l'analyse dont l„objectif est de souligner quelles stratégies discursives ont été utilisées par l'auteur du livre, un médecin avec beaucoup de connaissance médicale notamment sur la pédiatrie, pour conduire le comportement maternel et paternel; quels savoirs et pouvoirs mis en circulation dans la subjectivité des parents ont été utilisés pour la promotion des enfants sains et en bonne santé; comment le Manuel ici considéré se constitue comme une technologie pour le gouvernement des familles et de l'enfance depuis près de sept décennies; à travers quelles stratégies l'expert promouvait des biopolitiques pour les mères; comment caractérisait-on les sujets enfantins considérés normaux et anormaux et quels étaient les modèles de famille, de mère, de père, de l'éducation des enfants élus dans cette publication . De l'analyse, on a vérifié la force du discours de la psychologie comme une façon de rendre les mères subjectives; l'exaltation de l'allaitement maternel dans les dernières décennies comme le seul moyen pour nourrir le bébé physiquement et « sur son plan émotif »; la centralité de la mère dans la vie du bébé et son rôle comme la responsable de tout ce qui se produit à l'enfant; l'adresse de la publication aux mères hétérosexuels, mariés, blanches, issues des classes moyenne et aisée et des zones urbaines, bien que les pères soient également cités dans les dernières éditions comme étant des figures importantes pour le bébé et, enfin, la vision évolutive du développement normal de l'enfant dans la publication étudiée. / Essa pesquisa tem por objetivo investigar como o livro "A Vida do Bebê", talvez o maior e mais conhecido manual de infância do Brasil, escrito pelo pediatra brasileiro Rinaldo De Lamare, promove/promoveu biopolíticas dirigidas às mães para a constituição de infâncias saudáveis e normais. Ressalto o quanto o manual analisado desempenhou/desempenha uma função pedagógica, ensinando mães e pais a como agir com suas/seus filhas/filhos, como devem alimentá-los, que ambientes e brinquedos lhes devem proporcionar, assim produzindo subjetividades, identidades e saberes. Para a realização da análise, foram utilizados, como referencial teórico, os Estudos Culturais, a partir de um olhar pós-estruturalista, e os estudos de Foucault, principalmente os conceitos de biopolítica, governamento, saber/poder e disciplina. Como material de análise foram utilizadas duas edições do manual, a saber, a 17ª edição (de 1963) e a 41ª edição (de 2002), procurando-se enfatizar por meio de quais estratégias discursivas o autor do livro, investido do saber médico, em específico o pediátrico, conduzia as condutas maternas e paternas; quais os saberes e os poderes colocados em circulação na subjetivação materna e paterna para a promoção de crianças normais e saudáveis; como o manual aqui analisado constitui-se como tecnologia para o governo das famílias e das infâncias ao longo de quase sete décadas e através de que estratégias o especialista promovia biopolíticas dirigidas às mães; como eram caracterizados os sujeitos infantis tidos como normais e anormais e quais eram os modelos de família, mãe, pai, educação e criança promovidos na publicação. A partir da análise verificou-se a força do discurso da psicologia como forma de subjetivar as mães; a exaltação da amamentação nas últimas décadas como única forma de alimentar física e "emocionalmente" o bebê; a centralidade da mãe na vida do bebê, sendo esta responsabilizada por tudo que ocorrer com a criança; o endereçamento da publicação a mães heterossexuais, casadas, brancas, de classe média e alta e urbanas, embora nas últimas edições os pais tenham sido mais citados como também importantes para o bebê; e, por fim, a visão evolutiva do desenvolvimento da criança normal na publicação ora objeto de estudo. / This work aims at investigating how the book "A Vida do Bebê", probably the largest and major children's guide in Brazil, written by Brazilian paediatrician Rinaldo de Lamare, has encouraged biopolicies targeted to mothers for normal healthy early lives. I highlight to what extent the analysed guide has played its instructive role, teaching parents how to behave with their children, how to feed them, which environment and toys they should provide them, thus producing subjectivities, identities and knowledge. To conduct the analysis we have used as a theoretical referential the Cultural Studies from a poststructuralist perspective, and Foucauldian studies, particularly concepts of biopolicy, government, knowledge/power and discipline. We have used as analysis materials two issues of the guide 17th edition (1963) e 41st edition (2002), seeking to emphasise on which discursive strategies the author used as a doctor, specifically a paediatrician, to guide parents' behaviours; which pieces of knowledge and power were circulating in parents' subjectification to promote normal healthy children; how the analysed guide has been a tool to govern families and children throughout nearly seven decades, and which strategies the specialist encouraged biopolicies targeted to mothers; how infant-subjects were regarded normal and abnormal, and which were the models of family, mother, father, education and child provided in the book. With the analysis we have checked the strength of the psychological discourse as a way to subjectify mothers; extolling breast-feeding late decades as the only way to physically and 'emotionally' feed the baby; the mother's centrality in the baby's life when she is blamed for everything occurring to the child; the sending of the book for homosexual, married, white, high- and middle-class, and urban mothers, though in late editions fathers have also been mentioned as significant for the baby; and finally the evolutionary vision for the normal child's development in the book which is now the object of this work.
94

O estresse precoce como um dos determinantes do uso abusivo de substâncias psicoativas: revisão integrativa / The Early Life Stress as a determinant of the abusive use of psicoactive substances: An integrative review

