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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.
101

Foraging Ontogeny in an Urban Population of Black Phoebes (Sayornis Nigricans)

Baker, Jessica N 01 January 2013 (has links)
The ability to forage successfully is intimately tied to juvenile survivorship in many avian species. The time it takes juveniles to develop competent foraging skills varies with the prey type and foraging behaviors. My research examined the length of time it took juvenile Black Phoebes (Sayornis nigricans), a bird species abundant in urban environments, to exhibit foraging behavior similar to adults. Black phoebes are insectivorous and forage by scanning for and then pursuing potential prey. I hypothesized that before they disperse, approximately two months after fledging, juvenile phoebes should forage as successfully as adults. Because foraging proficiency affects time allocation, the study also compared how juveniles spend their time compared to adults. In support of my hypothesis, when juveniles were five weeks old, they foraged as successfully as adults. However, by the time of dispersal juveniles did not allocate their time similarly to adults, spending more time flying and less time perched than adults. Finally, the scanning rate and duration of foraging flights were similar to adults after the second week of successful foraging (around week six of age). Overall, these results indicate that foraging is a learned behavior that juveniles develop during their first few months of independence. Early development of proficient foraging abilities increases chances of survival. However, the development of proficient foraging abilities appears to precede the development of effective time allocation, which must occur sometime after independence.
102

DRUG MILK TO SERUM RATIO PREDICTION AND ONTOGENY OF CYP3A CLEARANCE PATHWAY AS A MODEL OF DRUG EXPOSURE IN THE DEVELOPING RAT

Abbassi, Maggie Magdi 01 January 2007 (has links)
Transfer of drugs into milk and the clearance of drugs in neonates are critical determinants of the exposure of infants to drugs in breast milk. Models predicting both parameters have been proposed. The objective of this dissertation is to test two models predicting milk to serum ratio and an ontogeny clearance model predicting clearance in the neonate. Predicted milk to serum ratio (M/S) values were generated according to the Atkinson and Begg model. The model did not adequately predict M/S when comparing the predicted values to observed values in the literature. The Fleishaker model was also tested. The model was able to predict whether the drugs appeared in milk by passive diffusion only or whether active transport processes were involved. This model, together with appropriate animal models, is useful in understanding the mechanism of drug transfer into milk. An ontogeny model that predicts clearance was proposed earlier by our laboratory. In order to test the model prediction and assumptions of constant microsomal protein and constant Km for an enzyme-substrate system with age, the male rat was used as an animal model. The ontogeny of Cyp3a1, Cyp3a2, Mdr1a and Mdr1b mRNA was examined in the male rat liver and intestine. The ontogeny pattern of Cyp3a2 mRNA, protein and in vitro Cyp3a activity were found to be similar in male rat liver. The microsomal protein content was found to vary with age in the liver. Km was found to be constant with age for the midazolam 4-hydroxylation by male rat liver microsomes. Scaling factors that extrapolate adult clearance to infant clearance were calculated from in vitro data. The model did not predict the in vivo oral clearance of midazolam for day 7 and 21 age groups from the 112 day age group (adult). The assumption that intestinal availability in the rat pups and adults was equal to unity might not be true resulting in overprediction of rat pup clearance when compared to the adult. Intestinal first pass effect for midazolam in adult rats might be significant. More experiments are needed to further test the model adequacy in clearance prediction.
103

The role of climate in determining the ontogeny trends of low Arctic lakes, south-western Greenland

