Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Tese de mestrado. Manutenção Industrial. 2005. Faculdade de Engenharia. Universidade do Porto

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Thesis (Ph. D.)--University of Sydney, 2004. / Title from title screen (viewed 5 May 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Veterinary Science. Degree awarded 2004; thesis submitted 2003. Includes bibliographical references. Also available in print form.

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains vii, 91 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

The major aim of the experiments described in this thesis was to investigate the putative mechanisms that are involved in the control of B- endorphin (B-END) secretion into the peripheral blood of the Soay ram. In addition, the effect of 8-END and adrenocorticotrophin (ACTE1) on cortisol secretion was investigated. A series of experiments was carried out to assess the influence of season, photoperiod, melatonin implantation, pinealectomy, castration and testosterone replacement on B-END secretion. There were significant changes in the plasma concentrations of B-END related to season and photoperiod in rams kept outside and inside, respectively. In outdoor rams B-END levels were highest in autumn and lowest in winter; in indoor rams the levels were highest during short days and lowest during long days. Melatonin implantation in outdoor rams from May to August caused a significant increase in B-END secretion, indicating a melatonin-induced short-day effect inspite of the prevailing long days. Pinealectomy disrupted the seasonal cycle in B-END secretion. Castration and testostrone replacement in indoor rams did not influence B-END secretion. These results indicate that B-END secretion is strongly influenced by season and photoperiod (via melatonin from the pineal gland) and that testosterone plays no role in B-END secretion. In another series of experiments, the roles of arginine vasopressin (AVP), corticotrophin releasing factor (CRF), the synthetic glucocorticoid, dexamethasone (DEX) and the synthetic glucocorticoid antagonist, RU 486, in the control of the seasonal cycle in B-END secretion were investigated in spring, summer, autumn and winter. AVP and CRF given alone or in combination significantly stimulated 8-END secretion at all seasons and acted synergistically when given together. The responses were greater in summer and autumn than in winter and spring. DEX suppressed 8-END secretion at all seasons and the responses were also greater in summer and autumn. DEX also blocked the AVP-induced increase in 8-END secretion, indicating an action of DEX at the pituitary gland. RU 486 given in summer and winter significantly stimulated 8-END secretion only in winter, indicating a seasonal variation in the negative feedback action of endogenous glucocorticoids. In addition, ACTH, but not 8-END, significantly stimulated cortisol secretion at all seasons, with the greatest response in spring. These studies indicate that AVP, CRF and glucocorticoids are involved in the control of the seasonal cycle in 8-END secretion; and that ACTH rather than 8-END constitutes the " drive " to cortisol secretion. The roles of dopamine (DA) and endogenous opioid peptides (EOP) in the control of 8-END secretion were also investigated. The mixed DA antagonist, pimozide, significantly increased 8-END secretion under long and short days; with a greater effect under long days. The D2 agonist, bromocriptine, and the D2 antagonist, sulpiride, significantly decreased and increased, respectively, 8-END secretion both under long and short days. The opioid antagonist, naloxone, had no effect on 8-END secretion. These studies indicate that DA exerts an inhibitory control over 8-END secretion while the EOP play no role in 8-END secretion. Based on the current results and a survey of the relevant literature, a model is proposed in which AVP, CRF, glucocorticoids on one hand, and DA on the other hand, are involved in the control of the secretory activity of corticotrophs and melanotrophs in the pituitary gland. These central mechanisms are influenced by changes in photoperiod and other environmental factors to dictate the seasonal cycle in 6-END secretion in the Soay ram, which is low in winter and high in autumn. To fully assess the importance of AVP, CRF and DA in the seasonal control of 6-END secretion, it will be necessary to directly measure the concentration of these hormones in the hypophysial portal circulation of Soay rams at different seasons.

SANTOS, Antônio Carlos Santana dos. Caracterização da Microfísica das Nuvens sobre a Amazônia Brasileira em Regiões de Pasto e Floresta Medida em Situ por Avião Instrumentado e sua Aplicação Direta no Modelo Regional Rams. 2005. 159 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2005. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-06-18T19:38:31Z No. of bitstreams: 1 2005_tese_acssantos.PDF: 6584804 bytes, checksum: 032023b09866b8ef3557c3accca46784 (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-06-18T19:39:49Z (GMT) No. of bitstreams: 1 2005_tese_acssantos.PDF: 6584804 bytes, checksum: 032023b09866b8ef3557c3accca46784 (MD5) / Made available in DSpace on 2015-06-18T19:39:49Z (GMT). No. of bitstreams: 1 2005_tese_acssantos.PDF: 6584804 bytes, checksum: 032023b09866b8ef3557c3accca46784 (MD5) Previous issue date: 2005 / Improving or knowledge on cloud microphysics is fundamental to understand the clouds dynamics, its role in the atmospheric general circulation and energy balance, as well as in weather and climate prediction applications using large-scale and mesoscale models. This work aims to verify the dynamic and microphysical behavior of clouds over the Amazon basin and, in particular, to compare those behaviors over pasture and forest areas in Rondônia State. Several thermodynamic and microphysics measurements obtained in situ with the University of North Dakota instrumented aircraft (Citation II) were analyzed, allowing us to reach some conclusions about the microphysical and dynamical characteristics of clouds over pasture and forest areas. Cloud-resolving simulations using RAMS model (Regional Atmospheric Model System) were performed in order to assess sensitivities regarding vegetation cover (pasture or forest). The simulations did not show significant differences in the average vertical profiles of cloud microphysics variables (such as mixing rations for the different hydrometeor species). On the other hand, simulations using different model setups (changes in initialization or average diameter or droplets concentration), produced significant differences in precipitation and hydrometeor concentration, per exempe. Finally, simulations in which the droplets concentrations were specified showed better agreement with observations obtained during ABRACOS experiment (Anglo-Brazilian Amazonian Climate Observation Study), than simulations in which average diameter were specified. / Conhecer a microfísica de nuvens é fundamental para o entendimento da dinâmica, bem como a sua aplicação direta em modelos regionais de tempo e clima. O trabalho proposto nesta tese tem o objetivo de verificar o comportamento dinâmico e microfísico de nuvens amazônicas e, em particular, comparar esse comportamento para nuvens sobre as regiões de pasto e floresta no Estado de Rondônia. Diversas medidas termodinâmicas e microfisicas obtidas in situ com o avião laboratório Citation II foram analisadas, sendo possível extrair algumas conclusões relativas ao comportamento microfísico das nuvens formadas sobre pasto e floresta. Também foram feitas diversas simulações com o modelo RAMS (Regional Atmospheric Model System): testes de sensibilidade em relação à cobertura vegetal (pasto ou floresta), que não apresentaram diferenças significativas no perfil vertical da microfísica das nuvens; simulações feitas inicializando o modelo com o diâmetro médio ou com a concentração de gotículas, cujos resultados apresentaram diferenças significativas. Os resultados obtidos nas simulações inicializadas com a concentração de partículas mostraram-se bastante próximos daqueles observados durante o experimento ABRACOS (Anglo-Brazilian Amazonian Climate Observation Study).

