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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.
131

Interactions précoces mère-enfant en situation de négligence émotionnelle sévère : étude transdisciplinaire de la synchronie et de la mentalisation réflexive maternelle / Early mother-child early interactions in the context of severe emotional neglect : transdisciplinary approach of synchrony and maternal insighfulness

Leclère, Chloë 24 November 2015 (has links)
L'étude des interactions précoces est complexe mais essentielle à la compréhension de la psychopathologie de la petite enfance. La négligence émotionnelle est une forme courante mais discrète de maltraitance. Elle correspond à une défaillance chronique de la part du parent à offrir à l'enfant, au sein de leur relation, un environnement affectif suffisamment bon pour son développement. Notre recherche explore les interactions précoces mère-enfant de ces situations de négligence émotionnelle par une approche transdisciplinaire à travers deux dimensions : la synchronie et la mentalisation réflexive maternelle. La synchronie est une caractéristique dyadique et temporelle de l'interaction qui traduit la fluidité et la qualité d'un échange par une adaptation dynamique et réciproque des comportements et états émotionnels des partenaires interactifs. Elle constitue un signal social en soi, facteur de qualité de l'interaction. La mentalisation réflexive, traduction du terme Insightfulness (Oppenheim, 2001), évoque la capacité du parent à prendre le point de vue de l'enfant et à comprendre, de façon empathique, les motivations sous-jacentes à ses comportements. Les objectifs de cette recherche sont (1) d'analyser la dynamique comportementale des interactions précoces en élaborant une méthodologie d'analyse computationnelle et (2) d'évaluer l'influence des capacités maternelles de mentalisation réflexive et notamment de leur dynamique intrapsychique, sur la dynamique interactive, dans les situations de négligence émotionnelle. Des mères et leur enfant de 13 à 38 mois, appartenant au groupe en situation de négligence émotionnelle (N=10) et au groupe contrôle sans trouble des interactions (N=9), sont filmés au cours d'un jeu interactif libre. Les vidéos font l'objet d'une double évaluation clinique et computationnelle. La première permet d'obtenir une évaluation clinique globale de la qualité de l'interaction par le Coding Interactive Behavior (Feldman et Keren 1998; Viaux 2014). La seconde, par les techniques de traitement du signal social, offre l'accès à une micro-analyse computationnelle des mouvements des partenaires et de leurs échanges dyadiques. Dans un second temps, 14 mères (n=7 mères en situation de négligence et n=7 mères sans trouble des interactions) ont visionné des extraits de la vidéo de leurs interactions, au cours d'un entretien semi-structuré, l'Insightfulness Assessment (Oppenheim et Koren-Karie, 2001) afin d'évaluer leurs capacités de mentalisation réflexive. Une analyse additionnelle des verbatim a permis d'accéder à des éléments de la dynamique intrapsychique. Les résultats mettent en évidence de nombreuses corrélations significatives les dimensions du CIB (notamment la sensibilité, l'intrusivité maternelle et la réciprocité dyadique) et la micro-analyse automatique (à travers l'activité du corps de la mère). Par ailleurs, les situations de négligence émotionnelle présentent des difficultés de mentalisation empathique. Les entretiens sont caractérisés par des représentations appauvries de leur enfant et des difficultés d'élaboration autour des affects et de la relation mère enfant. La dynamique intrapsychique, influencée par les problématiques inconscientes, s'associe en partie à la dynamique interactive comportementale. Il apparaît que la compréhension de la qualité de l'interaction peut passer par une observation sur une échelle de temps réduite de la dynamique interactive. Par ailleurs, un entretien avec support vidéo étaye l'élaboration de la mère et favorise une mise en mouvement intrapsychique, pouvant constituer ainsi un levier thérapeutique. / Studying early interaction is complex but essential for understanding psychopathology during infancy. Emotional Neglect is a common but insidious form of child maltreatment. It refers to parental failure to give children an emotional environment that allows adequate psychological, cognitive and physical development. We explore mother-infant interaction in these situations following a transdisciplinary approach which consider Synchrony and Insightfulness. Synchrony is a dynamic and reciprocal adaptation of the temporal structure of behaviour and shared affect between interactive partners. It is regarded as a social signal per se. Insightfulness involves the parents' ability to see things from the child point of view and to empathically think about and consider the motives underlying their childrens' behaviour. The aims of this research are (A) to report a novel method to assess features of interactive behavioral dynamics and (B) to assess/underline the impact of Insighfulness, in particular its dynamics, on interactive behavioral dynamics in case/situations of severe emotional neglect. Mothers and children aged from 13 to 38 months (10 in situation of severe emotional neglect and 10 controls) are video recorded during free play. Features of social signal extract by our automatic computational method are compared to qualitative interaction assessment by using the Coding Interactive Behaviour in its French version (Feldman et Keren 1998; Viaux 2014). Secondly, 14 mothers (7 in situation of emotional neglect and 7 without interaction problem) are interviewed during a video-feedback session by using the Insightfulness Assessment (Oppenheim, Koren-Karie, 2001) to assess Insightfulness. An additional qualitative verbatim analysis was performed to explore intrapsychic dynamics. Self-administered questionnaires (BITSEA and Care Support) are proposed to mothers. Results show that individual and synchrony motion features perfectly correlates CIB composite scores trough maternal sensitivity, intrusivity and dyadic reciprocity. Furthermore, pathological mothers are mostly categorised as non-Insighful. Interviews are characterized by poor representations and a lack of elaboration. Intrapsychic dynamics is partly associated with interactive behavioral dynamics. We conclude that computational method might be promising for future studies. It opens an observation window to understand early interactions by changing the time scale. Moreover, interview with a video support seems to underpin maternal elaboration and enhance an intrapsychic movement.
132