Larissa Bessani Hidalgo Gimenez 12 June 2015 (has links)
Trata-se de uma revisão integrativa da literatura com o objetivo de identificar, sistematizar e analisar as evidências científicas que corroborem que ter sofrido Estresse Precoce, mensurado pelo instrumento Childhood Trauma Questionnaire (CTQ), é um fator determinante no uso e abuso de substâncias psicoativas na adolescência e vida adulta. A busca foi realizada em agosto de 2014 nas bases de dados: PubMed, Web of Science, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) e Psycinfo, e utilizou-se o limite dos estudos indexados nos últimos 10 anos. Para as buscas nas bases de dados eletrônicas foram utilizadas combinações entre descritores controlados e palavras chaves relacionadas ao uso de substâncias psicoativas, estresse precoce e CTQ adaptadas para cada base de dados, as quais resultaram em 1114 estudos. Com a utilização dos filtros de idiomas Inglês, Espanhol e Português, somente artigos originais e publicações a partir do ano de 2003 até 18 de Agosto de 2014 o número de referências totais foram de 439. Após retirar os artigos duplicados em mais de uma base de dados, o número total de referências elegíveis para este estudo foi de 359. Após leitura de títulos e resumos foram selecionados para leitura na íntegra 157 estudos. Após leitura na íntegra foram excluídos aqueles textos que não respondiam a questão de pesquisa, sendo eleitos para esta revisão 08 artigos. Para extração dos dados foi utilizado um instrumento validado (URSI). A análise da descrição dos estudos foi realizada com base no instrumento STROBE, metodologia e delineamento das pesquisas foram analisadas com assessoria estatística. A análise dos dados foi descritiva e dividida em subcategorias: Estresse Precoce e Uso de Substâncias Psicoativas na Adolescência; Estresse Precoce e a Diferença Entre os Gêneros; Estresse Precoce e a Relação com Estresse e Depressão na Vida Adulta; Estresse Precoce e as Estratégias de Enfrentamento (Coping) na Vida Adulta; Estresse Precoce e o Álcool: a droga mais utilizada e porta de entrada para outras substâncias psicoativas. A partir dos estudos incluídos nessa revisão, foi possível identificar fatores que evidenciam que ter sofrido Estresse Precoce tem como um desfecho o uso abusivo de álcool e outras substâncias psicoativas na adolescência e vida adulta, em combinação com outros fatores ambientais e genéticos que influenciam o início do uso e posterior abuso das mesmas / This is an integrative literature review in order to identify, classify and analyze the scientific evidence supporting that have suffered Early Life Stress, measured by the Childhood Trauma Questionnaire (CTQ), is a determining factor in the use and abuse of psychoactive substances in adolescence and adulthood. The search was conducted in August 2014 in the databases: PubMed, Web of Science, Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) and Psycinfo, and used the limit of the indexed studies in the last 10 years. For searches of electronic databases were used combinations of controlled descriptors and keywords related to substance abuse, early life stress and CTQ, adapted to each database, resulting in 1114 studies. With the use of the filters: English, Spanish and Portuguese language, only original articles and publications from the year 2003 until August 18, 2014, the total number of references were 439. After removing duplicate items in more than one database, the total number of references eligible for this study was 359. After reading titles and abstracts, were selected for full reading 157 studies. In the full texts, were excluded those who did not respond to the research question, being elected to this review 08 articles. For data extraction was used a validated instrument (URSI). The analysis of the description of the studies was based on the STROBE instrument. The methodology and design of the researches were analyzed with statistical advice. Data analysis was descriptive and divided into subcategories: Early Life Stress and Psychoactive Substance Use in Adolescence; Early Life Stress and the Difference Between the Genders; Early Life Stress and the Relationship with Stress and Depression in Adulthood; Early Life Stress and Coping Strategies in Adulthood; Early Life Stress and Alcohol: the most widely used drug and gateway to other psychoactive substances. From the studies included in this review, it was possible to identify factors that Early Life Stress is an outcome of the alcohol and other psychoactive abuse in adolescence and adulthood, in combination with other environmental and genetic factors, that influence the beginning of use and later abuse of them
95

Toda boa mãe deve... : governamento das maternidades para a constituição de infâncias saudáveis e normais