Liversidge, Antonia C. January 2012 (has links)
This thesis uses palaeolimnological records to reconstruct Holocene ontogeny trends from four lakes in south western Greenland. The research addresses four hypotheses investigating how Holocene lake ontogeny trends vary under different climatic settings, how long-term changes in ontogeny relate to periods of established climatic change in the region, the similarities between proxies within the lakes and between the lakes, and the role of vegetation in lake ontogeny. The study region occupies the widest ice-free area of south western Greenland and is characterised by a climatic gradient. The area inland and nearer to the ice-margin is arid, receives less precipitation and is warmer relative to the coastal areas. A paired lake approach, using lake records from two inland lakes and two coastal lakes, was adopted to examine the role of climatic setting upon lake development trajectories. Specifically, diatoms were used to reconstruct DI-alkalinity from the lakes using a DI-alkalinity model created from existing training sets in the region (WA Cla model, r2boot = 0.76, RMSEP = 0.28 log alkalinity units), sedimentary pigments to investigate trends in production and sedimentary parameters to reconstruct organic and minerogenic accumulation rates. All four lakes experienced comparable Holocene long-term ontogeny trajectories; maximum alkalinity in the first ~ 1000 cal. year BP of deglaciation followed by maximum production during the peak of Holocene Thermal Maximum (HTM) warming (~7000 -6000 cal. years BP). Following the HTM, all lakes demonstrated oligotrophication and a decline in pH. Vegetation development and catchment stabilisation at the end of the HTM may be important in determining the onset of oligotrophication in vegetated catchments. However, the impact of vegetation development on lake ontogeny cannot be isolated from the changes in the lakes associated with the colder and wetter climate which occurred at the end of the peak HTM warming. The timings of the large transitions in the ontogeny trajectories are comparable with established periods of Holocene climatic variability in the region; climate forcing drives ontogeny in these lakes. However, there are short-term differences between the lakes indicating that lakes have different thresholds of ecological change and may respond differently to the same climate forcing. It is concluded that ontogeny is driven by climate but lakes may respond differently to forcing depending on catchment specific characteristics which can filter out the climate signal or cause climate to influence the lake in a more direct way.
104

Behavioural phenotypes : associated life-history traits and environmental effects on development

Edenbrow, Mathew January 2011 (has links)
It is widely documented that non-human organisms express individual differences in behavioural patterns. For example individuals can be categorised as bold or shy and when these individual behavioural differences are consistent through time, they are termed behavioural types (BTs). In recent years research has identified that BTs often correlate across contexts/situations and these correlations are referred to as behavioural syndromes. Behavioural types and syndromes (i.e. personality) have also been implicated as major factors shaping population dynamics and the ability to buffer environmental disturbance. Recent theoretical predictions have proposed that BT variation may be underpinned by life-history strategies; however, these predictions have been little studied to date. Moreover, little research has focused upon environmental influences and the ontogeny of personality. In this thesis I use the Mangrove killifish (Kryptolebias marmoratus), a naturally occurring clonal vertebrate, as a model organism. This species presents a powerful tool providing the ability to replicate within and between isogenic genotypes in a controlled manner. Moreover the natural clonality expressed by this species permits environmental effects upon BT plasticity and BT-life-history interactions to be investigated within a developmental framework. In chapter 2, I present microsatellite genotyping results which show that the founding individuals used to propagate a laboratory population at The University of Exeter represent 20 genetically distinct homozygous genotypes. I additionally address five research questions exploring genotypic, environmental, and developmental effects upon three commonly studied BTs (exploration, boldness and aggression): Firstly; I ask do adult hermaphrodite and secondary males exhibit personality i.e. repeatable BT expression? In chapter 3, I present results showing that both of the sexes express short term personality. Moreover, I show that that genotype is an important factor influencing BTs expressed, regardless of sex, indicating underlying genetic control. Secondly I ask; does genotype level life-history variation underpin personality trait variation during ontogeny? In chapter 4, I show considerable developmental plasticity in behavioural expression between genotypes but not life-history and I find limited behaviour-life-history relationships during development. Thirdly I ask; does the rearing environment influence life-history and behavioural plasticity? In chapter 5, I show that in comparison to a control treatment, the presence of conspecifics during ontogeny results in an average reduction in behavioural scores; however, life-history was unaffected. In addition, I show that development in a low food environment lowered average exploration and growth rate but had no effect on boldness or aggression. Furthermore, fish exposed to a predation risk simulation during ontogeny exhibited similar behavioural scores as the control, yet this treatment generated BTs i.e. personality. My fourth question asks; does the parental rearing environment (utilised in chapter 5) influence behavioural expression in the next generation? In chapter 6, I show that transgeneratonal effects of each parental rearing environment influenced life-history but had a minimal effect upon behaviour in the next generation. Finally I ask; does kin or familiarity influence plasticity in associations and aggression? In chapter 7, I show that genotypes have the ability to discriminate kin and familiars and modulate aggression and association accordingly. These results support the concept that developmental and environmental induced plasticity may be more important than life-history in shaping behaviour. Furthermore, although adults exhibit personality and genotypic effects appear important, genotype interacts with environmental/experiential influences to differentially shape behavioural plasticity during ontogeny. I suggest that theoretical predictions regarding life-history may be insufficient to explain the complexity of animal personality in this species. I discuss these results within developmental and epigenetic frameworks with reference to the ecological significance of these patterns within this species and the animal kingdom as a whole.
105

