Made available in DSpace on 2014-12-17T14:07:06Z (GMT). No. of bitstreams: 1 RoseaneAB_TESE.pdf: 2502276 bytes, checksum: 8d0bea579c9b9da8a192feccb392ae6a (MD5) Previous issue date: 2011-04-29 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this study it was used two metallic oxides, Ta2O5 and TiO2, in order to obtain metallic powders of Ta and Ti through aluminothermic reduction ignited by plasma. Ta2O5 and TiO2 powders were mixed with Al in a planetary mill, using different milling times. A thermal analysis study (DTA and TG) was carried out, in order to know the temperature to react both the mixtures. Then, these mixtures were submitted to a hollow cathode discharge, where they were reacted using aluminothermic reduction ignited by plasma. The product obtained was characterized by XRD and SEM, where it was proven the possibility of producing these metallic particles, different from the conventional process, where metallic ingots are obtained. It was verified that the aluminothermic reduction ignited by plasma is able to produce metallic powders of Ta and Ti, and a higher efficiency was observed to the process with Ta2O5-Al mixtures. Among different microstructural aspects observed, it can be noted the presence of metallic nanoparticles trapped into an Al2O3 matrix, besides acicular structures (titanium) and dendritic structures (tantalum), which are a product characteristic from a fast cooling / No presente estudo foram utilizados dois ?xidos met?licos, Ta2O5 e TiO2, visando a obten??o de part?culas de Ta e Ti met?licos, por meio da redu??o aluminot?rmica com igni??o a plasma. P?s de Ta2O5 e TiO2 foram misturados com p? de Al e mo?dos em um moinho planet?rio por diferentes per?odos. Um estudo de an?lise t?rmica (DTA e TG) foi realizado, visando se conhecer a temperatura de rea??o para ambas as misturas. Conhecidas essas temperaturas, as misturas foram submetidas a uma descarga em c?todo oco, onde foram reagidas pelo processo de redu??o aluminot?rmica com igni??o a plasma. O material obtido foi caracterizado por DRX e MEV, onde se comprovou a possibilidade da obten??o de um produto na forma de p?, algumas vezes de dimens?es nanom?tricas, diferentemente do processo convencional, onde o produto final ? obtido na forma de lingote. Verificou-se que a redu??o aluminot?rmica com igni??o a plasma ? capaz de produzir p?s de Ta e Ti met?licos, com uma efici?ncia maior para a rea??o da mistura Ta2O5-Al. Dentre os diferentes aspectos microestruturais observados, destaca-se a presen?a de nanopart?culas do metal de interesse embebidas em uma matriz de Al2O3, al?m de estruturas acicular (tit?nio) e dendr?tica (t?ntalo), que s?o caracter?sticas de um resfriamento r?pido

Made available in DSpace on 2014-12-17T14:13:53Z (GMT). No. of bitstreams: 1 MarcoAMS_TESE.pdf: 4598195 bytes, checksum: 64f542a86c9a48f91e63fe82fc791428 (MD5) Previous issue date: 2013-10-08 / Recent years have seen a significant growth in surface modifications in titanium implants, resulting in shorter healing times in regions with low bone density. Among the different techniques, subtraction by chemical agents to increase oxidation has been applied for surface treatment of dental implants. However, this technique is generally unable to remove undesirable oxides, formed spontaneously during machining of titanium parts, raising costs due to additional decontamination stages. In order to solve this problem, the present study used plasma as an energy source to both remove these oxides and oxidize the titanium surface. In this respect, Ti disks were treated by hollow cathode discharge, using a variable DC power supply and vacuum system. Samples were previously submitted to a cleaning process using an atmosphere of Ar, H2 and a mixture of both, for 20 and 60 min. The most efficient cleaning condition was used for oxidation in a mixture of argon (60%) and oxygen (40%) until reaching a pressure of 2.2 mbar for 60 min at 500?C. Surfaces were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), adhesion and cell proliferation. SEM showed less cell spreading and a larger number of projections orfilopodia in the treated samples compared to the control sample. AFM revealed surface defects in the treated samples, with varied geometry between peaks and valleys. Biological assays showed no significant difference in cell adhesion between treated surfaces and the control. With respect