Santos, Cláudia Amaral dos January 2009 (has links)
Le but de cette recherche est d'étudier comment le livre La vie de bébé, peut-être le plus grand et le plus connu manuel de l'enfance au Brésil, écrit par le pédiatre Rinaldo de Lamare, favorise ou a encouragé des biopolitiques adressées aux mères sur la constitution de l'enfance d'une façon saine et normale. Je tiens à souligner que l'importance de l'analyse de ce manuel a joué /joue un rôle éducatif, en enseignant des mères et des pères comment agir avec leurs enfants, c'est-à-dire comment doivent-ils les nourrir, quels types d'ambiances et des jouets ils doivent leur fournir de manière à produire des subjectivités, des identités et des savoirs. Pour ce faire, la théorie sur les études culturelles a été utilisé à partir d'un regard post-structuraliste, ainsi que les études de Foucault, en particulier les notions de biopolitique, de gouvernement, de savoir/pouvoir et de discipline. La 17e (1963) et la 41e (2002) éditions ont été utilisées comme matériel de l'analyse dont l„objectif est de souligner quelles stratégies discursives ont été utilisées par l'auteur du livre, un médecin avec beaucoup de connaissance médicale notamment sur la pédiatrie, pour conduire le comportement maternel et paternel; quels savoirs et pouvoirs mis en circulation dans la subjectivité des parents ont été utilisés pour la promotion des enfants sains et en bonne santé; comment le Manuel ici considéré se constitue comme une technologie pour le gouvernement des familles et de l'enfance depuis près de sept décennies; à travers quelles stratégies l'expert promouvait des biopolitiques pour les mères; comment caractérisait-on les sujets enfantins considérés normaux et anormaux et quels étaient les modèles de famille, de mère, de père, de l'éducation des enfants élus dans cette publication . De l'analyse, on a vérifié la force du discours de la psychologie comme une façon de rendre les mères subjectives; l'exaltation de l'allaitement maternel dans les dernières décennies comme le seul moyen pour nourrir le bébé physiquement et « sur son plan émotif »; la centralité de la mère dans la vie du bébé et son rôle comme la responsable de tout ce qui se produit à l'enfant; l'adresse de la publication aux mères hétérosexuels, mariés, blanches, issues des classes moyenne et aisée et des zones urbaines, bien que les pères soient également cités dans les dernières éditions comme étant des figures importantes pour le bébé et, enfin, la vision évolutive du développement normal de l'enfant dans la publication étudiée. / Essa pesquisa tem por objetivo investigar como o livro "A Vida do Bebê", talvez o maior e mais conhecido manual de infância do Brasil, escrito pelo pediatra brasileiro Rinaldo De Lamare, promove/promoveu biopolíticas dirigidas às mães para a constituição de infâncias saudáveis e normais. Ressalto o quanto o manual analisado desempenhou/desempenha uma função pedagógica, ensinando mães e pais a como agir com suas/seus filhas/filhos, como devem alimentá-los, que ambientes e brinquedos lhes devem proporcionar, assim produzindo subjetividades, identidades e saberes. Para a realização da análise, foram utilizados, como referencial teórico, os Estudos Culturais, a partir de um olhar pós-estruturalista, e os estudos de Foucault, principalmente os conceitos de biopolítica, governamento, saber/poder e disciplina. Como material de análise foram utilizadas duas edições do manual, a saber, a 17ª edição (de 1963) e a 41ª edição (de 2002), procurando-se enfatizar por meio de quais estratégias discursivas o autor do livro, investido do saber médico, em específico o pediátrico, conduzia as condutas maternas e paternas; quais os saberes e os poderes colocados em circulação na subjetivação materna e paterna para a promoção de crianças normais e saudáveis; como o manual aqui analisado constitui-se como tecnologia para o governo das famílias e das infâncias ao longo de quase sete décadas e através de que estratégias o especialista promovia biopolíticas dirigidas às mães; como eram caracterizados os sujeitos infantis tidos como normais e anormais e quais eram os modelos de família, mãe, pai, educação e criança promovidos na publicação. A partir da análise verificou-se a força do discurso da psicologia como forma de subjetivar as mães; a exaltação da amamentação nas últimas décadas como única forma de alimentar física e "emocionalmente" o bebê; a centralidade da mãe na vida do bebê, sendo esta responsabilizada por tudo que ocorrer com a criança; o endereçamento da publicação a mães heterossexuais, casadas, brancas, de classe média e alta e urbanas, embora nas últimas edições os pais tenham sido mais citados como também importantes para o bebê; e, por fim, a visão evolutiva do desenvolvimento da criança normal na publicação ora objeto de estudo. / This work aims at investigating how the book "A Vida do Bebê", probably the largest and major children's guide in Brazil, written by Brazilian paediatrician Rinaldo de Lamare, has encouraged biopolicies targeted to mothers for normal healthy early lives. I highlight to what extent the analysed guide has played its instructive role, teaching parents how to behave with their children, how to feed them, which environment and toys they should provide them, thus producing subjectivities, identities and knowledge. To conduct the analysis we have used as a theoretical referential the Cultural Studies from a poststructuralist perspective, and Foucauldian studies, particularly concepts of biopolicy, government, knowledge/power and discipline. We have used as analysis materials two issues of the guide 17th edition (1963) e 41st edition (2002), seeking to emphasise on which discursive strategies the author used as a doctor, specifically a paediatrician, to guide parents' behaviours; which pieces of knowledge and power were circulating in parents' subjectification to promote normal healthy children; how the analysed guide has been a tool to govern families and children throughout nearly seven decades, and which strategies the specialist encouraged biopolicies targeted to mothers; how infant-subjects were regarded normal and abnormal, and which were the models of family, mother, father, education and child provided in the book. With the analysis we have checked the strength of the psychological discourse as a way to subjectify mothers; extolling breast-feeding late decades as the only way to physically and 'emotionally' feed the baby; the mother's centrality in the baby's life when she is blamed for everything occurring to the child; the sending of the book for homosexual, married, white, high- and middle-class, and urban mothers, though in late editions fathers have also been mentioned as significant for the baby; and finally the evolutionary vision for the normal child's development in the book which is now the object of this work.
96

Estresse precoce e alterações do eixo hipotálamo-pituitária-adrenal (HPA) na depressão. / Early Life Stress and alterations of the Hypothalamic-Pituitary-Adrenal (HPA) axis in depression.

