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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Mecanismos subjacentes ao efeito da manipulação neonatal sobre o vínculo mãe/filhote

Reis, Adolfo Rodrigues January 2014 (has links)
Ao nascerem, os mamíferos não estão com o sistema nervoso plenamente desenvolvido e os primeiros dias de vida representam uma fase crítica para o desenvolvimento desse sistema. De fato, nesta fase o encéfalo está passando por diversos processos fundamentais como organização funcional das redes neurais, proliferação neuronal, migração, diferenciação, além de gliogênese e mielinização. Em ratos, um procedimento simples, como “manipular” os filhotes por alguns minutos durante a primeira semana de vida, pode marcar decisivamente o desenvolvimento do indivíduo. Assim, a manipulação neonatal tem sido muito utilizada para se examinar os mecanismos pelos quais variações ambientais podem afetar o desenvolvimento do filhote. A manipulação neonatal promove uma série de alterações comportamentais e neuroendócrinas que se caracterizam basicamente por uma diminuição do medo e da resposta ao estresse no adulto. Embora muitos autores até caracterizem a manipulação como uma intervenção positiva ela também pode provocar graves déficits em comportamentos sociais e reprodutivos para a prole aparecendo desde o inicio do desenvolvimento e persistindo até a vida adulta. Além de seu efeito sobre os filhotes, estudos tem demostrado que intervenções na prole no período neonatal também afetam de forma duradoura a resposta ao estresse das genitoras, mas este tema ainda é muito pouco explorado pela literatura Portanto, na primeira parte desta tese, iremos estudar os efeitos da manipulação neonatal sobre a formação do vínculo mãe-filhote, tentando associar mudanças no comportamento da mãe ao longo dos 10 primeiros dias pós-parto com a preferencia pelo odor do ninho em filhotes testados no labirinto em Y. Na segunda parte desta tese iremos abordar os efeitos da manipulação sobre a resposta ao estresse agudo e crônico em ratas que tiveram seus filhotes manipulados no período neonatal, para isso submetemos genitoras dos grupos controle e manipulado após o desmame a um dos dois protocolos descritos a seguir: com estresse (estresse por contenção de movimentos 1h/dia por 7 dias) ou sem estresse (nenhuma intervenção após o desmame) e testamos os animais através do teste de nado forçado para observar mudanças na resposta emocional. Também medimos os níveis de BDNF e corticosterona no plasma após o teste e medimos o peso das adrenais para verificar o efeito da manipulação na resposta ao estresse das genitoras Os resultados dessa tese mostram que a manipulação neonatal afeta a estrutura do comportamento maternal, mudando a sequencia e a sincronia do comportamento da mãe com o filhote, o que poderia ser em parte a causa da alteração no comportamento de preferencia pelo odor do ninho observado em animais manipulados, principalmente nas fêmeas. Além disso, observamos que a manipulação afeta de forma duradoura a resposta ao estresse (agudo e crônico) das genitoras, podendo alterar a resposta emocional desses animais e predispor a sintomas do tipo depressivo em resposta ao estresse agudo Esses resultados reforçam a ideia de que o estudo dos efeitos duradouros da manipulação não só nos filhotes, mas também no organismo materno, podem servir como uma importante ferramenta para elaboração de projetos clínicos, visando a exploração da existência de comportamentos similares em humanos. Isso ajudará na elaboração de politicas de saúde publica que visem minimizar os efeitos de eventos adversos acontecidos no inicio da vida sobre a saúde física e mental tanto da mãe quanto da criança. / Mammals are not born with fully developed nervous system, and the first days of life represent a critical stage in the development of this system. In fact, at this stage, the brain is undergoing many fundamental processes such as functional organization of neural networks, neuronal proliferation, migration, differentiation, gliogenesis and myelination. In rats, a simple procedure such as "handling" the pups for a few minutes during the first week of life can decisively mark the development of the individual. Thus, neonatal handling has been widely used to examine the mechanisms by which environmental adversity can affect the development of the pups. Neonatal handling promotes a series of behavioral and neuroendocrine changes that are characterized primarily by a decrease of fear and stress responses in the adult. Although many authors characterize the handling procedure as a positive intervention, it is also associated with severe deficits in social and reproductive behaviors of the offspring that appear early during development and persist into adulthood. Apart from its effect on the pups, studies have shown that interventions in the offspring during the neonatal period can also induce long lasting effects in the maternal stress response, but this subject is still little explored in the literature Therefore, in the first part of this thesis, we will study the effects of neonatal handling on the mother-pups’ bond formation, trying to associate changes in maternal behavior over the first 10 days postpartum with the preference for the odor of the nest in pups tested the Y maze. The second part of this thesis will address the effects of neonatal handling on the acute and chronic stress response in dams that had their pups handled. For this purpose, we submitted mothers of control and manipulated groups after weaning to: stress (restraint 1h/day for 7 days) or no stress (no intervention after weaning) and tested the animals using the forced swim test to observe changes in emotional response. We also measured plasma BDNF and corticosterone levels after the test and the adrenals’ weight to verify the effect of handling on the dam’s stress response. The results of this thesis show that neonatal handling affects the structure of maternal behavior, changing the behavioral sequence and synchrony of the mother with her pups, which could be in part the cause of the altered social behaviors observed in handled pups, especially in females. Moreover, we observed that handling affects the dam´s response to stress (acute and chronic), and may alter the emotional response of the dams increasing the susceptibility to developing psychiatric disorders such as depression at least in response to acute stress These results reinforce the idea that investigating the long lasting effects of handling not only in the young, but also in the dam’s physiology becomes an important tool for the development of clinical studies, aiming at exploring the existence of similar effects in humans. The final goal will be the elaboration of public health policy to minimize the effects of early life adverse events on physical and mental health of both mothers and their children.
272