to cell proliferation, the treated surface exhibited improved performance when compared to the control sample. We concluded that the process was efficient in removing primary oxides as well as in oxidizing titanium surfaces / Nos ?ltimos anos, tem-se observado um crescimento nas modifica??es superficiais em implantes de tit?nio, que abrevia o tempo de cicatriza??o em regi?es com baixa densidade ?ssea. Dentre as diferentes t?cnicas, a de subtra??o por agentes qu?micos para aumentar a oxida??o vem sendo aplicada para tratamentos superficiais de implantes dentais. Por?m esta t?cnica geralmente n?o propicia a remo??o dos ?xidos indesej?veis formados espontaneamente durante a usinagem de pe?as de tit?nio, aumentando assim o custo, por exigir etapas adicionais para a descontamina??o. Com o objetivo de solucionar esse problema, utilizou-se neste trabalho o plasma como fonte energ?tica, tanto na remo??o desses ?xidos quanto como na oxida??o de superf?cie de tit?nio. Neste sentido, discos de Ti foram tratados em descarga por c?todo oco, usando-se uma fonte de tens?o DC vari?vel e sistema de v?cuo. Previamente, as amostras foram submetidas a processo de limpeza, utilizando-se atmosfera de Ar, H2 e mistura, em tempos de 20 e 60 min. A condi??o de limpeza mais eficaz foi utilizada para a oxida??o, numa mistura de arg?nio (60%) e oxig?nio (40%), at? atingir a press?o de 2,2 mbar durante 60 min, a 500?C. As superf?cies foram caracterizadas por microscopia eletr?nica de varredura (MEV), difra??o de raios X (DRX), microscopia por for?a at?mica (AFM), ades?o e prolifera??o celular. Na microscopia eletr?nica de varredura (MEV), observou-se um menor espraiamento celular e uma maior quantidade de proje??es ou filop?dios nas amostras tratadas, em compara??o ? amostra-controle. A microscopia de for?a at?mica (AFM) mostrou, nas amostras tratadas, defeitos nas superf?cies com geometria variada para picos e vales. Nos ensaios biol?gicos, houve diferen?as significativas na ades?o e prolifera??o celular, em que a superf?cie tratada apresentou um maior desempenho quando comparada com a amostra-controle.Concluiu-se que o processo foi eficiente tanto na remo??o dos ?xidos prim?rios quanto na oxida??o da superf?cie do tit?nio

Made available in DSpace on 2014-12-17T14:16:22Z (GMT). No. of bitstreams: 1 LucianaRS_Pre_textuais.pdf: 37160 bytes, checksum: 5c10ca3517f836e974edc672ecd286cb (MD5) Previous issue date: 2008-02-12 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The inorganic actives, represented mainly by microfine zinc oxide and titanium dioxide, have shown great potential to protect against large UV spectrum. The aim of this study is the development, characterization and analysis of stability in the short term of microemulsions containing inorganic fotoprotection agents. The microemulsions identified by the phases diagram containing the metallic oxides were produced by two different methods and subjected to the centrifugation test and thermal stress cycles, and subsequently characterized by macroscopic evaluation, test dilution, electrical conductivity, pH, particle size, and zeta potential. This study highlights the influence of the metal oxides addition in the structure and distribution of micelles in the microemulsions / Os agentes fotoprotetores inorg?nicos, representados principalmente pelo ?xido de zinco e di?xido de tit?nio microfinos, t?m mostrado grande potencial de prote??o contra amplo espectro de radia??o UV. O objetivo deste trabalho consiste no desenvolvimento, caracteriza??o e estudo de estabilidade a curto termo de microemuls?es contendo agentes fotoprotetores inorg?nicos. As microemuls?es identificadas pelo diagrama de fases e adicionadas dos ativos fotoprotetores foram elaboradas a partir de dois m?todos diferentes e submetidas ao teste de centrifuga??o e ciclos gelo-degelo, sendo posteriormente caracterizadas pela avalia??o macrosc?pica, teste de dilui??o, condutividade el?trica, pH, granulometria e determina??o de potencial zeta. Este estudo evidencia a influ?ncia da adi??o dos ?xidos met?licos na estrutura??o micelar e distribui??o de tamanho de part?culas das microemuls?es