Cristiane von Werne Baes 30 March 2012 (has links)
Introdução: Diversos estudos sugerem que o estresse nas fases iniciais de desenvolvimento pode induzir alterações persistentes na capacidade do eixo Hipotálamo-Pituitária-Adrenal (HPA) em responder ao estresse na vida adulta. O desequilíbrio do cortisol tem sido identificado como um correlato biológico dos transtornos depressivos. Essas anormalidades parecem estar relacionadas às mudanças na capacidade dos glicocorticóides circulantes em exercer seu feedback negativo na secreção dos hormônios do eixo HPA por meio da ligação aos receptores mineralocorticóides (RM) e glicocorticóides (RG) nos tecidos do eixo HPA. Devido à grande variedade de estressores, assim como os diferentes subtipos de depressão, os achados dos estudos atuais têm sido inconsistentes. Dessa forma, necessitando de mais estudos para que se possa elucidar os mecanismos envolvidos na associação entre o Estresse Precoce (EP) e o desenvolvimento de quadros depressivos. Objetivo: O objetivo deste estudo é avaliar a correlação entre Estresse Precoce e alterações no eixo Hipotálamo-Pituitária-Adrenal e na função dos receptores glicocorticóides e mineralocorticóides em pacientes depressivos. Metodologia: Foram recrutados inicialmente 30 sujeitos divididos em dois grupos: grupo de pacientes com diagnóstico de episódio depressivo atual (n=20) e grupo de controles (n=10). Posteriormente os pacientes foram divididos em outros dois grupos de acordo com o EP, compondo a amostra final por três grupos: grupo de pacientes depressivos com presença de EP (n=13), grupo de pacientes depressivos com ausência de EP (n=7) e grupo de controles (n=10). Os pacientes foram avaliados por meio de Entrevista Clínica de acordo com os critérios diagnósticos do DSM-IV, para a confirmação do diagnóstico. Para avaliação da gravidade dos sintomas depressivos foi aplicada a Escala de Depressão de Hamilton (HAM-D21), sendo incluídos apenas pacientes com HAM-D21 17. A presença de EP foi confirmada através da aplicação do Questionário Sobre Traumas na Infância (QUESI). Foram utilizados também a Escala de Avaliação de Depressão de Montgomery-Asberg (MADRS), o Inventário de Depressão de Beck (BDI), o Inventário de Ansiedade de Beck (BAI), a Escala de Ideação Suicida de Beck (BSI), a Escala de Desesperança de Beck (BHS), a Escala Hospitalar de Ansiedade e Depressão (HAD) e a Escala de Impulsividade de Barratt (BIS-11) para a avaliação de sintomas psiquiátricos. A avaliação endócrina foi controlada por placebo, cego por parte dos controles e pacientes, não randomizado, com desenho de medidas repetidas, onde os efeitos da Fludrocortisona (0.5 mg) e da Dexametasona (0.5 mg) foram avaliados através do cortisol salivar e plasmático. A secreção de cortisol plasmático e salivar foi avaliada nos sujeitos, após a administração de uma cápsula de Placebo, Fludrocortisona e Dexametasona às 22hs do dia anterior. O cortisol salivar foi coletado às 22h, ao acordar, 30 e 60 minutos após acordar e antes da coleta plasmática, nos dias seguintes após os desafios. Resultados: Na amostra de pacientes depressivos e controles, encontramos níveis significativamente menores de cortisol salivar ao acordar após a administração de Placebo nos pacientes depressivos comparados aos controles. Encontramos também uma tendência dos pacientes apresentarem níveis maiores de cortisol salivar ao acordar do que os controles após a administração de Dexametasona. Quando avaliado o cortisol após a administração de Fludrocortisona, os pacientes apresentaram níveis significativamente menores de cortisol salivar 30 minutos após acordar e na Área Sob a Curva (AUC) do que os controles. Além disso, encontramos também uma tendência dos pacientes depressivos apresentarem níveis menores de cortisol salivar 60 minutos após acordar do que os controles. Quando comparados entre pacientes depressivos com presença e ausência de EP e controles, encontramos uma tendência dos pacientes depressivos com ausência de EP apresentarem níveis menores de cortisol salivar ao acordar após Placebo do que os controles. As médias dos níveis de cortisol salivar ao acordar não diferiram entre os pacientes com presença de EP e os controles e entre os pacientes do grupo presença e ausência de EP. Com relação aos níveis de cortisol salivar após a administração de Dexametasona entre pacientes depressivos com presença e ausência de EP e controles, os pacientes depressivos com ausência de EP apresentaram níveis significativamente maiores de cortisol salivar ao acordar do que os controles. Encontramos também uma tendência dos pacientes com ausência de EP apresentarem níveis maiores de cortisol salivar ao acordar do que os pacientes com presença de EP, porém não foram encontradas diferenças significativas entre os pacientes com presença de EP e os controles. Conclusão: Nossos dados demonstram uma hipoatividade do eixo HPA nos pacientes depressivos. Além disso, estes achados sugerem que esta desregulação do eixo HPA se deva em parte a uma diminuição da sensibilidade dos RG e uma hiperativação dos RM nos pacientes depressivos. No entanto, quando comparados pacientes depressivos com presença e ausência de Estresse Precoce, os desafios com agonistas seletivos como a Dexametasona (agonista RG) e a Fludrocortisona (agonista RM) não foram capazes de detectar