Analýza variability objemu vajec poláka velkého (\kur{Aythya ferina}) a poláka chocholačky (\kur{Aythya fuligula}) / The analysis of variance egg volume of Common pochard (\kur{Aythya ferina}) and Tufted ducks (\kur{Aythya fuligula})

BAŽANT, Miroslav January 2011 (has links)
I investigated differences in egg volumes for two common species diving ducks ? Common pochard (Aythya ferina) and Tufted ducks (Aythya fuligula). I tested selected reproductive and environmental factors with potential influence on egg volume and sex of embryo in clutches. Further, I examined egg volume in connection with the nest parasitism and compared parasitic and non-parasitic eggs in context of egg volume. I also estimated rate of nest parasitism in studied ducks population.
273

Arquitetura genética do comportamento materno de construção de ninho

Silva, Bruno Sauce 05 August 2010 (has links)
Made available in DSpace on 2016-06-02T20:21:24Z (GMT). No. of bitstreams: 1 3223.pdf: 1875073 bytes, checksum: da879cb2bcfcd8ac244156eec8eca3ad (MD5) Previous issue date: 2010-08-05 / Universidade Federal de Minas Gerais / Genetic architecture of a phenotype represents the total number of genes, independent effects (additivity), the interactions between alleles (dominance and epistasis), and its effects on other phenotypes (pleiotropy). An enormous debate about general types of genetic architectures relates the importance of independent and interactive variation in the adaptive process. Because natural selection reduces additive variation, we expect, of fitness related phenotypes, lesser additive than interactive variation and relatively more genes with moderate effects. Maternal care is a phenotype with enormous importance to fitness. Of the maternal care behaviors, the nest building highlights itself improving pups survival by protection against predators and temperature maintenance. We investigated the genetic architecture of nest building in mice and tested the hypothesis that this behavior has a genetic architecture related to fitness, also verifying possible associations with anxiety and weight. For that, we checked the relation between all phenotypes and tested, using the QTL analysis, the phenotypic association with regions (microsatellites markers) spread about all genome of F2 females at maternal stage from the intercross of inbred strains SM/J and LG/J. We found 23 QTLs which, individually, are associated with phenotypic variation on nest building, weight and anxiety (15 QTLs at the 6 nest building phenotypes). The nest building s individual QTLs have moderate effects (from 4 to 13%), and the numerous epistatic QTLs add to increase this explained variation. There are common regions for nest building with anxiety and weight and, searching for candidate genes, we found genes with effects already described for these phenotypes. Hence, we corroborate our hypothesis of the genetic architecture type related to fitness for nest building behavior, of genes with bigger effects and high interactive variation. The identification of regions associated with maternal care in mice and the knowledge of the related genetic architecture can help in identifying genes for these behaviors in other mammals, and in the comprehension of general patterns in adaptive process and life evolution. / Arquitetura genética de um fenótipo representa o número total de genes, os efeitos independentes (aditividade), as interações entre alelos (dominância e epistasia), e o efeito destes em outros fenótipos (pleiotropia). Um grande debate entre tipos gerais de arquitetura genética está no papel da variação independente e de interações no processo adaptativo. Pela seleção natural reduzir a variação aditiva, esperamos de fenótipos ligados ao fitness menor variação aditiva relativa a variação de interações e genes com efeitos médios relativamente mais comuns. O cuidado materno é um fenótipo com grande importância para o fitness. Dentre os comportamentos de cuidado materno, a construção de ninho destaca-se aumentando a sobrevivência dos filhotes pela proteção contra predadores e manutenção da temperatura. Investigamos a arquitetura genética da construção de ninho em camundongos e testamos a hipótese que esse comportamento tem a arquitetura genética relacionada ao fitness, verificando também possíveis associações com ansiedade e peso. Para isso, checamos as relações entre os fenótipos e testamos, com a análise de QTL, a associação dos fenótipos com regiões (marcadores microssatélites) por todo o genoma de fêmeas F2 em fase materna do intercruzamento das linhagens endogâmicas SM/J e LG/J. Obtivemos 23 QTLs que, individualmente, estão associados com a variação nos fenótipos de construção de ninho, peso e ansiedade (15 QTLs para os 6 fenótipos de construção de ninho). Os QTLs individuais de construção de ninho têm efeitos moderados (de 4 a 13%), e os muitos QTLs epistáticos colaboram aumentando essa variação explicada. Existem regiões em comum para ninho com peso e ansiedade e, na procura de genes candidatos, descobrimos genes já descritos com efeitos nesses fenótipos. Assim, corroboramos a hipótese do tipo de arquitetura genética relacionada ao fitness para o comportamento de construção de ninho, de genes com grandes efeitos e alta variação genética de interações. A identificação de regiões associadas ao cuidado materno em camundongos e o entendimento da arquitetura genética envolvida poderão contribuir na identificação de genes para esses comportamentos em outros mamíferos, e na compreensão do padrão geral do processo adaptativo e da evolução dos seres vivos.
274

Mecanismos subjacentes ao efeito da manipulação neonatal sobre o vínculo mãe/filhote

