Testicular morphology in Corriedale rams : influence of feeding management under extensive rearing conditions in the Río de la Plata grasslands /Bielli Pallela, Alejandro. January 1900 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.
Tese de mestrado. Manutenção Industrial. 2005. Faculdade de Engenharia. Universidade do Porto
No description available.
Flow-cytometric sorting of ram spermatozoa production of lambs of a pre-determined sex using in vivo and in vitro fertilisation /Hollinshead, Fiona Kate. January 2003 (has links)
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.
Chavez, Stephen John.
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.
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 RamsSantos, Antônio Carlos Santana dos January 2005 (has links)
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 (firstname.lastname@example.org) 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(email@example.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).
Experimental actinobacillus seminis infection of rams : a scanning electron microscopy study of seminal vesiclesStockinger, Helmut F January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
Influence of castration and estrogen replacement on sexual behavior in hetersexual, male-oriented and asexual ramsPinckard, Kelly Lynn 08 May 1998 (has links)
Graduation date: 1998
Korres, Geōrgios Styl.
Thesis (doctoral)--Ethnikon kai Kapodistriakon Panepistēmion Athēnōn, Philosophikē Scholē. / Summary in English. Includes bibliographical references (p. xx-xxviii) and index.
Page generated in 0.0465 seconds