Morphologie, morphométrie et systématique des coraux plocoïdes jurassiques (sous-ordre Stylinina) / Morphology, morphometry and systematics of plocoid Jurassic corals (suborder Stylinina)

Zaman, Shaahin 10 February 2012 (has links)
Une nécessaire révision des coraux plocoïdes jurassiques en morphologie, morphométrie, systématique et en nomenclature a été réalisée grâce à des spécimens-types, du matériel de collection, ou issu de la littérature. Des structures dont une nouvelle muraille, l'étallonothèque et des types d'auricules ont été identifiés. Un stade initial ontogénique tétraméral a été observé pour la première fois chez Heliocoenia et Pseudocoenia. Ceci est en désaccord avec la définition traditionnelle sur le développement fondamentalement hexaméral chez les Scleractinia. L'étude systématique aboutit à une réorganisation des familles, des genres et de leurs synonymies. Des espèces sont décrites avec des limites encore parfois ambigües nécessitant une approche morphométrique plus approfondie pour être reproductible. Les positions systématiques prises sont traduites dans le sens de la préservation de la stabilité de l'usage des noms, des actes nomenclaturaux sont proposés dans ce sens. Deux méthodes morphométriques ont été appliquées aux contours 2D des sections de polypiérites. L'analyse de Fourrier Elliptique a été utilisée sur des coupes transversales théoriques et réelles. Les résultats montrent les différentes symétries et certains genres distingués par cette méthode. L'analyse des dimensions fractales de modèles théoriques, des coupes étudiées, ou issues de la littérature ont été analysées. Les formes étudiées se placent selon un gradient de complexité croissante du contour correspondant à la maximisation de l'interface squelette-porosité. Le long de ce gradient, les différents taxons se répartissent, leur distinction restant souvent délicate par suite d'un léger recouvrement / A review of Jurassic plocoid corals in morphology, morphometry, systematics and in nomenclature was necessary. This study was realized with collection materials, type specimens and material from the literature. The morphological study enables identifying structures such as a new type of wall, the etallonotheca and some new types of auricles. A tetrameral initial ontogenetic stage was observed for the first time in Heliocoenia and Pseudocoenia. This is in disagreement with the traditional definition of the septal development supposed to be fundamentally hexameral in Scleractinia. The systematic study led to a significant reorganization of families, genera and their synonyms. Species are described but their limits are still ambiguous and so still require more detailed morphometric approaches to be reproducible. The systematic positions chosen here are translated in terms of nomenclature in order to preserve the stability of names. This requires in various cases nomenclatural acts. Two morphometric methods were applied on 2D contours of calices sections. Elliptical Fourier analysis was used on theoretical and real transversal sections. The results show that the different symmetries and some genera can be distinguished by this method. Analysis of fractal dimensions has also been applied. Theoretical models and the sections studied in this work or issued from the literature were analyzed. The studied forms are placed according to an increasing complexity gradient of the contour corresponding to the maximization of the interface skeleton-porosity. The different taxa are distributed along this gradient, due to their small overlaps; their true distinction often remains difficult
106

Intraindividuální komparace vybraných koordinačních ukazatelů bruslařského kroku na ledě a při in-line / Intraindividual comparison of selected indicators of coordinating steps on the skating step and on the in-line step