Reis, Adolfo Rodrigues January 2014 (has links)
Ao nascerem, os mamíferos não estão com o sistema nervoso plenamente desenvolvido e os primeiros dias de vida representam uma fase crítica para o desenvolvimento desse sistema. De fato, nesta fase o encéfalo está passando por diversos processos fundamentais como organização funcional das redes neurais, proliferação neuronal, migração, diferenciação, além de gliogênese e mielinização. Em ratos, um procedimento simples, como “manipular” os filhotes por alguns minutos durante a primeira semana de vida, pode marcar decisivamente o desenvolvimento do indivíduo. Assim, a manipulação neonatal tem sido muito utilizada para se examinar os mecanismos pelos quais variações ambientais podem afetar o desenvolvimento do filhote. A manipulação neonatal promove uma série de alterações comportamentais e neuroendócrinas que se caracterizam basicamente por uma diminuição do medo e da resposta ao estresse no adulto. Embora muitos autores até caracterizem a manipulação como uma intervenção positiva ela também pode provocar graves déficits em comportamentos sociais e reprodutivos para a prole aparecendo desde o inicio do desenvolvimento e persistindo até a vida adulta. Além de seu efeito sobre os filhotes, estudos tem demostrado que intervenções na prole no período neonatal também afetam de forma duradoura a resposta ao estresse das genitoras, mas este tema ainda é muito pouco explorado pela literatura Portanto, na primeira parte desta tese, iremos estudar os efeitos da manipulação neonatal sobre a formação do vínculo mãe-filhote, tentando associar mudanças no comportamento da mãe ao longo dos 10 primeiros dias pós-parto com a preferencia pelo odor do ninho em filhotes testados no labirinto em Y. Na segunda parte desta tese iremos abordar os efeitos da manipulação sobre a resposta ao estresse agudo e crônico em ratas que tiveram seus filhotes manipulados no período neonatal, para isso submetemos genitoras dos grupos controle e manipulado após o desmame a um dos dois protocolos descritos a seguir: com estresse (estresse por contenção de movimentos 1h/dia por 7 dias) ou sem estresse (nenhuma intervenção após o desmame) e testamos os animais através do teste de nado forçado para observar mudanças na resposta emocional. Também medimos os níveis de BDNF e corticosterona no plasma após o teste e medimos o peso das adrenais para verificar o efeito da manipulação na resposta ao estresse das genitoras Os resultados dessa tese mostram que a manipulação neonatal afeta a estrutura do comportamento maternal, mudando a sequencia e a sincronia do comportamento da mãe com o filhote, o que poderia ser em parte a causa da alteração no comportamento de preferencia pelo odor do ninho observado em animais manipulados, principalmente nas fêmeas. Além disso, observamos que a manipulação afeta de forma duradoura a resposta ao estresse (agudo e crônico) das genitoras, podendo alterar a resposta emocional desses animais e predispor a sintomas do tipo depressivo em resposta ao estresse agudo Esses resultados reforçam a ideia de que o estudo dos efeitos duradouros da manipulação não só nos filhotes, mas também no organismo materno, podem servir como uma importante ferramenta para elaboração de projetos clínicos, visando a exploração da existência de comportamentos similares em humanos. Isso ajudará na elaboração de politicas de saúde publica que visem minimizar os efeitos de eventos adversos acontecidos no inicio da vida sobre a saúde física e mental tanto da mãe quanto da criança. / Mammals are not born with fully developed nervous system, and the first days of life represent a critical stage in the development of this system. In fact, at this stage, the brain is undergoing many fundamental processes such as functional organization of neural networks, neuronal proliferation, migration, differentiation, gliogenesis and myelination. In rats, a simple procedure such as "handling" the pups for a few minutes during the first week of life can decisively mark the development of the individual. Thus, neonatal handling has been widely used to examine the mechanisms by which environmental adversity can affect the development of the pups. Neonatal handling promotes a series of behavioral and neuroendocrine changes that are characterized primarily by a decrease of fear and stress responses in the adult. Although many authors characterize the handling procedure as a positive intervention, it is also associated with severe deficits in social and reproductive behaviors of the offspring that appear early during development and persist into adulthood. Apart from its effect on the pups, studies have shown that interventions in the offspring during the neonatal period can also induce long lasting effects in the maternal stress response, but this subject is still little explored in the literature Therefore, in the first part of this thesis, we will study the effects of neonatal handling on the mother-pups’ bond formation, trying to associate changes in maternal behavior over the first 10 days postpartum with the preference for the odor of the nest in pups tested the Y maze. The second part of this thesis will address the effects of neonatal handling on the acute and chronic stress response in dams that had their pups handled. For this purpose, we submitted mothers of control and manipulated groups after weaning to: stress (restraint 1h/day for 7 days) or no stress (no intervention after weaning) and tested the animals using the forced swim test to observe changes in emotional response. We also measured plasma BDNF and corticosterone levels after the test and the adrenals’ weight to verify the effect of handling on the dam’s stress response. The results of this thesis show that neonatal handling affects the structure of maternal behavior, changing the behavioral sequence and synchrony of the mother with her pups, which could be in part the cause of the altered social behaviors observed in handled pups, especially in females. Moreover, we observed that handling affects the dam´s response to stress (acute and chronic), and may alter the emotional response of the dams increasing the susceptibility to developing psychiatric disorders such as depression at least in response to acute stress These results reinforce the idea that investigating the long lasting effects of handling not only in the young, but also in the dam’s physiology becomes an important tool for the development of clinical studies, aiming at exploring the existence of similar effects in humans. The final goal will be the elaboration of public health policy to minimize the effects of early life adverse events on physical and mental health of both mothers and their children.
275