esta diferença fisiopatológica e distinguir entre os diferentes tipos de psicopatologia. Dessa forma, estes resultados sugerem que estudos com um agonista misto (RG/RM) como a Prednisolona teriam potencial para distinguir os pacientes depressivos com presença de Estresse Precoce. / Introduction: Several studies suggest that stress in early stages of development can induce persistent changes in the ability of the Hypothalamic-Pituitary-Adrenal (HPA) axis to respond to stress in adulthood. The imbalance of cortisol has been identified as a biological correlate of depressive disorders. These abnormalities seem to be related to changes in the ability of circulating glucocorticoids to practice their negative feedback on the secretion of HPA axis hormones through connecting to the mineralocorticoid receptor (MR) and glucocorticoid (GR) in the tissues of HPA axis. Due to the wide variety of stressors, as well as the different subtypes of depression, the findings of current studies have been inconsistent. Thus, more studies need to be able to elucidate the mechanisms involved in the association between Early Life Stress (ELS) and the development of depression. Objective: The objective this study is to evaluate the correlation between of Early Life Stress and changes in Hypothalamic-Pituitary-Adrenal axis and at receptors function glucocorticoid and mineralocorticoid in depressive patients. Methodology: We recruited 30 subjects initially divided into two groups: patients with current depressive episode (n =20) and control group (n = 10) Subsequently, patients were divided into two groups according to the ELS, making the final sample of three groups: depressive patients with ELS (n =13) group of depressive patients without ELS (n=7) and control group (n=10). Patients were evaluated by clinical interview according to the diagnostic criteria of DSM-IV to confirm the diagnosis. To evaluate the severity of depressive symptoms was applied to the Hamilton Depression Scale (HAM-D21), and included only patients with HAM-D21 17. The presence of ELS was confirmed by the Childhood Trauma Questionnaire (CTQ). We also used the Depression Rating Scale Montgomery-Asberg (MADRS), the Beck Depression Inventory (BDI), the Beck Anxiety Inventory (BAI), the Scale for Suicide Ideation Beck (BSI), the Scale Beck Hopelessness (BHS), the Hospital Anxiety and Depression Scale (HADS) and the Barratt Impulsiveness Scale (BIS-11) for the assessment of severity psychiatric symptoms. Endocrine evaluation was placebo-controlled, blinded by the patients and controls, non-randomized design with repeated measures, where the effects of Fludrocortisone (0.5 mg) and dexamethasone (0.5 mg) were assessed using salivary cortisol and plasma. The secretion of plasma cortisol and salivary was evaluated in the subjects, after administration of a capsule of Placebo, Fludrocortisone and Dexamethasone to 22hs the previous day. The salivary cortisol was collected at 22h, on waking, 30 and 60 minutes after waking and before plasma collection in the following days after the challenges. Results: In these sample of depressed patients and controls, we found significantly lower levels of salivary cortisol around waking after administration of Placebo in depressed patients than controls. We also found a trend for patients to have higher levels of salivary cortisol than controls on awakening after administration of Dexamethasone. When measured cortisol after administration of Fludrocortisone, patients showed significantly lower levels of salivary cortisol 30 minutes after waking and the Area Under the Curve (AUC) than controls. In addition, we also found a tendency for depressed patients showed lower levels of salivary cortisol 60 minutes after awakening than controls. When compared between depressed patients with and without ELS and controls, we found a tendency for depressed patients without ELS presented lower levels of salivary cortisol on awakening after Placebo than controls. The mean salivary cortisol levels on waking did not differ between patients with ELS and controls and between patients with and without ELS. The levels of salivary cortisol after Dexamethasone administration between depressed patients with and without ELS and controls, depressed patients without ELS had significantly higher levels of salivary cortisol on awakening than controls. We also found a trend for patients without Early Life Stress have higher levels of salivary cortisol upon waking than patients with Early Life Stress, but there were no significant differences between patients with Early Life Stress and controls. Conclusion: Our data show a hypoactivity of the HPA axis in depressed patients. Moreover, these findings suggest that this dysregulation HPA axis is partly due to a decrease the sensitivity of RG and a hyperactivation of MR in patients depressive. However, when compared depressed patients with and without Early Life Stress, the challenges with selective agonists as the Dexamethasone (agonist GR) and Fludrocortisone (agonist MR) were not able to detect this difference pathophysiological and distinguish between the different types of psychopathology. Thus, these results suggest that studies with a mixed agonist (GR/MR) such as Prednisolone have potential to distinguish of depressive patients with Early Life Stress.
97