Contribution différentielle de Neuroligine‐1 et d’EphA4 à la régulation du sommeil

Freyburger, Marlène 08 1900 (has links)
Le sommeil est un besoin vital et le bon fonctionnement de l’organisme dépend de la quantité et de la qualité du sommeil. Le sommeil est régulé par deux processus : un processus circadien qui dépend de l’activité des noyaux suprachiasmatiques de l’hypothalamus et qui régule le moment durant lequel nous allons dormir, et un processus homéostatique qui dépend de l’activité neuronale et se reflète dans l’intensité du sommeil. En effet, le sommeil dépend de l’éveil qui le précède et plus l’éveil dure longtemps, plus le sommeil est profond tel que mesuré par des marqueurs électroencéphalographiques (EEG). Des études ont montré que le bon fonctionnement de ces deux processus régulateurs du sommeil dépend de la plasticité synaptique. Ainsi, les éléments synaptiques régulant la communication et la force synaptique sont d’importants candidats pour agir sur la physiologie de la régulation du sommeil. Les molécules d’adhésion cellulaire sont des acteurs clés dans les mécanismes de plasticité synaptique. Elles régulent l’activité et la maturation des synapses. Des études ont montré que leur absence engendre des conséquences similaires au manque de sommeil. Le but de ce projet de thèse est d’explorer l’effet de l’absence de deux familles de molécule d’adhésion cellulaire, les neuroligines et la famille des récepteur Eph et leur ligand les éphrines dans les processus régulateurs du sommeil. Notre hypothèse est que l’absence d’un des membres de ces deux familles de molécule affecte les mécanismes impliqués dans le processus homéostatique de régulation du sommeil. Afin de répondre à notre hypothèse, nous avons étudié d’une part l’activité EEG chez des souris mutantes n’exprimant pas Neuroligine‐1 (Nlgn1) ou le récepteur EphA4 en condition normale et après une privation de sommeil. D’autre part, nous avons mesuré les changements moléculaires ayant lieu dans ces deux modèles après privation de sommeil. Au niveau de l’activité EEG, nos résultats montrent que l’absence de Nlgn1 augmente la densité des ondes lentes en condition normale et augment l’amplitude et la pente des ondes lentes après privation de sommeil. Nlgn1 est nécessaire au fonctionnement normal de la synchronie corticale, notamment après une privation de sommeil, lui attribuant ainsi un rôle clé dans l’homéostasie du sommeil. Concernant le récepteur EphA4, son absence affecte la durée du sommeil paradoxal ainsi que l’activité sigma qui dépendent du processus circadien. Nos résultats suggèrent donc que ce récepteur est un élément important dans la régulation circadienne du sommeil. Les changements transcriptionnels en réponse à la privation de sommeil des souris n’exprimant pas Nlgn1 et EphA4 ne sont pas différents des souris sauvages. Toutefois, nous avons montré que la privation de sommeil affectait la distribution des marques épigénétiques sur le génome, tels que la méthylation et l’hydroxyméthylation, et que l’expression des molécules régulant ces changements est modifiée chez les souris mutantes pour le récepteur EphA4. Nos observations mettent en évidence que les molécules d’adhésion cellulaire, Nlgn1 et le récepteur EphA4, possèdent un rôle important dans les processus homéostatique et circadien du sommeil et contribuent de manière différente à la régulation du sommeil. / Sleep is a vital need and the proper functioning of the body depends on the amount and quality of sleep. Sleep is regulated by two processes: a circadian process that depends on the activity of suprachiasmatic nuclei of the hypothalamus and regulates the time of day during which we are going to sleep, and a homeostatic process that seems to depend on neuronal activity and that reflects sleep intensity. The homeostatic process controls a pressure for sleep as a function of the amount of time spent awake. Indeed, sleep quality depends on the duration of preceding wakefulness, the more one is awake, deeper the sleep afterwards as measured by electroencephalographic markers (EEG). Studies have shown that the proper functioning of these two sleep regulatory processes depends on synaptic plasticity. Thus, elements that regulate synaptic communication and synaptic strength are important candidates to act upon the physiology of sleep regulation. Cell adhesion molecules are key elements regulating synaptic plasticity. They control synapse activities and maturation. Studies have shown that their absence leads to consequences similar to sleep deprivation. The aim of this study is to explore the effect of the absence of two different cellular adhesion molecule, Neuroligin‐1 and EphA4 receptor in sleep regulatory processes. Our hypothesis is that the absence of either of these molecules will affect sleep regulation and more specifically sleep homeostasis. To address our hypothesis, we first studied EEG activity in mice which do not express Nlgn1 and EphA4 in normal condition or after sleep deprivation. Secondly, we measured the molecular changes that occur in these two models after sleep deprivation. At the level of EEG activity, our results show that the absence of Nlgn1 increases the density of slow waves under baseline condition, and that the amplitude and slope of slow waves are increased after sleep deprivation. We concluded that Nlgn1 is required for normal functioning of cortical synchrony especially after sleep deprivation, thereby giving it a key role in sleep homeostasis. Regarding the EphA4 receptor, its absence affects the duration of paradoxal sleep and sigma activity which are known to depend on the circadian process. These results suggest that the EphA4 receptor is an important element in the circadian regulation of sleep. The transcriptional response after sleep deprivation in mice not expressing Nlgn1 or EphA4 is not different from that in wild‐type mice. However, we found that sleep deprivation affects the distribution of specific epigenetic markers like methylation and hydroxymethylation and the expression of molecules regulating these changes is altered in EphA4 null mice. Our observations show that two cell adhesion molecules, Nlgn1 and EphA4 receptor, have an important role in the homeostatic and circadian sleep process and contribute differentially to sleep regulation.
133