Řešení problematiky syndromu prázdného hnízda / A Solution to the Problem of Empty Nest Syndrome

KOUBOVÁ, Petra January 2009 (has links)
This thesis deals with the problem of empty nest. The theoretical part is devoted to the description of this phenomenon. The first chapter deals with the term of empty nest, with the time span when it occurs, and with the cause and consequences for all family members. In the second chapter the thesis discusses the difference between the present and the past of this syndrome, and the tendencies of young people to this problem. The third chapter brings actual suggestions for solution of the empty nest syndrome. The praktical part contains the results of dialogues, which were carried out with respondents over 40. years of age. The awareness of the empty nest syndrome among the respondents is good this is one of the results. Another one is the fact that the respondents have had personal experince with the syndrome or they know about it from their friends families. A very important result was that the respondents agreed with the start of a new service which would provide help to parents with the empty nest syndrome. The practical part also contains a project, focused on the implementation of the service to parents with this syndrome.
276

Informed habitat choice in the heterogeneous world: ecological implications and evolutionary potential

Tolvanen, J. (Jere) 08 May 2018 (has links)
Abstract Animals live in a heterogeneous world where threats and abundance and quality of resources vary across space and time. Heterogeneity induces uncertainty in decisions that animals must make, e.g., where to breed. Adaptive decisions may be facilitated by personally collecting information on the quality of the environment and by observing the behaviour and success of other individuals. Such social information use is common in nature. I investigate information use in relation to ecological threats (brood parasites, nest predators) and long-term information use in breeding site choice in the wild. Moreover, I examine the genetic basis of social cue use in breeding site choice. I demonstrated experimentally that open-nesting hosts of a brood parasite, the common cuckoo (Cuculus canorus), can cue on cuckoo vocalizations to estimate cuckoo abundance and avoid breeding sites with high perceived parasitism risk. Another experiment showed that pied flycatchers (Ficedula hypoleuca) derive predation risk information from the fates of heterospecific nests, can associate the information with a nest site characteristic and generalize the association to own nest site choice. However, apparently only young females that made their choice quickly used the information in nest site choice. Pied flycatchers were further observed to collect habitat quality information based on the old nest contents during the post-breeding period. Use of the information in breeding site choice in the following spring varied between sex and age groups as well as geographically. Some birds integrated the post-breeding period information with the information available during