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-12-02T19:49:15Z No. of bitstreams: 1 DaniloCavalcanteBraz_TESE.pdf: 28469447 bytes, checksum: 99cbc13da13290f58060715e274f57b9 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2015-12-09T00:10:10Z (GMT) No. of bitstreams: 1 DaniloCavalcanteBraz_TESE.pdf: 28469447 bytes, checksum: 99cbc13da13290f58060715e274f57b9 (MD5) / Made available in DSpace on 2015-12-09T00:10:10Z (GMT). No. of bitstreams: 1 DaniloCavalcanteBraz_TESE.pdf: 28469447 bytes, checksum: 99cbc13da13290f58060715e274f57b9 (MD5) Previous issue date: 2014-06-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / A utiliza??o de materiais biom?dicos tendo como constituinte os nitretos, ?xidos e oxinitretos de tit?nio vem crescendo devido ?s propriedades biocompat?veis. Sendo assim, superf?cies de tit?nio foram tratadas termoquimicamente em atmosferas de plasma contendo misturas de Ar+N2+O2 e estudada a influ?ncia das diferentes superf?cies sobre a resposta da ades?o e agrega??o plaquet?ria. Foi verificado por an?lises de difra??o de raios-X com incid?ncia rasante (GIXRD) e espectroscopia micro Raman a presen?a de nitretos, oxinitretos e ?xidos de tit?nio, obtendo assim, diferentes propriedades em cada superf?cie. No caso da rugosidade, as amostras tratadas somente com arg?nio e nitrog?nio, foram as que obtiveram maior valor, sendo que o processo de sputtering ocasionado por esses dois gases ocasionou menores valores nos ensaios de nanodureza. Na an?lise de ?ngulo de contato com a ?gua, apesar de todas apresentarem car?ter hidrof?lico, houve uma diminui??o no valor do ?ngulo para amostras tratadas com adi??o de apenas com nitrog?nio ou oxig?nio, em compara??o com aquelas oxinitretadas. O ensaio de ?ngulo de contato tamb?m foi realizado com o plasma sangu?neo e foi obtida uma tend?ncia ao mesmo comportamento com a ?gua, ou seja, maiores valores para as superf?cies oxinitretadas. Com respeito aos ensaios de ades?o e agrega??o plaquet?ria verificou-se que as atmosferas contendo menor concentra??o de arg?nio (menor dilui??o) a distancia m?dia entre as plaquetas foi menor para amostras nitretadas e oxidadas quando comparadas com as amostras oxinitretadas. Para o grupo com maior concentra??o de arg?nio, al?m de apresentarem menores distancias m?dias entre as plaquetas, verificou-se maior tamanho de agregrado plaquet?rio, indicando o inicio da forma??o de trombos na superf?cie do material. A morfologia das plaquetas tamb?m informa o inicio do processo de agrega??o, e para as amostra nitretadas, as plaquetas apresentaram forma??o de psed?podes indicando a uma maior ader?ncia a superf?cie.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-17T21:48:49Z No. of bitstreams: 1 NataliaDeFreitasDaudt_TESE.pdf: 11328330 bytes, checksum: dbd5828f503f9e2ae820e46b2ab41fab (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-02-17T23:30:27Z (GMT) No. of bitstreams: 1 NataliaDeFreitasDaudt_TESE.pdf: 11328330 bytes, checksum: dbd5828f503f9e2ae820e46b2ab41fab (MD5) / Made available in DSpace on 2016-02-17T23:30:27Z (GMT). No. of bitstreams: 1 NataliaDeFreitasDaudt_TESE.pdf: 11328330 bytes, checksum: dbd5828f503f9e2ae820e46b2ab41fab (MD5) Previous issue date: 2015-03-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / No presente estudo, amostras de tit?nio altamente porosas foram produzidas atrav?s de Moldagem por Inje??o de p?s Met?licos (Metal Injection Moulding - MIM) com adi??o de agente espa?ante (space holder). MIM permite a produ??o de amostras com geometrias complexas, alto grau de automatiza??o e custos reduzidos em larga escala de produ??o. A adi??o de part?culas de agente espa?ante ? MIM possibilita a produ??o de amostras com porosidade funcional, fazendo com que esse m?todo seja especialmente atrativo para a produ??o de implantes biom?dicos. Entretanto, a aplica??o desta t?cnica tem sido limitada pelo fato de que a porosidade na superf?cie das amostras ? parcialmente fechada e as condi??es de processamento n?o s?o est?veis quando a quantidade de agente espa?ante excede 55 Vol.%. Deforma??o e at? o colapso das amostras foram observados quando amostras contentando mais 55 Vol.% de retentor espacial foram sinterizadas. Contudo, para implantes de tit?nio, produzidos pelo m?todo do agente espa?ante, uma porosidade final no intervalo de 60-65 Vol.% e uma porosidade aberta na superf?cie s?o necess?rias para atingir uma porosidade interligada que permita o crescimento ?sseo. Portanto, neste estudo, tr?s abordagens foram conduzidas visando a produ??o de amostras de tit?nio altamente porosas com uma porosidade aberta na superf?cie atrav?s da MIM com adi??o de KCl como agente espa?ante. Primeiro, a quantidade de s?lidos (agente espa?ante e tit?nio) no material de trabalho foi otimizada. A quantidade de s?lidos foi aumentada at? 80 Vol.