Movement synchrony, social bonding and pro-sociality in ontogeny

Tuncgenc, Bahar January 2016 (has links)
Human sociality, with its wide scope, early ontogeny and pervasiveness across cultures, is remarkable from an evolutionary perspective. We form bonds with other individuals and live in large social groups. We help, empathise with and share our resources with others, who are unfamiliar and genetically unrelated to us. It has been suggested that interpersonal coordination and rhythmic synchronisation of movements may be one proximate mechanism that enables such widespread human sociality and facilitates cooperation. In the last decade, considerable research has examined the effect of movement synchrony on social bonding and cooperation. However, when this thesis started, there was virtually no experimental study investigating the ontogeny of the movement synchrony-social bonding link, which is proposed to have deep evolutionary roots and important, long-lasting consequences in social life. This thesis aims to investigate the effects of movement synchrony on social bonding and cooperative behaviour across different time points in ontogeny. Three experimental studies were conducted examining infancy, early childhood and middle childhood. Each study explored a different aspect of social bonding and cooperation based on the motor, social and cognitive developments that mark that age group. Study 1a found that at 12 months of age, infants prefer individuals who move in synchrony with them, when the individuals are social entities, but not when they are non-social. Study 1b showed no preferences for synchrony at 9 months in either social or non-social contexts, however. Study 2 revealed that in early childhood, performing synchronous movements actively with a peer facilitates helping behaviour among the children, as well as eye contact and mutual smiling during the interaction. Finally, Study 3 showed that the social bonding effects of movement synchrony applied to inter- group settings and that performing synchronous movements with out-groups increased bonding towards the out-group in middle childhood. This thesis followed an interdisciplinary, integrative and naturalistic approach, where (i) literature from a wide range of disciplines motivated and guided the present research; (ii) links between motor, social and cognitive aspects of development, which are often investigated separately, are formed; and (iii) the experiments were designed in ways that represent the real-life occurrences of the investigated phenomena. The current findings provide the first substantial evidence that movement synchrony facilitates social bonding and cooperation in childhood and thereby provides a foundation for future research.
134

La formation agentive en français : les composés [VN/A/Adv/P]<sub>N/A</sub> et les dérivés V-<i>ant</i>, V-<i>eur</i> et V-<i>oir</i>(<i>e</i>)

Rosenberg, Maria January 2008 (has links)
<p>This study addresses the French morphological construction [VN/A/Adv/P]<sub>N/A</sub>. The main objectives are to posit a single rule for its formation and to question the implications of the agent polysemy. The theoretical framework is lexeme-based morphology, which adheres to weak lexicalism.</p><p>The first part of our analysis is qualitative and concerns the availability aspect of productivity. The method is introspective. The internal semantic patterns of the French construction are examined. Our results give evidence for the claim that a single morphological construction rule, [VN/A/Adv/P]<sub>N/A</sub>, is responsible for the cases where the first constituent is a verb stem, and the second constituent may correspond to an internal argument, an external argument or a semantic adjunct. All cases manifest the same patterns, which are related to the denotative meanings included in the agent polysemy: Agent, Instrument, Locative, Action, Result and Cause. Our contrastive analysis shows that the same patterns are found in the four Swedish agentive formations, [N/A/Adv/PV-are]<sub>N</sub>, [N/A/Adv/PV]<sub>N</sub>, [N/A/Adv/PV-a]<sub>N</sub> and [VN]<sub>N</sub>, which correspond to the French [VN/A/Adv/P]<sub>N/A</sub> construction and which also contain a verbal constituent and its internal or external argument, or an adjunct.</p><p>The second part of our analysis is quantitative and concerns the profitability aspect of productivity. The method is inductive. The aim is to explore the polysemy of agent and its assumed hierarchical structure, in synchrony and diachrony. Four French agentive formations, [VN/A/Adv/P]<sub>N/A</sub> compounds and V-<i>ant</i>, V-<i>eur</i> and V-<i>oir</i>(<i>e</i>) derivations, are included in order to examine semantic competition and blocking effects. Our results give evidence for the existence of an agent polysemy but deny that it has a hierarchical structure valid for every agentive formation. The meanings in the agent polysemy are more or less profitable according to formation type: blocking effects could explain this behaviour.</p>
135

La formation agentive en français: les composés [VN/A/Adv/P]N/A et les dérivés V-ant, V-eur et V-oir(e)