Hospůdka, Jakub January 2010 (has links)
4 Summary: Title: Intraindividual comparison of selected indicators of coordinating steps on the ice skating and in-line. Objective: Assessment of coordination relationship rate of the skating forward during ice hockey and inline skating. Methods: Surface electromyography combinated with kinematography analysis used synchronized video recording. Results: Kinesiological content of movement during ice skating and inline skating is not the same. The general stereotype of the skating step is significantly different from the walking stereotype. Key words: human locomotion, sport locomotion, phylogeny, ontogeny, surface electromyography, ice hockey skating, inline skating.
107

Ontogenetický vývoj eokrinoidních ostnokožců kambria barrandienské oblasti / Ontogenetic development of Cambrian eocrinoid echinoderms of the Barrandian area

Nohejlová, Martina January 2013 (has links)
This diploma thesis presents the first study focused on the ontogenetic development of eocrinoid echinoderms in the Czech Republic. Parsley's work (2012) on ontogeny of the genus Gogia from south China is the model study. The aim of this thesis is a comparable study of ontogeny of eocrinoid echinoderms from Cambrian of the Barrandian area. Akadocrinus jani Prokop, 1962 was studied. Using detailed morphological description and measurement of various parameters, three different ontogenetic stages have been established: juvenile ontogenetic stage, mature ontogenetic stage and gerontic ontogenetic stage. Thecal height is the deciding factor for the determination of the specific ontogenetic stage. Further, during ontogeny of this species some trends in changes in the size of body parts are observed (e.g., changes in the diameter of thecal plates). In-depth study of morphological details showed that the originally distinguished two species, Akadocrinus jani Prokop, 1962 and Akadocrinus nuncius Prokop, 1962, represent one species only. Keywords: eocrinoid echinoderms, Akadocrinus jani, ontogeny.
108

Tomographie à rayons X; analyse et modélisation de l'ontogénèse des épicormiques du chêne sessile (Quercus petraea (L.) Matt.). / RX tomography, analysis and modeling of epicormic ontogeny in sessile oak (Quercus patraea (L.) Matt.).

Morisset, Jean-baptiste 11 December 2012 (has links)
Le chêne sessile (Quercus petraea) est une essence majeure de la sylviculture française. Sa ramification, phénomène de mise en place des rameaux, a pour origine unique les bourgeons proventifs axillaires mis en place lors de l'élongation des pousses annuelles (PA). On distingue la ramification séquentielle (les branches séquentielles) et la ramification épicormique. L'ontogénèse des épicormiques, c'est-à-dire le passage d'un bourgeon épicormique à un rameau épicormique plus complexe tel qu'un gourmand, picot ou broussin est encore peu connue. Les rameaux laissent dans le bois des marques, les traces raméales, qui peuvent fortement déprécier la qualité du bois. Etudier l'ontogénèse des rameaux épicormiques du chêne passe par un suivi longitudinal ou une analyse rétrospective des PA, ou par une dissection de l'arbre et une observation des traces raméales. Pour s'affranchir de ces méthodologies fastidieuses nous avons utilisé la tomographie à rayons X qui permet une étude exhaustive de toutes les traces raméales d'un billon, de leur ontogénèse ainsi que la reconstruction du billon en 3D. Les études menées au cours de cette thèse ont permis de mettre en évidence un important effet de l'arbre qui confère à chacun d'entre eux sa propre capacité à mettre en place et maintenir des épicormiques. Plus un arbre présente d'épicormiques dans son jeune âge, plus il en présentera quelques années plus tard. Cette tendance est modulée par la sylviculture actuelle, comme le maintien d'une végétation d'accompagnement qui joue sur les réserves en eau et carbohydrates de l'arbre, et la sylviculture passée, notamment les éclaircies fortes ayant favorisé les émissions de gourmands. Cependant la sélection précoce des arbres objectifs présentant le moins de formations épicormiques est une recommandation sylvicole de première importance dans le but de produire davantage de bois d'œuvre de la meilleure qualité possible. Une stratégie d'intégration de ces résultats dans le simulateur de croissance Fagacée est proposée. / Sessile oak (Quercus petraea) is a major tree species of the French forestry. Its branching, i.e. the phenomenon of twigs implementation, has a unique origin: the proventitious axillary buds set during the annual shoot (AS) elongation. We distinguish the sequential branching and the epicormic branching. Epicormic ontogeny, i.e. transition from a bud to a more complex epicormic twig as an epicormic shoot, a picot or a burl is still little known. The mark left by these twigs in the wood, the rameal trace, can depreciate its commercial value. The study of the epicormic twigs ontogeny is possible with a longitudinal follow-up or a retrospective analysis of an AS, or a dissection of the tree and an observation of the rameal traces. To free ourselves from these tedious methodologies, we used RX computed tomography which allows an exhaustive survey of all the rameal traces of a log, their ontogeny as well as the 3D reconstruction of the log. This PhD allowed to show the important effect of the tree which confers on each one its capacity to set up and maintain epicormics. The more numerous the epicormics were at young stage, the more numerous the epicormics are several years later. This trend is modulated by the actual forest operations, as the maintaining of an accompanying vegetation which play on water and carbohydrates reserve; and by past forest operation as epicormic shoot emission favoured by strong thinning. Nevertheless, the early selection of the crop trees with the few epicormic formations is a silvicultural advice of first importance in order to produce more timber wood of the best quality. A strategy of inclusion of these results in the growth simulator “Fagacées” is proposed.
109