%. Evitar o bloqueio da injetora durante a inje??o do material de trabalho foi o principal desafio, consequentemente um grande esfor?o foi empregado para melhorar a homogeneiza??o do material de trabalho e a otimiza??o dos par?metros de processo e, assim, permitir a inje??o dos materiais de trabalho com at? 80 Vol.% de s?lidos. O aumento na quantidade de s?lidos melhorou a estabilidade geom?trica das amostras injetadas durante a extra??o t?rmica do ligante e a sinteriza??o, permitindo a sinteriza??o de amostras contendo 70 Vol.% de agente espa?ante sem deforma??o. Depois, remo??o agente espa?ante foi realizada atrav?s de sublima??o do KCl durante a sinteriza??o a v?cuo, o que permitiu omitir a etapa mais lenta do processo: a dessaliniza??o em solvente, e aumentar ainda mais a estabilidade geom?trica das amostras. E por ?ltimo, tratamento por plasma foi introduzido nas amostras antes da etapa final de sinteriza??o. Primeiramente, o tratamento por plasma foi aplicado ?s amostras porosas obtidas por compacta??o a quente do material de trabalho com 70 Vol.% de agente espa?ante. Os resultados obtidos para amostras compactadas foram transferidos para produ??o e tratamento por plasma das Abstract ________________________________________________________________________________ amostras injetadas. Uma investiga??o detalhada foi conduzida com o objetivo de determinar o mecanismo de modifica??o por plasma das amostras injetadas com agente espa?ante. Al?m disso, ligas de a?o bem conhecidas foram tratadas por plasma a fim de avaliar a temperatura durante o tratamento das amostras injetadas. As amostras porosas de tit?nio foram analisadas com rela??o ao efeito do tratamento por plasma e da composi??o do material de trabalho na contamina??o por elementos intersticiais, precis?o geom?trica ap?s cada etapa do processamento, microestrutura, porosidade no volume e na superf?cie da amostra. O tratamento por plasma aumentou a quantidade de poros abertos na superf?cie e melhorou a precis?o geom?trica das amostras. Logo, tratamento por plasma de amostras produzidas por MIM com adi??o de agente espa?ante tem potencial para ser aplicado como processo padr?o de produ??o de amostras altamente porosas. Resumindo, todas as rotas estudadas s?o promissoras para a produ??o de implantes de tit?nio porosos atrav?s da MIM, uma vez que permitem a sinteriza??o de tit?nio altamente poroso com boa precis?o geom?trica, porosidade aberta na superf?cie e porosidade final no intervalo adequado para o crescimento ?sseo (cerca de 65 Vol.%). / A combina??o da Moldagem por Inje??o de p?s Met?licos (Metal Injection Moulding MIM) e o M?todo do Retentor Espacial (Space Holder Method - SHM) ? uma t?cnica promissora para fabrica??o de pe?as porosas de tit?nio com porosidade bem definida como implantes biom?dicos, uma vez que permite um alto grau de automatiza??o e redu??o dos custos de produ??o em larga escala quando comparado a t?cnica tradicional (SHM e usinagem a verde). Contudo a aplica??o desta t?cnica ? limitada pelo fato que h? o fechamento parcial da porosidade na superf?cie das amostras, levando ao deterioramento da fixa??o do implante ao osso. E al?m disso, at? o presente momento n?o foi poss?vel atingir condi??es de processamento est?veis quando a quantidade de retentor espacial excede 50 vol. %. Entretanto, a literatura descreve que a melhor faixa de porosidade para implantes de tit?nio para coluna vertebral est? entre 60 - 65 vol. %. Portanto, no presente estudo, duas abordagens foram conduzidas visando a produ??o de amostras altamente porosas atrav?s da combina??o de MIM e SHM com o valor constante de retentor espacial de 70 vol. % e uma porosidade aberta na superf?cie. Na primeira abordagem, a quantidade ?tima de retentor espacial foi investigada, para tal foram melhorados a homogeneiza??o do feedstock e os par?metros de processo com o prop?sito de permitir a inje??o do feedstock. Na segunda abordagem, tratamento por plasma foi aplicado nas amostras antes da etapa final de sinteriza??o. Ambas rotas resultaram na melhoria da estabilidade dimensional das amostras durante a extra??o t?rmica do ligante e sinteriza??o, permitindo a sinteriza??o de amostras de tit?nio altamente porosas sem deforma??o da estrutura.