Rosenberg, Maria 04 June 2008 (has links) (PDF)
This study addresses the French morphological construction [VN/A/Adv/P]N/A. The main objectives are to posit a single rule for its formation and to question the implications of the agent polysemy. The theoretical framework is lexeme-based morphology, which adheres to weak lexicalism. The first part of our analysis is qualitative and concerns the availability aspect of productivity. The method is introspective. The internal semantic patterns of the French construction are examined. Our results give evidence for the claim that a single morphological construction rule, [VN/A/Adv/P]N/A, is responsible for the cases where the first constituent is a verb stem, and the second constituent may correspond to an internal argument, an external argument or a semantic adjunct. All cases manifest the same patterns, which are related to the denotative meanings included in the agent polysemy: Agent, Instrument, Locative, Action, Result and Cause. Our contrastive analysis shows that the same patterns are found in the four Swedish agentive formations, [N/A/Adv/PV-are]N, [N/A/Adv/PV]N, [N/A/Adv/PV-a]N and [VN]N, which correspond to the French [VN/A/Adv/P]N/A construction and which also contain a verbal constituent and its internal or external argument, or an adjunct. The second part of our analysis is quantitative and concerns the profitability aspect of productivity. The method is inductive. The aim is to explore the polysemy of agent and its assumed hierarchical structure, in synchrony and diachrony. Four French agentive formations, [VN/A/Adv/P]N/A compounds and V-ant, V-eur and V-oir(e) derivations, are included in order to examine semantic competition and blocking effects. Our results give evidence for the existence of an agent polysemy but deny that it has a hierarchical structure valid for every agentive formation. The meanings in the agent polysemy are more or less profitable according to formation type: blocking effects could explain this behaviour.
136

La formation agentive en français. Les composés [VN/A/Adv/P]N/A et les dérivés V-ant, V-eur et V-oir(e)

Rosenberg, Maria 04 June 2008 (has links) (PDF)
This study addresses the French morphological construction [VN/A/Adv/P]N/A. The main objectives are to posit a single rule for its formation and to question the implications of the agent polysemy. The theoretical framework is lexeme-based morphology, which adheres to weak lexicalism. The first part of our analysis is qualitative and concerns the availability aspect of productivity. The method is introspective. The internal semantic patterns of the French construction are examined. Our results give evidence for the claim that a single morphological construction rule, [VN/A/Adv/P]N/A, is responsible for the cases where the first constituent is a verb stem, and the second constituent may correspond to an internal argument, an external argument or a semantic adjunct. All cases manifest the same patterns, which are related to the denotative meanings included in the agent polysemy: Agent, Instrument, Locative, Action, Result and Cause. Our contrastive analysis shows that the same patterns are found in the four Swedish agentive formations, [N/A/Adv/PV-are]N, [N/A/Adv/PV]N, [N/A/Adv/PV-a]N and [VN]N, which correspond to the French [VN/A/Adv/P]N/A construction and which also contain a verbal constituent and its internal or external argument, or an adjunct. The second part of our analysis is quantitative and concerns the profitability aspect of productivity. The method is inductive. The aim is to explore the polysemy of agent and its assumed hierarchical structure, in synchrony and diachrony. Four French agentive formations, [VN/A/Adv/P]N/A compounds and V-ant, V-eur and V-oir(e) derivations, are included in order to examine semantic competition and blocking effects. Our results give evidence for the existence of an agent polysemy but deny that it has a hierarchical structure valid for every agentive formation. The meanings in the agent polysemy are more or less profitable according to formation type: blocking effects could explain this behaviour.
137

La formation agentive en français : les composés [VN/A/Adv/P]N/A et les dérivés V-ant, V-eur et V-oir(e)

Rosenberg, Maria January 2008 (has links)
This study addresses the French morphological construction [VN/A/Adv/P]N/A. The main objectives are to posit a single rule for its formation and to question the implications of the agent polysemy. The theoretical framework is lexeme-based morphology, which adheres to weak lexicalism. The first part of our analysis is qualitative and concerns the availability aspect of productivity. The method is introspective. The internal semantic patterns of the French construction are examined. Our results give evidence for the claim that a single morphological construction rule, [VN/A/Adv/P]N/A, is responsible for the cases where the first constituent is a verb stem, and the second constituent may correspond to an internal argument, an external argument or a semantic adjunct. All cases manifest the same patterns, which are related to the denotative meanings included in the agent polysemy: Agent, Instrument, Locative, Action, Result and Cause. Our contrastive analysis shows that the same patterns are found in the four Swedish agentive formations, [N/A/Adv/PV-are]N, [N/A/Adv/PV]N, [N/A/Adv/PV-a]N and [VN]N, which correspond to the French [VN/A/Adv/P]N/A construction and which also contain a verbal constituent and its internal or external argument, or an adjunct. The second part of our analysis is quantitative and concerns the profitability aspect of productivity. The method is inductive. The aim is to explore the polysemy of agent and its assumed hierarchical structure, in synchrony and diachrony. Four French agentive formations, [VN/A/Adv/P]N/A compounds and V-ant, V-eur and V-oir(e) derivations, are included in order to examine semantic competition and blocking effects. Our results give evidence for the existence of an agent polysemy but deny that it has a hierarchical structure valid for every agentive formation. The meanings in the agent polysemy are more or less profitable according to formation type: blocking effects could explain this behaviour.
138