settlement suggesting sequential social information use. Finally, quantitative genetic analyses revealed low additive genetic variances and genetic heritabilities of social cue use in breeding site choice in a collared flycatcher (Ficedula albicollis) population. These results demonstrate new aspects of informed habitat choice in wild animals which have important implications for species coexistence and community ecology, parasite-host coevolution, between-species niche dynamics and evolution. Between-individual variation in information use is highlighted throughout the thesis and warrants further research. The evolutionary potential of information use appears low, but more studies in other populations and species are needed. / Tiivistelmä Eläimet elävät ympäristössä, jossa resurssit ja uhat vaihtelevat ajallisesti ja alueellisesti. Tämä vaihtelu aiheuttaa epävarmuutta eläinten päätöksentekoon, kuten pesimäpaikan valintaan. Hyödyllisten päätösten tekoa voi edesauttaa keräämällä tietoa ympäristön laadusta itsenäisesti tai seuraamalla muiden yksilöiden käytöstä ja menestystä. Tällainen sosiaalisen informaation käyttö on yleistä eläinkunnassa. Tutkin informaation käyttöä ekologisten uhkien (pesäloiset, -pedot) suhteen ja pitkäaikaista informaation käyttöä pesimäpaikan valinnassa luonnonpopulaatioissa. Lisäksi selvitän pesimäpaikan valintaan liittyvän informaation käyton geneettistä periytyvyyttä. Selvitin kokeellisesti, että pesäloisen, käen (Cuculus canorus), isäntälajit voivat käyttää käkien ääntelyä vihjeenä alueellisesta loisintauhasta ja siten välttää korkean uhan alueita pesimäpaikan valinnassa. Toisessa kokeessa havaittiin kirjosieppojen (Ficedula hypoleuca) keräävän tietoa pesäpetouhasta toisen lajin pesätuhojen kautta, kykenevän yhdistämään tiedon erilliseen pesäpaikan ominaisuuteen ja käyttämään tätä assosiaatiota omassa pesäpaikan valinnassa. Kuitenkin vain nuoret naaraat, jotka tekivät valintansa nopeasti, käyttivät kyseistä informaatiota valinnassaan. Lisäksi havaitsin kirjosieppojen keräävän tietoa ympäristön laadusta pesinnän jälkeen vanhojen pesäsisältöjen avulla. Kyseisen tiedon käyttö pesimäpaikan valinnassa seuraavana keväänä vaihteli lintujen sukupuolen ja iän suhteen, kuin myös alueellisesti. Osa linnuista yhdisti pesimäpaikan valinnassaan aikaisempaa, pesinnän jälkeen kerättyä tietoa ja keväällä saatavilla olevaa sosiaalista informaatiota. Geneettinen analyysi viittasi pesimäpaikan valintaan liittyvän informaation käytön alhaiseen additiivisen geneettisen varianssin määrään ja siten alhaiseen geneettiseen periytyvyyteen sepelsiepolla (Ficedula albicollis). Väitöskirjani tulokset kuvaavat uudenlaisia informaation käytön muotoja eläinten pesimäpaikan valinnassa. Havainnot auttavat ymmärtämään pesälois-isäntä rinnakkaisevoluutiota, lajien välisiä vuorovaikutuksia, lajiyhteisöjen toimintaa ja evoluutiota. Yksilöiden välinen vaihtelu informaation käytössä näyttää olevan yleistä, ja lisätutkimuksen tarpeessa. Informaation käytön evolutiivinen potentiaali näyttää rajalliselta, mutta lisätutkimukset eri populaatioilla ja lajeilla ovat tarpeen.
277