Made available in DSpace on 2014-12-17T14:58:13Z (GMT). No. of bitstreams: 1 RaquelGC_DISSERT.pdf: 1617455 bytes, checksum: fe137c67d61e0483bac922261c815e1e (MD5) Previous issue date: 2011-11-23 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / In this study we used the plasma as a source of energy in the process of carbothermic reduction of rutile ore (TiO2). The rutile and graphite powders were milled for 15 h and placed in a hollow cathode discharge produced by in order to obtain titanium carbonitride directly from the reaction, was verified the influence of processing parameters of plasma temperature and time in the synthesis of TiCN. The reaction was carried out at 600, 700 and 800˚C for 3 to 4 hours in an atmosphere of nitrogen and argon. During all reactions was monitored by plasma technique of optical emission spectroscopy (EEO) to check the active species present in the process of carbothermal reduction of TiO2. The powder obtained after the reactions were characterized by the techniques of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The technique of EEO were detected in all reactions the spectra CO and NO, and these gas-phase resulting from the reduction of TiO2. The results of X-ray diffraction confirmed the reduction, where for all conditions studied there was evidence of early reduction of TiO2 through the emergence of intermediate oxides. In the samples reduced at 600 and 700˚C, there was only the phase Ti6O11, those reduced to 800˚C appeared Ti5O9 phases, and Ti6O11 Ti7O13, confirming that the carbothermal reduction in plasma, a reduction of the ore rutile (TiO2) in a series of intermediate titanium oxide (TinO2n-1) where n varies between 5 and 10 / Neste trabalho foi utilizado o plasma como fonte energ?tica no processo de redu??o carbot?rmica do min?rio rutilo (TiO2). Os p?s de rutilo e grafite foram mo?dos durante 15 h e introduzidos numa descarga produzida por c?todo oco a fim de obter carbonitreto de tit?nio diretamente da rea??o, sendo verificado a influ?ncia dos par?metros de processamento de plasma, temperatura e tempo na s?ntese de TiCN. As rea??o foram efetuadas a 600, 700 e 800˚C por 3 e 4 horas numa atmosfera de nitrog?nio e arg?nio. Durante todas as rea??es o plasma foi monitorado pela t?cnica de espectroscopia de emiss?o ?ptica (EEO) para verificar as esp?cies ativas presente no processo de redu??o carbot?rmica de TiO2. Os p?s obtidos ap?s as rea??es foram caracterizados pelas t?cnicas de difra??o de raios X (DRX) e microscopia eletr?nica de varredura (MEV). Pela t?cnica de EEO foram detectados em todas as rea??es os espectros CO e NO, sendo essas fases gasosas resultante da redu??o do TiO2. Os resultados de difra??o de raios X confirmou essa redu??o, onde para todas as condi??es estudadas houve evid?ncia de in?cio da redu??o do TiO2 atrav?s do aparecimento de ?xidos intermedi?rios. Nas amostras reduzidas a 600 e 700˚C observou-se apenas a fase Ti6O11, naquelas reduzidas a 800 ˚C apareceram as fases Ti5O9, Ti6O11 e Ti7O13, comprovando que com a redu??o carbot?rmica em plasma, houve redu??o do min?rio rutilo (TiO2) em uma s?rie de ?xido intermedi?rios de tit?nio (TinO2n-1) onde n varia entre 5 e 10

Personality and individual differences in reactions of the Great tit to aposematic prey were investigated. The aim of this study was to assess differences in personality of forty Great tits and find out possible correlation to the reactions of these birds to aposematic prey, the fifth larval instar of firebug Pyrrhocoris apterus.