視覺意識中的線性與非線性功能連結 / Linear and Nonlinear Functional Connectivity

李宏偉, Lee,Hung-Wei Unknown Date (has links)
意識的議題古老而難解,但是近年來認知神經科學領域對此議題的探討已經熱烈展開,本研究之主要目的即在探索視覺意識與大腦功能性連結之間的關係。 根據一項人臉知覺的實驗結果,本研究依照線性對非線性、局部對整體等兩項條件所構成的四個取向,分別擬定用以反映視覺意識的腦電波指標。結果發現,線性的局部指標—即γ波的強度,以及線性的整體指標—即γ波的相位耦合程度,兩者皆無法有效反映視覺意識。然而,非線性的局部指標—即吸子的相關維度,在特定通道上可以反映視覺意識;至於非線性的整體指標—即廣義的同步化程度,乃為四者中最能穩定反映視覺意識的指標。 除了得到上述若干可以有效反映視覺意識的腦電波指標之外,本研究實質上整合了認知神經科學、非線性動力系統理論、小波轉換理論以及小世界理論等當代思維,因此文中亦做出大量而深入的理論探討,並且提出對現有相關研究在邏輯或方法上的改進與澄清。 / Consciousness is an ancient and puzzling mystery. Until recently, scientists have made little significant progress on it. This study is aimed to search for the neural correlates of visual awareness. / Based on empirical data from an experiment of face perception, this study explores linear vs. nonlinear and local vs. global human EEG indexes of visual awareness. The results indicate that neither linear local index, i.e. γ-band power, nor linear global index, i.e. γ-band phase coherence, can reveal the participant’s state of awareness validly. However, nonlinear local index, i.e. correlation dimension of attractor, can be a valid index of visual awareness, but only on specific channels. Last but not least, nonlinear global index, i.e. generalized synchrony, can be the most valid and efficient index of visual awareness. / In addition to the empirical findings listed above, this study, an interdisciplinary combination of cognitive neuroscience, chaos theory, wavelet transform and small-world theory, also presents numerous theoretical discussions and modifications to other related studies logically or methodologically.
139

Estádio de maturação dos frutos, tratamentos pré-germinativos e variabilidade da emergência de plântulas de morototó (Schefflera morototoni)

