Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 107-119). Also available on the World Wide Web.

Thesis (M.S.)--Duquesne University, 2003. / Title from document title page. Abstract included in electronic submission form. Includes bibliographical references (p. 65-70) and abstract.

Thesis (Ph. D.)--University of Chicago. / Cover title. Reprinted from the Journal of comparative neurology, vol. 9, no. 2, June 1899. Bibliography: p. 107-109.

Thesis (Ph. D.)--University of Chicago. / Cover title. Reprinted from the Journal of comparative neurology, vol. 9, no. 2, June 1899. Bibliography: p. 107-109.

Tübingen, Univ., Diplomarb., 2000.

Thesis (Ph. D.)--University of Oregon, 2005. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 76 - 80). Also available for download via the World Wide Web; free to University of Oregon users.

The northern leopard frog (Rana pipiens) is a species that depends on landscape connectivity to complete its lifecycle. However, due to historic and present anthropogenic landscape changes, this species encounters a variety of agriculture fields during migratory and dispersal movements. These landscape changes have potential to affect habitat connectivity for these frogs and may interfere with the species? life-cycle needs. Differing land-cover types have varying effects on movement, desiccation and predation of the northern leopard frog, which in turn affect the frog?s ability to survive. Through creation and use of an agent-based model that can simulate individual frog movement on a modeled landscape, I explored habitat connectivity in the prairie-pothole region. I used northern leopard frog movement and desiccation data collected from two summers of field work to inform my modeled scenarios. The model I developed allows for the exploration of habitat connectivity under various patterns of land-cover change. / U.S. Geological Survey Climate Research and Development Program / North Dakota State University (NDSU)

M.Sc. (Zoology) / The reproductive biology of the South African leopard, Panthera pardus has not been studied in detail. In South Africa little is known about the population numbers of leopards due to their solitary and nocturnal nature and currently the conservation and management of leopard populations relies mainly on the contributions of non-governmental organisations, academic institutions and private individuals. The aim of this study was to provide baseline information for the development of in-situ and ex-situ reproductive conservation methods for the leopard. In order to meet this aim, the following objectives were established: 1) determine the degree of relatedness of the leopards sampled, 2) establish baseline parameter values of a whole blood count and describe the ultrastructure of the blood cells, 3) obtain semen by means of electroejaculation and determine the efficiency of a previously described cryopreservation protocol for leopard spermatozoa, 4) describe the morphology and ultrastructure of the leopard spermatozoa using florescence and electron microscopy, 5) describe the histology and ultrastructure of the leopard testes and the events of spermatogenesis using light and electron microscopy. Between January 2011 and February 2013, blood and semen samples were obtained from eleven leopards after being sedated with a combination of Medetomidine and Ketamine. The DNA was extracted from the blood (ARC Genetics Department) and analysed (Onderstepoort Veterinary Genetics Laboratory). The blood was also used for the analysis of the baseline blood parameter values (Lancet Laboratories). Whole blood was fixed in 2.5% phosphate buffered gluteraldehyde and prepared for transmission and scanning electron microscopy to describe the ultrastructure of the cells. Techniques to examine sperm morphology included florescence and electron xviii microscopy. The semen was fixed in 2.5% gluteraldehyde and phosphate buffer for the ultrastructural assessment. Testes samples obtained from a leopard that died during transportation were fixed in Bouin’s fixative and a phosphate buffered 2.5% gluteraldehyde solution for light and electron microscopy respectively. The testes samples were prepared using standard techniques and stained with Hemotoxylin and Eosin for light microscopy and uranyl acetate and lead citrate for electron microscopy. The DNA analysis revealed that two pairs of leopards were related on a half-sibling level. The mean parameter values of the whole blood count of P. pardus were similar to the values recorded for Asian leopards, P. pardus African lions, Panthera leo and bobcats, Lynx rufus and fell within the normal ranges for the domestic cat, Felis catus. The ultrastructural assessment of the blood cells was comparable with those that have been described for the Asian leopard as well as most other mammalian species. A small volume of semen (≤0.5 ml) could be obtained from five out of nine male leopards that were sampled. The morphology and ultrastructure of the leopard spermatozoa conforms to the generalised structure of spermatozoa of most mammalian species. A large number of morphologically abnormal spermatozoa were noted. This has also been reported for many feline species, including the Indian leopards. Spermatozoa abnormalities identified included coiled tails, cytoplasmic droplets and knobbed acrosomes. The cryopreservation of the spermatozoa yielded a maximum post-thaw progressive motility of 24.4%. The histology and ultrastructural events of spermatogenesis in the leopard testes were compared to that of the domestic cat and some differences were observed between the domestic cat testes and leopard testes. The results of this study provide baseline information on the genetic diversity and reproductive biology of the leopards in South Africa. This can be used in the development of assisted reproductive techniques that may one day aid in conservation strategies for the leopards.