Avian malaria (Plasmodium spp.) is a popular model system to study the ecology and evolution of parasite-host-vector interactions in the wild. These studies have historically focused mostly on the avian hosts and the malaria parasites. Knowledge regarding the role of vectors is essential to our understanding of these wild systems, but has only very recently started to accumulate. This thesis aimed to contribute to this field by assessing mosquito-malaria-host associations for British mosquitoes and the role of mosquito ecology in shaping these parasite systems in a British woodland study site, using molecular, field ecology and statistical modelling methodologies. From the 12 mosquito species or species groups found, I showed that the Cx.pipiens/torrentium mosquito group is likely to have a major role in avian malaria transmission in Great Britain, while Cs. annulata may be transmitting P. circumflexum. I also demonstrated a positive spatial association between mosquito density per host and avian malaria prevalence, in accordance with theoretical expectations for malaria transmission. Findings here provide evidence that avian malaria transmission in British woodlands is limited mainly to June-August, being preceded by relapse of previous infections or, alternatively, by maintenance of chronic blood parasitaemia through the colder months; this agrees with theoretical expectations and findings elsewhere for temperate climates. This thesis also described local-scale spatial heterogeneity and seasonal variation in adult mosquito abundance within a British woodland where avian malaria is endemic, with differing patterns found between species or species groups. Spatially, variation in adult mosquito abundance was associated with microclimatic and landscape variables such as distances to mosquito breeding sites, microclimate and canopy height; seasonally, variation in mosquito abundance was associated with temperature and rainfall, alongside calendar date. The heterogeneity in mosquito parameters and associations with environmental variables found at a site where avian malaria is endemic highlights the need to anticipate such complexity when trying to understand Plasmodium transmission. By doing so, we further extend the potential of these parasite systems to improve our knowledge regarding the ecology and evolution of parasite-host-vector associations.

Au niveau interpersonnel, la psychopathie implique un manque de considération d’autrui pouvant se manifester par la tromperie, la manipulation et l’exploitation. La présente thèse a investigué la relation entre les caractéristiques psychopathiques d'individus non incarcérés et la tendance à coopérer dans un jeu du dilemme du prisonnier itératif. Un total de 85 hommes ont été recrutés via une annonce qui ciblait des traits de personnalité correspondant à des caractéristiques psychopathiques exprimées de façon non péjorative. Plusieurs méthodes ont été employées pour rejoindre les participants : 46 ont participés en personne après avoir répondu à une invitation affichée dans un journal local ainsi que sur des babillards à proximité d'une université; 39 ont complété l'étude sur Internet après avoir été recrutés via un site web de petites annonces. Chaque participant a répondu à un questionnaire incluant l’Échelle Auto-rapportée de Psychopathie (Levenson, Kiehl, & Fitzpatrick, 1995) et l’Échelle Auto-rapportée des Indicateurs de Psychopathie de l’Enfance et de l’Adolescence (Seto, Khattar, Lalumière, & Quinsey, 1997). Ils ont également complété une simulation informatique du dilemme du prisonnier itératif comprenant 90 essais. La simulation informatique utilisée pour évaluer les participants en personne ainsi que la version accessible par Internet ont été conçues et programmées spécifiquement pour la présente thèse. La simulation informatique incluait trois stratégies souvent associées au dilemme du prisonnier itératif : donnant-donnant, donnant-donnant-généreux et gagne/reste-perd/change. Les analyses préliminaires ont montré que les participants vus en personne et ceux rejoints par Internet ne différaient pas en termes de variables sociodémographiques, des caractéristiques psychopathiques, de la désirabilité sociale et des réponses au dilemme du prisonnier. Une régression multiple standard a indiqué que les mesures psychopathiques ne pouvaient pas prédire le nombre total de choix coopératifs dans le jeu. Par contre, une corrélation négative a été trouvée entre les caractéristiques interpersonnelles et affectives de la psychopathie et la coopération dans le premier tiers du jeu. De plus, les participants qui présentaient davantage de caractéristiques psychopathiques interpersonnelles et affectives avaient plus souvent réussi à exploiter l'ordinateur en dénonçant alors que la simulation informatique coopérait. Des analyses multi-niveaux ont exploré la contribution de variables au niveau de la décision et au niveau de l'individu dans la prédiction du choix de coopérer ou de dénoncer lors de chaque essai du jeu; les interactions entre ces variables ont aussi été considérées. Les résultats ont montré que les variables au niveau de la décision influençaient généralement plus fortement les chances de coopérer que les variables au niveau de l'individu. Parmi les mesures de la psychopathie, seulement les caractéristiques interpersonnelles et affectives ont montré une association significative avec les chances de coopérer; les interactions avec