Anastácio, Maristela Rosália 25 February 2010 (has links)
The objective of this work was to evaluate the influence of the fruit maturation stage in the physical attributes and germination of Schefflera morototoni pyrenes subjected to pre-germination treatments. Fruits with green and purplish green coloration were collected from 14 individuals, pulped in running water, the hollow pyrenes were discarded after counting, together with those presenting retracted and oxidized endosperm, using the uniforms (with the greenish endosperm occupying the whole cavity of the pyrene). The experiment was conducted in completely randomized design in a 2 x 5 factorial (stages of fruit maturation and pre-germination treatments), with four repetitions in plots containing 25 pyrenes. For greater capacity and germination speed of the pyrenes, fruits should be harvested when they present a purplish green coloration, discarding those with hollow pyrenes, with retracted or oxidized endosperm. The germination capacity of the pyrenes with uniform endosperm varied between 50 and 60%, with the beginning of the process at about 40 days after sowing and extending for up to 60 days in vermiculite. Pulped pyrenes, dried and soaked in water at 60ºC for 5 minutes, followed by soaking in water at room temperature for 12 hours begin the germination process in less time, in relation to those pulped, dried, scarified and soaked for 6 hours. The fruit endocarp is permeable and rigid; however, it presents a natural opening when soaked. The objective was to evaluate the variability in seedling emergence measures of Schefflera morototoni from pyrenes of different individuals. Fruits of 14 individuals were pulped and pyrenes with uniform endosperm were selected. The experiment was conducted in completely randomized design with 14 treatments (individuals) and 11 repetitions in parcels containing 50 pyrenes with uniform endosperm treated by immersion in water at 60 ºC for 5 minutes and then soaked at room temperature for 12 hours. The substrate used was a mixture in proportion 2:1:1:1/2 (v/v) soil, commercial substrate Bioplant®, coarse sand and vermicompost, with pyrenes sown at 1 cm depth in expanded polystyrene trays, maintained in a nursery with 50% reduction in luminosity at average temperatures of 19.3ºC minimum and 30.2 ºC maximum and daily irrigation. Daily counting of seedlings evaluated capacity, time, rate, uniformity and synchrony of emergence, besides the distribution of frequency of emergence in relation to time. The emergence of seedlings is slow, irregular and asynchronous, taking more than 80 days for stabilization of the emergence. The percentage of seedlings can reach up to 57%, but even when the endosperm occupies the whole cavity of the pyrene and is greenish, the emergence of seedlings may not occur. There is variability in seedling emergence measurements from pyrenes of different Schefflera morototoni individuals. / CAPÍTULO II: O objetivo do trabalho foi avaliar a influência do estádio de maturação dos frutos nos atributos físicos e de germinação de pirênios de Schefflera morototoni submetidos a tratamentos pré-germinativos. Frutos