Metabólitos secundários e ontogenia em espécies de Piper / Secondary metabolites and ontogeny in Piper species

Gaia, Anderson Melo 11 December 2014 (has links)
Estudos fitoquímicos em geral são realizados com indivíduos adultos visando isolar e caracterizar substâncias em quantidade para testes de atividade biológica e por isso, há poucos estudos de metabólitos secundários em estágios iniciais do desenvolvimento das plantas. Assim, o trabalho foi realizado com objetivo de analisar o perfil de metabolitos secundários ao longo da ontogenia de espécies do gênero Piper. Os extratos brutos de plântulas e plantas adultas de diversas espécies de Piper foram analisados por técnicas cromatográficas, espectrométricas e espectroscópicas (RMN de 1H, CLAE-UV-EM, CG-EM). Os dados submetidos à análise de componentes principais (PCA) revelaram três grupos, sendo que no primeiro grupo contendo amidas (P. tuberculatum, P. amalago e P. reticulatum) não foi observada diferença significativa no perfil químico nos diferentes estágios de desenvolvimento. No segundo grupo (P. gaudichaudianum, P. solmsianum, P. regnellii, P. caldense e P. hemmendorfii) foi observado o acúmulo de alilfenois nas folhas das plântulas contrastando com as folhas adultas que produziam lignanas, neolignanas ou ácidos benzóicos prenilados. No terceiro grupo (P. richardiaefolium e P. permucronatum) observou-se o predomínio de amidas nas folhas das plântulas enquanto que lignanas ou flavonoides constituem-se nos metabólitos predominantes no estágio adulto. A diferenciação observada na produção de metabólitos secundários ao longo da ontogenia fornece indícios de possíveis estratégias de defesa contra fitopatógenos ou herbívoros. / Phytochemical studies are usually carried out with adult plants for isolation and characterization of compounds in large amounts especially when bioactivity is involved and thus remarkably little is known about the production of secondary metabolites in Piper species at early developmental stages. Therefore, this study was carried out in order to describe the secondary metabolites profile of plants during the ontogeny of the Piper species. Crude extracts from seedlings and adult plants of several Piper species were analyzed by chromatographic, spectrometric and spectroscopic techniques (1H NMR, HPLC-DAD-MS, GC-MS). The analysis with the aid of principal component analysis (PCA) revealed three groups: the first group containing amides (P. tuberculatum, P. amalago and P. reticulatum) no significant differences were observed in the chemical profile at different developmental stages. In the second group (P. gaudichaudianum, P. solmsianum, P. regnellii, P. caldense and P. hemmendorfii) allylphenols were detected as major compounds in the seedling leaves while adult leaves contained lignans, neolignans or prenylated benzoic acids. Additionally, in a third group (P. richardiaefolium and P. permucronatum) amides were observed as major compounds in the seedling leaves instead of lignans or flavonoids found in the adult leaves. The differentiation observed in the secondary metabolite production suggests a plant defensive strategy against phytopathogens and herbivores.
110