le premier choix effectué dans le jeu et le premier tiers du jeu étaient significatives. Ainsi, si un participant avait coopéré au premier essai, la présence de caractéristiques psychopathiques interpersonnelles et affectives était associée à une diminution de ses chances de coopérer par la suite. Aussi, durant les 30 premiers essais du jeu, la présence de caractéristiques psychopathiques interpersonnelles et affectives était associée à une diminution des chances de coopérer. La stratégie adoptée par la simulation informatique n'avait pas d'influence sur le lien entre les caractéristiques psychopathiques et la probabilité de coopérer. Toutefois, le fait de jouer contre donnant-donnant était associé à de plus fortes chances de coopérer d'un essai à l'autre pour l'ensemble des participants. Globalement, les résultats suggèrent que les hommes non incarcérés présentant des caractéristiques psychopathiques ne seraient pas nécessairement portés à choisir systématiquement la non-coopération. En fait, les caractéristiques interpersonnelles et affectives de la psychopathie ont semblé se traduire par une tendance à faire bonne impression au départ, tenter rapidement d'exploiter autrui en dénonçant, puis finir par coopérer. Cette tendance comportementale est discutée, ainsi que la pertinence d'utiliser le dilemme du prisonnier itératif et les analyses multi-niveaux pour étudier le comportement interpersonnel des psychopathes. / Interpersonally, psychopathy involves a lack of consideration for others that can translate into deception, manipulation, and exploitation. The current thesis investigated the relationship between the psychopathic characteristics of non incarcerated men and the tendency to cooperate while playing an iterative version of the prisoner's dilemma game. A total of 85 men were recruited through advertisements that targeted personality traits corresponding to psychopathic characteristics formulated in a way that was not pejorative. A variety of methods was used to reach participants; 46 were tested in person after they replied to an invitation that appeared in a local journal as well as on bulletin boards close to a university; 39 participated via the Internet after they were recruited through a classified advertising website. Each participant completed a questionnaire including the Levenson Self-Report Psychopathy Scale (Levenson, Kiehl, & Fitzpatrick, 1995) and the Childhood and Adolescent Taxon Scale - Self-Report (Seto, Khattar, Lalumière, & Quinsey, 1997). They also played in a computer simulation of the iterative prisoner's dilemma lasting 90 trials. Both the computer simulation used to test participants in person and the Internet version were designed and programmed specifically for the present thesis. The computer simulation included three strategies often associated with the iterative prisoner's dilemma: tit-for-tat, generous-tit-for-tat, and win/stay-lose/shift. Preliminary analyses showed that participants tested in person and via the Internet did not differ in terms of sociodemographic variables, psychopathic characteristics, social desirability, or responses to the prisoner's dilemma. A standard multiple regression indicated that psychopathic measures could not predict the total number of cooperative choices in the prisoner's dilemma game. However, there was a negative correlation between interpersonal and affective characteristics of psychopathy and cooperation in the first third of the prisoner's dilemma game. Furthermore, participants showing more interpersonal and affective psychopathic characteristics tended to exploit the computer more often by defecting while the computer simulation cooperated. Multilevel analyses were used to explore the contribution of decision-level and individual-level variables to predict the choice to cooperate or to defect on each trial of the game; interactions between these variables were also considered. The results showed that variables at the decision level were generally associated with stronger odds of cooperating than individual-level variables. Among psychopathic measures, only the interpersonal and affective characteristics showed a significant association with the odds of cooperating; interactions with the first choice in the game and the first third of the game were significant. That is, if participants cooperated in the first trial, higher interpersonal and affective psychopathic characteristics were associated with decreased odds of cooperating. Also, during the first 30 trials of the game, participants with higher interpersonal and affective psychopathic characteristics were significantly more likely to defect. The type of strategy used by the computer simulation did not have an influence on the relationship between psychopathic characteristics and a participant's probability to cooperate. However, playing against tit-for-tat was associated with increased odds of cooperating from one trial to the next for all participants. Overall, the results suggest that non incarcerated men with psychopathic characteristics might not systematically choose to defect. Instead, the interpersonal and affective psychopathic characteristics appeared as a tendency to cooperate initially, then rapidly attempt to exploit by defecting, and finally cooperate. This behavioral pattern is discussed as well as the relevance of using the iterative prisoner's dilemma game and multilevel analyses to study interpersonal behavior in psychopaths.