Dans un contexte de changement climatique, les impacts attendus sur les terroirs viticoles posent un certain nombre de questions, notamment sur les risques encourus (variation des caractéristiques et de la qualité du vin) et les enjeux. Ce travail de thèse vise à mettre en place une méthodologie de mesures et de modélisation spatiale de la température, dans les terroirs viticoles du Val de Loire, afin de définir le climat actuel et d’apporter des réponses aux conséquences futures du changement climatique à l’aide de simulations adaptées. Une étude diagnostic des données de températures régionales a préalablement été effectuée et montre une augmentation généralisée de la température et des indices bioclimatiques de la vigne depuis 1950. Des expérimentations à échelles locales ont été réalisées dans les terroirs viticoles de la moyenne vallée de la Loire grâce à un important dispositif de mesures climatiques. La variabilité spatiale de la température est notamment mise en évidence par l’étude d’indices bioclimatiques comme les degrés-jours qui montrent des différences parfois comparables à celles observées à l’échelle régionale. Une modélisation multicritères a été appliquée sur un site expérimental des Coteaux du Layon et montre l’importance des facteurs topographiques dans la variabilité de la température. Une dernière étape a permis d’obtenir des simulations du modèle méso-échelle RAMS. Les simulations à 5 km de résolution sur la période de référence 1991-2000 ont été contrôlées sur certains mois clés de la croissance de la vigne puis confrontées aux sorties du modèle ARPEGE-Climat (50 km). Les résultats montrent l’intérêt de la désagrégation d’échelle par le modèle RAMS avec des biais réduits sur les températures, et notamment une meilleure appréhension des extrêmes thermiques. Les simulations de la période future 2041-2050 (Scénario A2) montrent un recul de l’aléa gélif pour le mois d’avril mais une augmentation de la fréquence des journées chaudes (>30°) et très chaudes (>35°C) pendant la période véraison-maturation. Enfin, les simulations de quelques épisodes extrêmes à 200 mètres de résolution ont soulevé toute la complexité de ce type de modélisation, avec des températures plus ou moins bien reproduites selon les journées. / In the context of Climate Change, the potential impacts for viticultural terroirs pose a number of questions, especially the likely risks (variability in wine characteristics and quality) and implied challenges. This thesis aims to develop a methodology for measuring and modeling the spatial variability in temperature in viticultural terroirs of the Loire Valley, in order to define the current climate and to provide some answers about the future consequences of Climate Change. The temperature trends in the Loire Valley have therefore been analysed since the middle of the 20th century, using the regional weather stations network. The results indicate an increase of temperatures and bioclimatic indices for all the regional stations. Experimentations at local scales have been realized in the viticultural terroirs of the middle-Loire Valley thanks to an important network of weather stations and data loggers. Bioclimatic indices, as the growing-degree days, underline the spatial variability in temperature and show that this variability can sometimes be as significant at fine scale as at larger scales. A multicriteria modeling has been applied on an experimental site in the Coteaux du Layon vineyards and highlights which local factors prevail in the temperature variability. Climatic modeling has been carried out at fine scales in the last stage of this study with the Regional Atmospheric Modeling System (RAMS). Downscaled simulations delivered at high resolution (5 km resolution) for the control period (1991-2000) were compared with ARPEGE-Climat simulations (50 km) for a few important months during vine growth. Results showed that RAMS contributed to reducing the large-scale induced bias and gave better simulations of extremes temperatures. The RAMS assimilation of the SRES A2 scenario for the 2041-2050 period projected frost risk to decrease in April but an increase in the frequency of hot days (>30°C) and very hot days (>35°C) during veraison and berry ripening. Finally, extreme weather simulations revealed all the complexity of this kind of modeling, with contrasted results according to the different simulated days

Graduation date: 1998