Análise da Ocorrência de Estresse Precoce em Pacientes Psiquiátricos Adultos / Analysis of the Occurrence of Early Life Stress on Adult Psychiatric Patients.

Camila Maria Severi Martins 27 April 2012 (has links)
Introdução: Evidências recentes indicam que situações de abandono, negligência e abusos são fatores de risco para desencadeamento de psicopatologias na vida adulta. Esta associação ocorre na medida em que eventos traumáticos, nas fases iniciais do desenvolvimento podem desencadear transtornos psiquiátricos graves e incapacitantes no adulto. Objetivo: O presente estudo objetivou avaliar a associação entre a ocorrência e a gravidade do Estresse Precoce (EP) e o desencadeamento de transtornos psiquiátricos em pacientes adultos em seguimento no Hospital Dia do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP-USP). Metodologia: A amostra foi composta por 81 pacientes psiquiátricos avaliados através de Entrevista Clínica, de acordo com os critérios do DSM-IV, para confirmação diagnóstica, divididos em 2 grupos: 58 pacientes com presença de EP e 23 com ausência de EP. A presença de EP foi confirmada através da aplicação do Questionário Sobre Traumas na Infância (QUESI). Os pacientes também foram avaliados quanto à gravidade da sintomatologia psiquiátrica através do Inventário de Depressão de Beck (BDI), Inventário de Ansiedade de Beck (BAI), Escala de Desesperança de Beck (BHS), Escala de Ideação Suicida de Beck (BSI), Escala Hospitalar de Ansiedade e Depressão (HAD) e da Escala de Impulsividade de Barratt (BIS-11). Resultados: Na amostra avaliada, 71.6% dos pacientes sofreram algum tipo grave de EP comparados a 28.4% dos pacientes que não sofreram. Considerando-se os subtipos de Estresse Precoce avaliados, os pacientes com história de trauma apresentaram escores maiores em todos os subtipos de Estresse Precoce em comparação aos pacientes sem história de abuso. A pontuação total do QUESI também foi significativamente diferente 66.05 vs. 34.78 (p<0.001) entre os grupos. A maioria dos pacientes avaliados (n=35; 60.4%) sofreu de 3 a 5 subtipos de Estresse Precoce. Os resultados indicam que o EP está associado principalmente com o desenvolvimento de transtornos de humor e também com o aumento da gravidade dos sintomas psiquiátricos, principalmente dos sintomas depressivos, sintomas de desesperança, de ideação suicida e de impulsividade. Com relação ao diagnóstico de eixo II, o EP está associado com o desenvolvimento de transtorno de personalidade (p=0.03). Pacientes com história de abuso emocional (OR: 5.2; 95% IC, 1.9-13.5), negligência emocional (OR: 4.02; 95% IC, 1.6-10.2) e negligência física (OR: 4.0; 95% IC, 1.6-10.1) apresentam um risco de 4 a 5 vezes maior de desenvolver transtorno de personalidade. Além disso, indivíduos que sofreram abuso físico (OR: 2.46; 95% IC; 0.89-6.78), abuso sexual (OR: 2.87; 95% IC; 0.86-9.57) e negligência física (OR: 2.50; 95% IC; 0.95-6.55) possuem de 2 a 3 vezes mais chances de cometer tentativas de suicídio. Nossos dados também demonstram que entre os subtipos de EP, o abuso emocional foi associado ao desencadeamento de psicopatologias na vida adulta, principalmente com os transtornos depressivos. Além disso, pacientes com presença de abuso emocional, tiveram maior gravidade em todos os sintomas psiquiátricos, tais como: sintomas de depressão, desesperança, ideação suicida, ansiedade e impulsividade. Também foram encontradas correlações positivas entre impulsividade, ideação suicida e desesperança com os escores totais do QUESI. Conclusões: Os dados apontam para a importância do Estresse Precoce como fator desencadeante de transtornos psiquiátricos, bem como indicam que a gravidade do Estresse Precoce está associada com a gravidade dos sintomas psiquiátricos.Dessa forma, há necessidade de mais estudos que avaliem a importância dos subtipos de Estresse Precoce como fator de risco para desencadeamento de psicopatologias graves no adulto. / Introduction: Recent evidences suggest that situations of abandonment, neglect and abuse are risk factors for onset of psychopathology on adulthood. This association occurs in that traumatic events in the early stages of development and may trigger severe and disabling psychiatric disorders in adults. Objective: The present study aimed to evaluate the association between the occurrence and severity of early life stress (ELS) and the development of psychiatric disorders in adult patients of the Day Hospital Unit of the Hospital das Clinicas, Faculty of Medicine of Ribeirão Preto University of São Paulo (HCFMRP- USP). Methodology: The sample was consisted of 81 psychiatric patients evaluated by Clinical Interview according to the DSM-IV criteria for the diagnosis, divided into two groups: 58 patients with presence of ELS and 23 with absence of ELS. The presence of ELS was confirmed by the Childhood Trauma Questionnaire (CTQ). Patients also were evaluated for severity of psychiatric symptoms by the Beck Depression Inventory (BDI), the Beck Anxiety Inventory (BAI), the Beck Hopelessness Scale (BHS), the Beck Scale for Suicide Ideation (BSI), the Hospital Anxiety and Depression Scale (HAD) and the Barratt Impulsiveness Scale (BIS-11). Results: In the sample studied, 71.6% of patients with some type of severe ELS compared to 28.4% of patients without ELS. Considering the subtypes of ELS evaluated, patients with a history of trauma showed higher scores in all subtypes of ELS compared to patients without a history of abuse. The total score of QUESI was also significantly different 66.05 vs. 34.78 (p<0.001) between groups. Most patients (n = 35, 60.4%) suffered 3-5 subtypes of ELS. The results indicate that ELS is associated mainly with the development of mood disorders and also with increasing severity of psychiatric symptoms, especially the depressive symptoms, hopelessness, suicidal ideation and impulsivity. Regarding the diagnosis of axis II, ELS is associated with personality disorder (p=0.03). Patients with emotional abuse (OR: 5.2, 95% CI, 1.9-13.5), emotional neglect (OR: 2.4, 95% CI, 1.6-10.2) and physical neglect (OR: 4.0, 95% CI, 1.6-10.1) at 4-5 fold higher risk of personality disorder. In addition, individuals who suffered physical abuse (OR: 2.46, 95% CI, 0.89-6.78), sexual abuse (OR: 2.87, 95% CI, 0.86-9.57) and physical neglect (OR: 2.50; 95% CI, 0.95-6.55) at 2-3 fold higher to commit suicide attempts. Our data also showed that among the subtypes of ELS, emotional abuse was associated with the onset of psychopathology in adulthood, especially in depressive disorders. Furthermore, patients with presence of emotional abuse, had more severe psychiatric symptoms at all, such as depressive symptoms, hopelessness, suicidal ideation, anxiety and impulsivity. We also found positive correlations between impulsivity, suicide ideation and hopelessness with the total scores of the QUESI. Conclusions: These data demonstrate the importance of ELS as a trigger for psychiatric disorders, and indicate that the severity of ELS is associated with the severity of psychiatric symptoms. Therefore, further studies are needed to assess the importance of subtypes of ELS as a risk factor for onset of severe psychopathology in adults.
98

Où va la jeunesse ? Mouvements et quête alimentaire des juvéniles de procellariiformes durant leur première année en mer / Movements and foraging strategies of juveniles procellariiformes during their first months of independence