Déterminants de la survie et de la dispersion de reproduction par une approche capture-marquage-recapture chez l'Hirondelle bicolore au Québec / Determinants of survival and breeding dispersal by a capture-recapture approach in Tree swallow in Québec

Lagrange, Paméla 09 April 2015 (has links)
En Amérique du Nord, la superficie des monocultures utilisatrices d'intrants tels que des fertilisants et des pesticides couvre aujourd'hui 85% des surfaces agricoles et autant de pâturages ont disparu en 20 ans afin de répondre aux besoins de l'homme. Ces changements d'usage des terres ont profondément transformé le paysage et altéré la biodiversité des agro-écosystèmes. Parmi les espèces d'oiseaux champêtres, les insectivores aériens tel l'Hirondelle bicolore, Tachycineta bicolor, ici étudiée, présente un fort taux de déclin des effectifs, reflétant probablement une dégradation des agro-écosystèmes. Les mécanismes biologiques à l'origine de ce déclin sont encore méconnus ainsi que les patrons de dispersion chez les passereaux migrateurs. Le présent travail vise à étudier les effets environnementaux sur les traits individuels (survie et succès reproducteur) et la dispersion de reproduction (probabilité de disperser et taux d'occupation des sites de reproduction) chez l'Hirondelle bicolore. Pour ce faire, 2200 reproducteurs et 8000 oisillons ont été bagués entre 2004 et 2013 et suivis en reproduction pendant 10 ans sur une aire d'étude au Sud du Québec, laquelle est composée de 40 sites et couvre une mosaïque de paysages agricoles hétérogènes. Le développement d'un nouveau modèle de capture-marquage-recapture, flexible d'utilisation, a permis de réduire les biais d'estimation des probabilités de survie et de dispersion de l'espèce. Cette approche a permis de tester l'effet de plusieurs variables en lien avec la qualité de l'habitat, l'information publique et les caractéristiques individuelles sur la variabilité des paramètres de dispersion, de survie et de succès reproducteur au niveau individuel. Les milieux cultivés intensivement associés à la présence du Moineau domestique, Passer domesticus, un compétiteur pour les cavités de reproduction, diminuent jusqu'à 19% la survie des mâles. Les femelles sont quant à elles affectées par le coût de la reproduction, qui est d'autant plus grand en milieu intensif qu'il y a présence de moineaux et une disponibilité moindre en ressources alimentaires. Pour autant, la décision de disperser n'est pas affectée par les conditions environnementales que ce soit par la présence de compétiteurs ou la qualité du milieu, et ne dépasse pas les 4% chez les mâles. Les femelles dispersant jusqu'à 14 fois plus s'appuient sur leur expérience personnelle pour décider de disperser. Un échec de reproduction augmente jusqu'à 7 fois la probabilité de disperser et pour la première fois chez une espèce à courte durée de vie, nous montrons que la probabilité de disperser est augmentée l'année suivant une première dispersion. Ces patrons de dispersion sont stables dans le temps. La dispersion apparait donc comme un processus coûteux, comparé à la fidélité au site, qui apparaît comme un phénotype minoritaire dans la population. Elle répond à des conditions défavorables de reproduction. Enfin, ce travail montre l'utilisation de l'information publique (densité en partenaires, productivité en jeunes l'année précédente) dans la décision