Inbreeding occurs when relatives mate and have offspring. Inbreeding depression is hypothesized to have influenced the evolution of mating systems and behavioural mechanisms of inbreeding avoidance in the animal kingdom. Inbreeding in the wild is difficult to measure, as in order to build a pedigree allowing us to identify matings between relatives, the identity of as many as possible members of a population needs to be known. For a long time, the main source of knowledge about inbreeding depression was based on laboratory and agricultural studies, which did not reflect the array of environmental pressures wild populations have to cope with. In consequence, the deleterious consequences of inbreeding have often been underestimated. This is problematic because accurate estimates of the effect size of inbreeding depression are needed to study the strength of selection on inbreeding avoidance mechanisms, and are also of importance to conservation genetics. The aim of this thesis was to use pedigree data to infer the occurrence and effects of inbreeding using over forty years of breeding events of the great tit Parus major from Wytham Woods, Oxfordshire. The effects of inbreeding on fitness were investigated across a life-history continuum, and across environments. I found that close inbreeding (f=0.25) resulted in pronounced inbreeding depression, which acted independently on hatching success, fledging success, and recruitment success, and reduced the number of fledged grand-offspring by 55%. My results therefore suggest that estimates of fitness costs of inbreeding must focus on the entire life cycle. I also show that the variation in the strength of inbreeding depression varies across environments, particularly so the more the environmental variable considered is linked to fitness. These results emphasise the need of using relevant environmental contrasts when investigating inbreeding by environment interactions. I further asked whether individuals involved in matings with relatives differed relative to individuals mating with unrelated partners. I did not find any evidence for clear predictors of inbreeding, and I show that inbreeding depression in our population is entirely independent of any tendency for low quality parental genotypes, or phenotypes, to inbreed. Neither did I find any evidence for active inbreeding avoidance: great tits did not mate less often with kin than expected based on several scenarios of random mating, nor did I find increased rates of extra-pair paternity among birds breeding with relatives. In fact, I observed quite the contrary, as birds mating with kin exhibited a higher than average rate of close inbreeding relative to all scenarios of random mating investigated, showed lower rates of extra-pair paternity and divorce than birds mated to unrelated partners. I hypothesise that cases of occasional inbreeding in this population may result from mis-imprinting or a related process whereby some birds develop particularly strong bonds that are at odds with all predictions of avoiding inbreeding. Finally, I asked to what extent natal dispersal, a behaviour that is often hypothesized to play an important role in avoiding inbreeding, indeed reduces the likelihood of inbreeding. I found that male and female individuals breeding with a relative dispersed over several-fold shorter distances than those outbreeding. This led to a 3.4 fold increase (2.3-5, 95% CI) in the likelihood of close inbreeding relative to the population average when individuals dispersed less than 200m. This thesis demonstrates that inbreeding has deleterious effects on a wild population of birds, occurring throughout an individual’s life, and is of varying strength across environments. My findings strongly support the theory that natal dispersal should be considered as a mechanism of prime importance for inbreeding avoidance.