Jeudi de Grissac, Sophie 11 October 2016 (has links)
Le stade juvénile chez les animaux demeure souvent une période mystérieuse aux yeux des scientifiques. La survie juvénile est pourtant un facteur déterminant du futur des populations. Les animaux juvéniles sont connus pour leur mortalité importante durant les premiers mois après l’indépendance et leur taux de survie augmente avec l’âge. La théorie suppose d’une part que les juvéniles ont des capacités de survie moindres que celles des adultes. Ils seraient peu efficaces dans leur recherche de nourriture et auraient besoin d’une période d’apprentissage pour être capables de supporter les couts associés à la reproduction. De plus, des facteurs proximaux telles que les fluctuations environnementales et la compétition affectent également la survie des juvéniles. Des études sur les oiseaux terrestres, ont permis d’obtenir de nombreuses informations grâce à la possibilité de faire des observations directes et récemment des études télémétriques. Cependant collecter des données en milieu marin s’avère compliqué, en particulier lorsque l’on s’intéresse aux juvéniles. Les oiseaux marins longévifs ont en commun la longue durée de leur période d’immaturité (jusqu’à plus de 10 ans). Les jeunes, à l’indépendance, se dispersent seuls en mer durant plusieurs années, ne revenant à terre que pour se reproduire une fois adulte. Ainsi, les suivre durant leurs premiers mois afin de comprendre leurs comportements et leur écologie alimentaire constitue un véritable défi. Dans ce contexte, cette thèse a pour objectif d’élucider au moins en partie le mystère de la vie juvénile des oiseaux marins. Grâce à des technologies bio-télémétriques nous avons pu suivre par satellite un large panel de juvéniles de neuf espèces proches d’albatros et pétrels (procellariiformes) se reproduisant dans les Terres Australes et Antarctiques Françaises de l’Océan Austral : les îles Crozet, Kerguelen et Amsterdam. Les trajectoires ont été analysées grâce à différentes méthodes statistiques permettant de décrire les mouvements, le comportement alimentaire et les répartitions spatiales des jeunes après leur envol, le tout en lien avec les conditions environnementales. Les résultats obtenus sont discutés à la lumière de la comparaison avec les adultes des mêmes espèces. Grâce à ce jeu de données j’ai étudié les stratégies de dispersion des jeunes inexpérimentés qui quittent le nid. J’ai montré que ces stratégies ainsi que la proportion d’inné les contrôlant sont très variables selon les espèces et suivent ou non celles des parents selon les espèces. Le taux de variabilité dans les stratégies juvéniles peut refléter leur potentielle plasticité et leur capacité à répondre à des changements de l’environnement et in fine affecter la dynamique des populations. Par ailleurs, l’analyse de trajectoires de juvéniles de grand albatros a révélé qu’en plus de leurs capacités innées ils apprennent très rapidement les compétences de base requises pour survivre en mer puis optimiser leur recherche alimentaire. Cependant des différences perdurent par rapport aux adultes, suggérant que d’autres comportements non-observables (via nos données) nécessitent une période d’apprentissage plus longue. Enfin, quelle que soit la stratégie adoptée, elle semble en partie contrainte par la compétition intraspécifique avec les individus plus âgés puisque les juvéniles limitent celle-ci via une ségrégation spatiale. Ce dernier point souligne le besoin de prendre en compte la répartition spatio-temporelle âge-dépendante des espèces lorsque l’on veut mettre en œuvre des mesures de protection pour ces espèces. Ces travaux apportent de nouvelles connaissances sur plusieurs des aspects majeurs de l’écologie en mer d’individus inexpérimentés cherchant leur nourriture seuls dans un environnement hautement imprévisible. Nous apprenons ici comment de l’instinct et de l’expérience découlent des stratégies de vie juvéniles qui permettent aux oiseaux de survivre dans un environnement inconnu. / The juvenile stage of animals is often much of a mystery to scientists. Moreover, juvenile survival is known to be a strong determinant for the future of a population. Indeed, juvenile animals are known to face high mortality during the first months after independence, with survival rates improving with age. One ultimate hypothesis implies that juveniles have a lower survival rate than adults because of their lack of experience. Thus they are initially poor foragers and require a learning period (immaturity) to improve their efficiency before being able to bear breeding and its associated energetic costs. Proximal factors also influence juvenile survival, such as environmental fluctuations and competition. Studies on terrestrial animals have provided useful information thanks to the possibility of direct observation and, recently, bio-logging technologies. However, collecting data in the marine environment is more difficult, particularly when juveniles are concerned. Long-lived marine species such as seabirds have an extensive immature period extending from a few years up to more than ten years. The offspring of these species will usually leave their natal site and disperse at sea for several years before returning to breed on land, most of the time at their place of birth. This makes it difficult to obtain direct observations, and so documenting their first journey at sea to learn more about their behavioural and foraging ecology is a challenge. In this context, this PhD aims to unravel at least part of the mystery of juvenile seabirds’ early life by investigating the first months at sea of newly fledged individuals from several long-lived species of procellariiformes. Using state of the art advancements in biotelemetry, I was able to follow, at sea, by satellite a large set of juveniles from nine closely related species of albatross and petrel breeding in the French Southern Territories of the Southern Ocean : Crozet, Kerguelen and Amsterdam Islands. Some of these species had never been tracked before. Trajectories were analysed using various new statistical methods that allowed movement strategies, alongside foraging behaviour and spatial distributions, to be described, all in tight link with environmental conditions. The findings were discussed in the light of a comparison with adults of the same species. Using this huge dataset I first examined the dispersal strategies of young birds that had left their nest and were totally independent from their parents. I showed that the strategies, as well as the amount of innate information controlling them are highly variable depending on species. Their movements take them in various habitats following or not the parental strategies. The amount of variability in juvenile strategies is linked to potential plasticity when facing environmental changes. These parameters are related to the history life trait of species, and might affect demography and population dynamics. In addition, by analysing juvenile wandering albatross tracks I showed that although they quickly learn the basics of flight and foraging optimization required to survive at sea, behavioural differences with adults persist in time, suggesting that non-observable behaviours need a longer period of learning and memorisation. Finally, whatever the strategy adopted, it seems to be driven in part by intraspecific competition since juveniles mitigate competition with older birds by segregating spatially. This last point highlights the crucial need of acknowledging age-related distribution when making management decisions to protect seabird populations. This work provides new insights about several major aspects of the at-sea ecology of naïve individuals foraging alone in a highly unpredictable environment. We learn here how instinct followed by experience shape specific early life strategies that allow young birds to deal with environmental conditions and interspecific competition so as to be able to survive.
99

Early-life events and their consequences for adult performance in populations of large herbivores : evolutionary, ecological and demographic perspectives / Les événements de vie précoces et leurs conséquences pour la performance individuelle à l'âge adulte chez les grands mammifères herbivores sauvages : une perspective évolutive, écologique et démographique