de s'établir sur un site et ce, une fois que la décision de disperser est amorcée. La présence de moineaux et la proportion de cultures intensives dans un rayon proche participent également à la sélection d'un site. D'après mes résultats, le milieu intensif contribuerait au déclin de l'Hirondelle bicolore. / In North America, monoculture areas using high inputs of fertilizers and pesticides cover 85% of agricultural lands, and as many pastures disappeared in the past 20 years to satisfy human food needs. These land-use changes have deeply transformed landscapes and altered the biodiversity of agro-ecosystems. Among farmland birds, aerial insectivores such as Tree swallow, Tachycineta bicolor, studied here show a high rate of decline in their abundance, partly reflecting the degradation of agro-ecosystems where they breed. Biological mechanisms leading to the decline and dispersal patterns in migratory passerines are still poorly known. The present work quantifies the environmental effects on Tree swallow individual traits (survival, reproductive success) and breeding dispersal (probability to disperse and occupation rates of breeding sites). Between 2004 and 2013, 2200 breeders and 8000 chicks were ringed and monitored during 10 breeding seasons on a study area composed of 40 sites and covering a mosaic of heterogeneous agricultural landscapes in southern Québec. The development of a new, flexible capture-mark-recapture model has reduced estimate bias of survival and dispersal probabilities of Tree swallows. This approach allowed to assess the effect of several variables linked to habitat quality, public information and individual characteristics on dispersal, survival and reproductive success parameters of individuals. Within intensively cultivated landscapes associated to the presence of a nest site competitor, the House sparrow, Passer domesticus, male survival is up to 19% lower. Females are affected by the cost of reproduction, especially in intensive landscapes where House sparrows and found and where food resources and nest site appear limited. Dispersal probability is not affected by environmental conditions either through the presence of House sparrows or habitat quality, and is restricted to 4% in males. Females, which disperse up to 14 times more than males, base their decision on their personal experience. Breeding failure increases up to 7 times the probability to disperse and for the first time in a short-lived species, I show that dispersal likelihood increases if the individual has dispersed in the previous year. These dispersal patterns are stable in time. Dispersal appears as a costly process compared to site fidelity and is a minority phenotype in the population. It appears an answer to unfavorable condition for reproduction. Finally, this work shows the use of public information (partners density, fledglings productivity the previous year) on the decision to settle on a site and this, after the dispersal decision has been initiated. The presence of House sparrows and the proportion of intensive areas near nestboxes are used as information to select a breeding site. Based on my findings, agricultural intensification likely plays a role in the decline of Tree swallow populations.
278

Gestion et place du CROUS dans le logement étudiant / Social housing for students in france : a dilemma between equity and efficiency