com coloração verde e verde-arroxeada foram coletados de 14 indivíduos, despolpados em água corrente, descartando-se, após contabilização, os pirênios chochos, com endosperma retraído e oxidado, utilizando-se os uniformes (com endosperma esverdeado ocupando toda a cavidade do pirênio). O delineamento experimental foi o inteiramente casualizado em esquema fatorial 2 x 5 (estádios de maturação dos frutos e tratamentos pré-germinativos), com quatro repetições em parcelas contendo 25 pirênios. Verificou-se que para maior capacidade e velocidade de germinação dos pirênios, os frutos devem ser colhidos quando apresentarem coloração verde-arroxeada, descartando-se àqueles com pirênios chochos, endosperma retraído ou oxidado. A capacidade de germinação dos pirênios com endosperma uniforme varia entre 50 e 60%, com início do processo em cerca de 40 dias após semeadura, se estendendo por até 60 dias em vermiculita. Pirênios despolpados, secos e embebidos em água a 60oC por 5 minutos, seguida da embebição em água à temperatura ambiente por 12 horas iniciam o processo de germinação em menor tempo, em relação aos despolpados, secos, escarificados e embebidos por 6 horas. O endocarpo dos frutos é permeável e rígido, no entanto, apresenta abertura natural quando embebido. CAPÍTULO III: O objetivo foi avaliar a variabilidade nas medidas de emergência de plântulas de Schefflera morototoni provenientes de pirênios de diferentes indivíduos. Frutos de 14 indivíduos foram despolpados, selecionando-se pirênios com endosperma uniforme. O experimento de emergência foi conduzido em delineamento inteiramente casualizado com 14 tratamentos (indivíduos) e 11 repetições em parcelas contendo 50 pirênios com endosperma uniforme imersos em água a 60 ºC por 5 minutos e posteriormente embebidos em água destilada à temperatura ambiente por 12 horas. O substrato utilizado foi uma mistura na proporção 2:1:1:1/2 (v/v) de solo, substrato comercial Bioplant®, areia de textura grossa e vermicomposto, com pirênios semeados a 1 cm de profundidade em bandejas de poliestireno expandido, mantidas em viveiro com sombrite de 50% de redução luminosa e médias de temperaturas de 19,3 ºC a mínima e 30,2 ºC a máxima e irrigadas diariamente. Das contagens diárias das plântulas emergidas foram avaliadas medidas de capacidade, tempo, velocidade, uniformidade e sincronia de emergência, além da distribuição de frequência percentual de emergência em relação ao tempo. A emergência das plântulas é tardia, irregular e assíncrona, gastando mais de 80 dias para estabilização do estande. A porcentagem de plântulas emergidas pode atingir até 57%, porém mesmo quando o endosperma ocupa toda a cavidade do pirênio e está esverdeado, a emergência das plântulas pode não ocorrer. Há variabilidade nas medidas de emergência de plântulas quando obtidas de pirênios de indivíduos distintos de Schefflera morototoni. / Mestre em Agronomia
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Dynamique spatio-temporelle des populations de truites en milieu naturel et au voisinage des ouvrages hydroélectriques / Spatiotemporal dynamics of brown trout populations in natural and bypassed reaches