Douhard, Mathieu 23 October 2014 (has links)
La variabilité environnementale à laquelle les individus sont constamment exposés est forte. Dans ce contexte, les conditions environnementales en début de vie sont particulièrement importantes puisqu’elles peuvent avoir des conséquences à long terme sur la performance des individus. L’objectif de cette thèse est d’améliorer notre compréhension des effets à long-terme des évènements vécus tôt dans la vie, incluant aussi bien les conditions environnementales que la croissance, sur les traits d’histoire de vie des grands mammifères herbivores. Afin de répondre à cet objectif, nous avons utilisé les suivis à long-terme de cinq populations appartenant à quatre espèces d’ongulés. Dans une première partie, nous avons montré que les conditions environnementales en début de vie peuvent influencer la trajectoire entière de croissance corporelle d’un individu. Ensuite, nous avons cherché à savoir si les effets des conditions environnementales en début de vie sur les traits d’histoire de vie à l’âge adulte représentaient des réponses adaptatives à différents environnements ou résultaient seulement de contraintes développementales dues à une restriction alimentaire. Nous avons répondu à cette question en testant notamment des hypothèses issues du domaine médical en populations sauvages / The environment to which individuals are permanently exposed varies greatly over time. The environmental conditions during early life are particularly important in this context because they can have extraordinary long-term consequences on individual performance. The main goal of this PhD thesis was to improve our understanding of the long-term effects of early-life events, including environmental conditions and growth, on life-history traits of large herbivores. In order to meet this objective, we used detailed long-term data from five populations of four species of ungulates. We highlighted that environmental conditions experienced during early life can influence the entire body growth trajectory of an individual. Then, we investigated whether the long-term effects of early environmental conditions on life-history traits represent adaptive responses to differing environments, or are only a consequence of energetic constraints on development. We aimed to address this issue by testing hypotheses issued from human medicine in wild populations
100

La Terre à l'Archéen. Apport des isotopes de métaux de transition (Zn, Fe) / The Archean Earth as constrained by stable isotopes of transition metal (Zn, Fe)

Pons, Marie-Laure 16 December 2011 (has links)
L’Archéen, de 4 à 2,5 Ga, est la période qui a connu les plus grands bouleversements géologiques et biologiques de l’histoire de la Terre : formation des continents, transition d’une tectonique à composante verticale vers une tectonique des plaques horizontale, apparition de la vie, … Le but de cette thèse est d’étudier les conditions environnementales de la Terre à l’Archéen, par l’analyse des compositions isotopiques de métaux de transition (Fe, Zn) de roches provenant principalement de la province d’Isua au Groenland (3,8 Ga). Après avoir adapté le protocole de séparation du Fe, Cu, Zn à des échantillons riches en Fe, nous avons acquis les données par spectrométrie de masse à source plasma et à multicollection MC-ICPMS. Nous nous sommes d’abord intéressés au processus de serpentinisation de la croûte océanique, réaction produisant à la fois des nutriments pour la vie (CH 4 , H 2 ) et des minéraux catalyseurs (mackinawite) de la formation abiotique d’acides aminés, molécules du vivant. L’affleurement d’Isua comporte une unité ophiolitique présentant les serpentinites les plus anciennes (3.81-3.70 Ga) : leur analyse permet d’appréhender la réaction de serpentinisation à l’Archéen. Les résultats obtenus pour la composition isotopique du zinc dans ces roches et dans des serpentinites modernes ont permis d’établir une correspondance entre le processus de serpentinisation à Isua et la mise en place de volcans de boues de serpentinites à l’aplomb de la fosse des Mariannes. Nous avons ainsi pu identifier Isua comme une zone d’arrière-arc de subduction océanique, lieu d’une serpentinisation produisant des fluides de température variable (100-300°C) et de pH alcalin (9-12). Nous montrons que cette configuration atypique réunissant serpentinisation, fluides alcalins et édifices volcaniques est favorable à l’émergence du vivant. Nous avons ensuite analysé de nombreux échantillons de formations de fer rubané (BIFs), sédiments propres à l’Archéen et au début du Protérozoïque. L’évolution de la composition isotopique du zinc de ces échantillons au cours du temps a permis d’établir une chronologie de l'émersion des continents.Nos résultats sont en faveur d’une émersion débutant il y a 2,9 Ga. Enfin, nos données nous informent sur la colonisation des continents émergés par la vie à 2,6 Ga et sur la pédogenèse de sols archéens comportant un horizon organique. / During the Archean (4 to 2.5 Ga ago), the Earth experienced the biggest changes in terms of geological and biological settings – continental growth, transition from sagduction towards purely horizontal plate tectonics, emergence of life, … The purpose of the present study is to better understand the archean earth environment by measuring the isotopic composition of transition metals – Zn, Fe – of archean rocks. Most of the samples belong to the Isua supracrustal belt, in Greenland, dated 3.8 Ga. The chemical extraction protocol of Fe, Cu, Zn was adapted to our Fe-rich samples and isotopic analyses were conducted by multicollection inductively coupled plasma mass spectrometry. The serpentinization of the oceanic crust produces fuels for life (CH 4 , H 2 ) and mackinawite, which catalyses formation of complex organic compounds. Serpentinization may thus provide a suitable environment for the emergence of the first biomolecules. We analysed the oldest known serpentinites from Isua (3.81-3.70 Ga) to comprehend the archean serpentinization process. The isotopic compositions of zinc reported in this samples and in modern serpentinites attest to a strong similarity between Isua and the Mariana serpentinite mud volcanoes. We identified Isua as an oceanic forearc environment permeated by high-pH (9-12) hydrothermal solutions at medium temperature (100-300°C). We show that such an environment could have fostered the emergence of early life. We also analyzed several banded iron formations (BIF), which are sediments limited to the Archean and Proterozoic. The temporal evolution of these samples' isotopic composition shows a close relationship with the continental freeboard. Our results support the continental emersion starting 2.9 Ga ago. Besides, we identified the life colonization of continents at 2.6 Ga together with pedogenesis of archean soils with an organic horizon.

Page generated in 0.0996 seconds