Ducray, François 19 December 2013 (has links)
Promulguée en 2001, la LOLF assigne aux CROUS l'objectif d'améliorer les conditions de vie et de travail des étudiants sous la contrainte d'une optimisation des coûts. En s'intéressant à l'évolution du parc CROUS et à sa gestion, la première partie de la thèse essaie de concilier la question du bâti (rénovation, réhabilitation, reconstruction des cités universitaires/normes des nouvelles constructions) et celle du financement (partage aide à la pierre/allocation logement, durée de prêt, taux d'intérêt, ….).La seconde partie met en parallèle le logement et d'autres aspects de la politique publique en faveur des étudiants. L'incidence du logement sur l'égalité des opportunités scolaires et la difficulté de trouver un logement locatif nous interpellent sur l'étendue des solutions alternatives. L'étude de leurs freins nous conduit à une péréquation de l'offre CROUS. A côté de la difficulté à trouver un logement et des attentes étudiantes, le gain de pouvoir d’achat des résidents du CROUS est à rapprocher des aides sociales aux étudiants. Une comparaison entre une allocation universelle d'études et un ajustement à la marge du système des bourses conclut la thèse. / Since 2001, LOLF reinforced New Public Management in French public sector. Now, social housing for students (CROUS) must combine social goals with a cost-effective approach.First of all, we study building and try to explain the upkeep’s cost heterogeneity. We deduce strategies about restoration and constructing. Then, an optimal structure of finance between housing vouchers and housing public funds is defined.In the second part, this thesis deals with housing policies and students living. Firstly, we introduce two topics:-How housing can affect college choice?-Are co-rent, subsidies to promote lower rents or boarding school good alternatives? Why?Secondly, econometric tests examine search difficulties on housing market. We induce public investment and territorial equalization of CROUS housing. A comparison between progressive grants for students and universal basic income closes the work.
279

Habitat Use of the Key Largo Woodrat (Neotoma floridana smalli)

Barth, Lauren J 12 November 2014 (has links)
Key Largo woodrats are an endangered subspecies with an extremely limited habitat. This study sought to understand woodrat habitat preferences in order to guide management. Woodrats build stick nests from natural and artificial materials, so nest distribution and nest occupancy were used as indicators of preference. Distribution was determined by nest surveys, and remote cameras were used to assess occupancy. Forest structure, human disturbance, nest, and animal presence metrics were also collected. More nests were found along abandoned roads than along forest transects and more artificial nests were occupied than natural nests. These findings indicate that woodrats prefer areas with human disturbance, rather than forest age and structure as previously believed. This may have consequences on woodrat management, as it suggests that man-made materials are currently needed by woodrats even in a protected natural area.
280

Nest site fidelity and nest site selection of loggerhead, Caretta Caretta, and leatherback, dermochelys coriacea, turtles in KwaZulu-Natal, South Africa

Botha, Marié January 2010 (has links)
Loggerhead and leatherback sea turtles nest on the beaches of the north-eastern portion of Kwazulu-Natal within the iSimangaliso Wetland Park. Loggerheads place ~60 percent of all nests within an 8 km stretch of beach, whereas leatherbacks tend to space their nests more evenly along the entire length of the monitoring area. The study aimed to determine nest site fidelity of loggerheads and leatherbacks (using four decades of nesting data housed by Ezemvelo KZN Wildlife) and the factors that influence nest site selection of both species within the 56 km of turtle monitoring area (32N to 100S) and the 5 km area of high-density loggerhead nesting (0N to 12N). The effectiveness of nest site selection was then determined through the hatching success of loggerheads over the 5km area (0N to 12N). Results showed that loggerheads show a high degree of nest site fidelity (~3 km) with nest site fidelity of individuals increasing over subsequent seasons of nesting, as well as these individuals using the same stretches of beach for nesting (the most popular area being 1N to 4N for repeat nesters). Leatherbacks displayed nest site fidelity of ~9 km and this did not increase over successive seasons of nesting. In terms of nest site selection, loggerheads and leatherbacks both avoided areas where low shore rock was present, whereas both species preferred nesting on beaches of intermediate morphodynamic state. Leatherback nesting was significantly higher in areas with wider surf zones. Both species were able to surpass the high water mark when nesting as nests below this point would be almost certainly doomed. Hatching success of loggerheads was comparative to high (83 %) relative to other studies, however, nest success varied across the beach from beacon 1N to 12N. Areas where highest nest success was observed were not areas of highest nest density presumably due to artificial lighting. Results from this study increase our understanding of the evolutionary biology of loggerhead and leatherback turtles in South Africa and the effectiveness of loggerhead nest site selection through hatching success.

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