Bret, Victor 04 May 2016 (has links)
Bien que l’écologie de la truite (Salmo trutta) ait déjà été bien étudiée, les processus expliquant la dynamique spatio-temporelle des populations restent à caractériser. L’objectif de cette thèse était d’identifier les processus démographiques (ex. survie ou déplacements) et l’influence des processus biotiques (interactions entre individus) et abiotiques (conditions environnementales) qui structurent dans le temps et dans l’espace les différentes classes d’âge (alevins, juvéniles et adultes) de ces populations. J’ai étudié l’influence sur la survie apparente de (1) la densité-dépendance et (2) des conditions environnementales vécues directement par les truites (habitat hydraulique et température de l’eau). Pour évaluer la transférabilité des résultats, j’ai évalué (3) l’échelle spatiale (globale ou locale) à laquelle opéraient les processus et (4) si ces processus variaient entre populations (approche hiérarchique). J’ai considéré la dynamique de 45 populations de truites dont 22 sont situées à l’aval d’un ouvrage hydroélectrique. A large échelle, il est apparu que le recrutement de populations séparées par des distances allant jusqu’à 75km peut être synchronisé par de fortes crues lors de l’émergence des alevins ou des déplacements du substrat de ponte. Nous avons synthétisé les résultats de l’application d’un modèle déterministe de dynamique de population, calibrés localement sur neuf stations aux conditions environnementales bien caractérisées. Cette synthèse a montré que des processus locaux influençaient directement la dynamique des populations. Enfin, la construction d’un modèle hiérarchique a montré le rôle structurant de la mortalité densité-dépendante des juvéniles et des adultes, dont l’intensité augmentait en l’absence d’abris (<2% de la surface) ou variait avec la température de l’eau (diminution pour les juvéniles et augmentation pour les adultes). Ce travail fournit des bases scientifiques aux gestionnaires d’ouvrages hydro-électriques pour leur permettre de limiter leur influence sur les populations de poissons et répondre ainsi aux demandes réglementaires / Brown trout (Salmo trutta) ecology was largely studied. However, the process structuring the spatiotemporal patterns of population dynamics remains unclear. The objective of this thesis was to identify the demographic processes (e.g. survival or displacements) and the influence of biotic (between-individuals interactions) and abiotic (environmental conditions) processes structuring the age-stages (fry, juveniles and adults) of these populations in time and space.I studied (1) the role of density-dependence on survival and (2) the influence of environmental conditions experienced by trouts (hydraulics and water temperature). To assess the results’ transferability, I studied (3) the spatial scale (global or local) of influence of the processes and (4) if those processes varied among populations (hierarchical approach).I considered the dynamics of 45 trout populations, 22 being located downstream a hydropower facility. At a large scale, the recruitment of distant populations (up to 75 km apart) may be synchronized by large floods during emergence of fry or by spawning substratum displacements. We summarized the results of a determinist population dynamics models, locally calibrated on nine reaches showing well-described environmental conditions. This summary revealed the influence of various local drivers on population dynamics. Finally, a hierarchical model showed that density-dependent mortality among juveniles and adults was a key biotic process. The strength of the competition was greater in absence of shelter (<2% of the surface) and varied with water temperature (decreasing for juveniles and increasing for adults).The results of this work will provide scientific basis to hydropower facility managers. This will help them to reduce their influence on trout populations and respond to regulatory demands

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