Estudo da imunorreatividade da proteína S100<font face=\"symbol\">b no Hipocampo e Núcleo do Trato Solitário de ratos neonatos submetido à anóxia. / Study of S100<font face=\"Symbol\">b protein immunoreactivity in the Hypocampus and Nucleus of Solitary Tract of newborn rats submitted to anoxia.

Allemandi, Wilma 09 February 2012 (has links)
Agressões nos períodos críticos do crescimento do sistema nervoso podem modificar os eventos de desenvolvimento. Entre os vários fatores nocivos está a anóxia. O organismo do neonato tem suprimento de energia anaeróbica relativamente rica, foi observado que a acidose ocorre com menor facilidade, propiciam sobrevivência. A proteína de astrócitos, S100<font face=\"Symbol\">b, exerce efeitos parácrinos e autócrinos em neurônios e glia. Sua estimulação promove sobrevivência e proteção neuronal, atuando como fator trófico e neurotrófico. Modelo animal de anóxia neonatal desenvolvido em nosso laboratório, nos revelou ativação neural pela expressão de Fos e alterações comportamentais, o que nos instigou a explorar os efeitos da anóxia nas células da glia no Hipocampo e Núcleo do Trato Solitário. Para sua exposição à anoxia, durante 25 minutos, foi utilizada câmara, saturada com nitrogênio gasoso 100%. Grupos P2 e P7 nas condições: Basal (B), sem estimulo; Sham (S) como controle experimental e Anóxia (A) com falta de oxigênio, foram analisados por S100<font face=\"Symbol\">b-IR com técnicas ABC/DAB e Western blot. Observamos significante diferença de S100<font face=\"Symbol\">b-IR no núcleo do trato solitário, somente no grupo P2 A 2 h em relação ao grupo P2 S 2 h. A reatividade glial de S100<font face=\"Symbol\">b na formação hipocampal (CA1, CA3+CA2 e DG), apresentou diferença significante no grupo anoxia de acordo com o estágio de maturação do animal. A técnica por Western blot em toda a formação hipocampal, apresentou aumento de S100<font face=\"Symbol\">b no grupo A em ambos P2 e P7, a avaliação de um todo foi diferente daquela de áreas especificas. / Attacks to the nervous system at critical growth periods can modify developmental events. Among the various harmful factors at is anoxia. The high anaerobic energy supply to the newborn and a less easily acidosis occurrence provides survival. The astrocyte S100<font face=\"Symbol\">b protein exerts paracrine and autocrine effects on neurons and glia. Its stimulation promotes neuronal survival and protection, as a trophic and neurotrophic factor. An animal model of neonatal anoxia improved in our lab revealed neural activation by Fos expression and behavioral changes, which prompted us to explore the anoxia effects on glial cells in the Hypocampus and Nucleus of Solitary Tract. For their exposure to anoxia, a chamber, saturated with 100% nitrogen gas, for 25 minutes were used. Groups with P2 and P7, conditions: Baseline, without stimulation; Sham as the experimental control, and Anoxia with lack of oxygen, were evaluated by S100<font face=\"Symbol\">b-IR by ABC/DAB and Western blot techniques. The nucleus of solitary tract, significant different S100<font face=\"Symbol\">b-IR observed, only in the P2 A 2 h compared to P2 S 2 h. The glial S100<font face=\"Symbol\">b-IR at the hippocampal formation (CA1, CA2 + CA3 and DG) presented significant difference in the anoxic group according to the maturational stage of the animal. Western blot technique of the entire hippocampal formation, showed increase of S100<font face=\"Symbol\">b at the group A at both P2 and P7, the whole evaluation was different from of that of specific areas.

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