Thermal ecology and movement of the Leopard Lizard, G. wistizeniwere studied at Frog Spring, adjacent to the Alvord Desert, and at various locations throughout the Alvord Basin. Seasonal activity is known to occur from early May to mid-October, but abundance. gradually decreases after late July. During favorable late spring, and summer weather lizards exhibit a bimodal pattern of diel activity with some activity occurring at all hours of the day between 0600 and 1800 H. At other times activity was unimodal. Emergence was apparently largely temperature dependent and did not occur until sand temperature approximated 21°C. Retreat appeared to be temperature independent, and was initiated by exogenous or endogenous stimuli at sand temperatures often above body temperatures acceptable for normal activity. For the period of study, juveniles exhibited diel activity patterns similar to adults, and were found during all hours in which adults were encountered. Body temperatures of field active lizards, largely affected by the immediate weather conditions, , ranged from 18.6° to 43.4°C. Because of a variety of thermoregulatory response (changes in location, posture, and orientation, color change, burrowing, shade-seeking, and panting), even during unfavorable weather conditions, most body temperatures fell within a narrower range. Nonetheless, the ability of field active lizards to precisely thermoregulate was limited, and the levels of body temperature maintained usually encompassed a broader range than those maintained in a thermal gradient. The mean body temperature of field active lizards during favorable weather conditions, and that of active lizards in a thermal gradient, did not differ significantly, and seemed to indicate a narrow range of body temperature preference. However, prevailing weather conditions were frequently unfavorable, thus limiting the extent of time during which selection of preferred body temperature could occur. Consequently, though activity depended on the attainment of certain temperature levels, G. wislizeni was forced to adapt to a broader range of body temperatures when performing most routine tasks. The necessity of precision thermoregulation is unclear, but apparently physiological efficiency was not greatly diminished over the broad range of body temperatures fiefd active lizards were often accepting. Relatively speaking, movement in G. wislizeni was extensive. Adult males occupied an average area more than twice the size of adult females and juveniles. Plotted polygons, constructed from sighting points, tended to be elongate. The extent to which lizards occupied a definite home range was uncertain. Adult males , continuously expanding the area occupied, probably lacked a home range. Adult females, demonstrating . little area expansion, perhaps maintained a home range. Territoriality by means of intraspecific display or aggression appeared negligible in G. wislizeni.Adult males did not demonstrate such behavior toward one another . Based on a limited extent of area overlap, adult females may have exhibited territoriality toward members of their sex. Movement per hour revealed results similar to area occupied, with adult males traveling an average distance of nearly three times as great as adult females and juveniles. Greatest distances frequently coincided with peak diel activity. Individual moves were frequent in adult males and juveniles, but infrequent in ~ adult females. Adult female long moves were similar in distance to adult males, but exogenous stimuli perhaps linked with home range maintenance restricted the frequency of such jaunts. Movement in G. wislizeni appeared independent of environmental thermal conditions when body temperature was within the range acceptable for normal activity. Diel movement appeared to be random in the species. Seasonal movement in juveniles, based on dispersion data, appeared directional.

Thèse d'exercice : Médecine : Nancy 1 : 2009. / Titre provenant de l'écran-titre.